I gave up on "off the shelf" power banks a long time ago. Years ago you designed a TP4056 / FS312 LiIon charger circuit. Since then I incorporate charging circuits into most of my projects. The power banks I design and use have an ON/OFF switch. That's it! NO auto-OFF.
I already do this on my power bank like 2 years ago and still in use until now. I am inspired by using the 555 timer one. But I do something more less power consumption, because pulsing constant load at the USB output still uses a lot of current in my case, because my power bank module need like above 200mA to stay awake. So instead of pulsing constant load at the output, I use the same 555 timer circuit to drive an optocoupler, thus the pin 3 and 4 of the optocoupler will connected parallel to the power button. Since the power bank also will stay awake every time we press the power button to reset the timeout, why not use 555 timer circuit to "press" the power button every 10 second or something to reset the power bank timeout so it will stay awake forever. This method use more less power because optocoupler LED doesn't need so much current to light up. I only connect 75 ohm resistor in series with the optocoupler LED pin.
@@denzo_0298 My pb is DIY one. I only bought the module with the LCD display, and made a custom housing by myself, so I already thinking for extra space for the extra circuit. But if you used a commercial power bank that already premade, you could always reduce like 1 cell to give space for extra circuit, in return, replace all cells with higher capacity per cell. For example the amount of cell inside is 5cell with 2000mAh each, 10,000mAh in total, replace it with 3000mAh cell, so you can reduce 1 cell. Now you will need only 4 cells with 3000mAh each, 12,000mAh in total, but now you have an extra space from one reduced cell. You can put your extra circuit there.
You can add an offset to the current sense with just 2 resistors: one resistor between the 10mR and VSN, and the other from VSN to GND. The first resistor allows you to offset the voltage at VSN while only drawing a very small current to GND. Example resistor values of 2.2R for first resistor, and 18k for second resistor will only waste
Sometimes there is an Easter egg to activate low power mode. Multiple presses or long press on. Other power banks have two outputs, one high current 2.1A and the other 0.5A. Choose the lower of the two. There are also LED area lights much like the resistor and that could work too. Add a switch for when it’s not needed. Or use two jacks at the same time.
As others mentioned also: insert a resistor in series with the VSN pin, the current sensing input is probably quite sensitive so the series resistor will not have much influence on its own but it makes it much easier to inject a low voltage offset on the VSN pin.
Cutting the VSN point and adding a voltage divider might help(a series resistor from shunt VSN to IC VSN, then another resistor from IC VSN to GND). That will reduce the IC VSN point voltage slightly smaller than VSP, it will think current is above threshold.
the problem with this solution is that the powerbank will never be able to go to standby mode anymore even when no load is attached to it. From that perspective n555 solution seems more flexible and less intrusive
Eplop Electronics (UK) sell a Power Bank Keep-Alive kit based on a 555 timer. Mr Carlson's Lab also did a 555 timer circuit to keep a power bank from sleeping but he chose the RC values to connect the shunt resistor for 3s and disconnect for 25s. This worked well for all but one of my powerbanks. That one fell asleep after only 12s so I added a fast option dip switch to my version of the 555 circuit.
@@sp-vt4je When coming up with the figures i settled on a quite aggressive 50% duty cycle as some powerbanks required this and i am trying to make it work with as many power banks as possible as it's a fixed device. As bornach mentioned you can get the kit version and use whichever resistor values you wish to change the duty cycle and power drawn.
I realized something better by using SOC and shorting transistor by which I can program the on/off period freely. Because some powerbanks only need about 20s pulses to stay alive and the minimum current need may also be different. The huge problem is that every powerbank behaves slightly different. Solution with USB-C PD chip is also possible but the consumption may be quite high. I will definitely measure the still draw to the chip next time.
Not sure if you are joking, but I think he uses this technique for emphasis as he completes and explanation. He appears to have had drafting experience as well, so pretty sure he has a decent stock of engineering pens in a multiple of thicknesses. Frankly, I really like this low-tech way of identifying and emphasizing an illustration or number.
Thanks for this hacks, I struggled with this for a while, I even had to add a boost converter together with a tp4056 just to avoid the power bank modules all together.
You could just hack in a completely manual override: Make a separate 10,000:1 voltage divider between VSP and ground, and then add a switch that switches the VSN pin between its original resistor point or the fixed voltage divider. As long as the switch is flipped, it will always think the same amount of current is flowing, regardless of what actually is (this does have the drawback of losing the ability to sense overcurrent, though).
I think that using a diode would be better. Just cut the trace between VSN and the shunt pad, and add a diode between VSP and VSN. Maybe will be needed to have resistor between VSN and GND to act as a load to the diode. But, even with and 0.3V diode, the IC would think it's flowing 30A and turn off as current protections, which leads me to think about a super diode, which uses an op amp to make the voltage drop of the diode be reduce by the factor of it's open loop gain
@@greatscottlab Diode could probably work, especially with voltage divider and "adding" original shunt, so that the diode v-drop divided down would provide the minimum voltage for current measuring to keep device up, while at full load the v-drop of the diode wouldn't really change that much - so the divided V measured would like be still smaller compared to the original shunt at 1-2A so the current limit shouldn't drop much - like 2x to 3x times the minimum required current for continuing to work - Schottky would go from like
I wonder if instead of pulsing a load resistor you could supply pulses to a capacitor that then powers your project, so it would pull the same average current but in narrow spikes that ought to trigger the load detection. On the plus side it should still shut down if your circuit is properly off, but on the minus side you'll have ripple which might or might not be a problem?
With the units I have they seem to play the game of averages... which is likely why he went after 100mA pulses when the verified steady current threshold was only 50mA. It's hard to tell *exactly* what is going on inside them but it would seem that the longer a load has been near the threshold, the more readily it will trip with just a slight further decrease in current. I think the pulse approach has a benefit efficiency wise because it may take a bigger hit on the averaging cap, keeping it further away from the cutoff point. That said, this is essentially what buck and boost converters do. It's an "everything you got for a moment" followed by "let that soak in", on repeat. So you could probably half get around this simply by using another converter that follows the one in the battery. It isn't going to really "gain" you much tho, you're adding on another "base" load that doesn't actually "do" anything, putting you back in simple minimum load resistor category.
I think these approaches are still very valuable, personally I'd rather use my old power banks that have nothing else to do to power my projects rather than buying more new expensive ones and wasting the old, otherwise perfectly good ones.
This video reminded me of a car ride when I was little. It was hot and I decided to make a portable fan to cool down (car didn't have ac). Like a day prior to the trip I got an old usb cable and a 12V fan and connected them together. The fan was spinning pretty slowly but it was enough to get a cool sensation on your skin. The drive took a few hours and 3/4 of the way I was clicking the button on my power bank to wake it up like every 30seconds becouse the fan wasn't drawing enough current to keep it awake. Good times...
Great idea! It's very frustrating that with so many little gadgets getting USB-C nowadays for their tiny batteries or low power draw, your best quality power banks are the most likely to refuse to recognise them.
I really hate USB-C. It should be a standard, not a family of standards. There are already dedicated connectors for all the things it does, but there is no confusion what port and what cable support what standards, what bricks can deliver what PD mode, etc..
Literally from the datasheet for IP5328P: "If key is pressed, whether or not load is on VOUT1 port, VOUT1 port output will be force to open; but the VOUT2 and USB C port will open only when load is detected on the according port, or the output on these port will be closed. So VOUT1 must be retained if only one VOUT port is needed, if VOUT2 or VBUS is not needed, MOSFET can be eliminated, but the 10uF capacitor should be retained." And, if you need all ports to be working - thus lesser voltage on VSN pin. So then cut the trace and attach a voltage divider(100 to 1 to get 4.95v, 1000 to 1 to get 4.995v) from shunt to the VSN, simple as that.
As a regular viewer of your channel, this video is very much useful for electronics hobbyist like me , I have tested and works fine ❤❤❤ Now I can run very low current loads without "No load shutdown" problem....Once again thanks a lot 🙏
It can be insanely frustrating trying to buy a power bank when most don't publish the full specs or features they have. It can often feel like a gamble. One feature I like is pass through which allows for the battery to charge while also discharging it great to use like a sort of UPS. Also nice for connecting small solar panels too things you need to power throughout the night until the sun comes back up. Maybe this would be hard but it would be cool to be able to buy one endorsed by you
For low power projects it's easier to take 2s liio batteries with xt30 which is usually made for RC stuff and add simple usb converter and over discharge protection
IMHO just buying a cheap type C trigger board that lets me use any of my existing power banks is much easier than effectively building a custom power bank from scratch
I love the idea with the 555 circuit and if you want to make it even more efficient you can use as load a capacitor that discharges via a diode at the 5v output or feeds the 555
I use a lot of those power bank modules in my projects. I go around this limitation in my projects by using one of the MCU pins in the main project board to drive a transistor to flash an LED or just shunt current through a resistor intermittently to keep the circuit "alive".
@@fusseldieb Mine is actually part of the circuit and not an attachment to the USB port. Instead of a 555, the flashing is handled by the MCU of the main circuit
I built my own using a TP4056 and a SDB628 (MT3608) boost converter module for less than 50 cents for both!!! Added two USB connectors, power switch, terminal blocks, and enclosed in a 3D printed case. Voila. Always on @ +Whatever volts. That boost converter is magic. works down to 2V which consuming microAmps of quiescent current. Brilliant times.
Fascinating indeed! I guess the solution would be to go with USB C and embed that circuit into the project itself (so you don't need 2 USB cables). Thanks, dude! 😊 Stay safe there with your family! 🖖😊
I believe the PD protocol requires some kind of handshake between the device and the power source, and this means you actually need to integrate some suitable ic in your PCB
Could you not bypass the shunt completely - just swap it with a 0ohm, so 5V goes to both VSP and the USB port without interruption, then put a 1ohm resistor from that 5V line to VSN, so regardless of the current actually drawn, VSN sees the drop from 5V to 4.98V (assuming VSN sinks 30mA) and this is over the 18mA threshold to keep it on?
I solved this in the past by having timed pulse on one of the spare pins on Arduino controlling a fet with 150 ohm/1w resistor. To power up the power bank I wired another resistor with its power button. Works great.
The older, single cell powerbanks don't automatically shut off, no matter the load. I upgraded the cells in a bunch of them, to have more available capacity.
From the datasheet"Discharge: If key not pressed, only when sink device attached will the output port open, non-attached output port will not open. If the opened output port current is less than 180mA @ 10mOhm, it will wait for a period of time before close the port automatically. The output current is detected by the voltage drop between VSN to output, 180mA current is equivalent to 1.8mV on 10mOhm, when the resistance (including MOSFET internal resistance) between VSN and ouput is larger than 10mOhm, the current threshold will be decreased proportionally." So all you need to do is attach a 555 timer to the KEY pin and pulse it periodically. It should stay on without drawing extra current or messing with the current sense
If the powerbank comes with wakeup button (or the control IC has a pin for that), you could use a 555 timer to trigger it in certain intervals (depending on IC's sleep timer... check datasheet). Should be even more efficient, than the 555 Timer with load solution. Or, you could check the Datasheet, whether the sleep timer itself can be set/changed (e.g. via resistor). Though that is unlikely possible in most. Oh, and to save some more power, you use a CMOS variant of the 555.
Simulating dead man's button... nice... but you need to open the powerbank and solder. If you for some device use multiple powerbanks (e.g. replace with another one newly charged) you must do this modification for each of them.
Simulating dead man's button... nice... but you need to open the powerbank and solder. If you for some device use multiple powerbanks (e.g. replace with another one newly charged) you must do this modification for each of them.
@@vencdee I mean, there are powerbanks, that can be easily opened. I personally prefer powerbanks that are filled with 18650 cells, that you can easily replace. On those you have easy access to the PCB. And if you do many projects, you might want to add one additional to the top of the list, a custom powerbank. There are plenty of good pre-built powerbank circuits available, along with 18650 cells. But of course, there are different solutions for different kinds of people with different skillsets and levels.
Hi, as many projects require 3.3V and not 5V, you can use a 3.3 LDO regulator with overdischarge protection directly on the li-ion or li-po battery inside the powerbank. 3V is enough for low power projects (SMt32 + data acquisition + oled for exemple) , a low cost LDO is sufficient in this case
If you're going to that much trouble, just get the lithium battery and the battery bank circuit and use it for charging only, then wire the lithium battery to a voltage circuit or just use as it for your project.
If your project contains microcontroller and you have spare output pin and some space on board you can program pulse draw, or use second small dedicated microcontroller like Attiny5 and some transistor with load resistor to do it.
Many power banks do come with a low power draw mode. What I would like to see is to **how to use them as UPSes** since most of them turn off for a second when AC power turns off or on.
I think rather the cheap ones turn off when AC-power changes to have a cheap but still safe renegotiation of protocols and capabilities. But you can probably be super cheap and simply add a large enough capacitor to survive the downtime. While they do work greatfor UPS applications, such on-line UPS systems wear out the battery quickly. better would be to use it as standby once power drops (like most USPs do)
Modifying a power bank to act as a UPS would be much more complex than these mods, so it probably makes more sense to just buy a power bank with passthrough charging/UPS mode to begin with (fairly common these days).
I've built such a circuit on a breadboard a while back. I chose the 555 timer route because it's simple and dosen't draw much power. My powerbank (20000mAh) turns off after 30 seconds with no or too little load. That current threshold is around 70mA with my powerbank. So my circuit draws around 150mA for around a second every 20 seconds. My (USB operated) NiMh battery charger can sometimes draw too little current for the powerbank to stay on.
The datasheet lists a parameter about light load detection which uses the voltage between the positive USB voltage rail (connected to pin VOUT1/2, VBUS) and VSN. Seems like they use the output FET as a shunt. If less than 1.8mV is measured, light load is detected. Maybe a low forward voltage diode (e.g. Schottky diode) between the positive USB rail and VOUT could do the trick without affecting charge/discharge current protection. Although, the datasheet is a bit conflicting at that point 🤔
Instead of trying to increase voltage of the IC VSP pin , it might be better choice to cut the VSN pin of the ic and put a resistor between shunt VSN TO IC VSN and a another resistor between IC VSN TO GROUND so that the ic vsn pin voltage get reduced than IC VSP voltage, may be it will think output current is above the threshold value
Another annoying problem is that most powerbanks turn off the output when you connect a charger. Otherwise you could use them as a small UPS. For a raspberry pi for Example...
I've figure out that this also depends on the voltage of the charger. If charger has a good cable and the voltage on the input port stays close to 5V my power bank doesn't turn of the load and indeed works like a small UPS. But if you plug it in a weak charger and the voltage on the input drops to say 4.5 it disconnects the load until fully charge itself.
Some powerbanks have what's called a "Trickle charge" mode.. This mode forces the powerbanks output to always stay on. I've seen it being a thing on some of Anker's powerbanks, where you longpress the powerbutton and the indicator LED turns from blue to green...
You can just use an usb-c powerbank with a type-c breakoiut board, set both CC 5.1K to GND with a resistor to get 500mAh output on that port and keep all other ports awake with higher output.
What size are those shunt resistors (1206)?, you should be able to find or stack resistors rather than just unsoldering it, however the testing to figure out how to fix the shutdown problem is pretty awesome! Keep em coming!!!!
Those are great! I love the pulse circuit! Ingenious! had that shutdown problem once, and since then, I have bought power banks that support low current devices. With the Anker 737 I have right now you can hold the button down for a few seconds to lock on. And draw as little as you want.
Although he wasn't the first to make use of a 555 for this purpose. I recall Mr Carlson's Lab made a version in a video titled "Power Bank Stay Awake!" over 3 years ago.
I just replaced the momentary button with a self locking one it kept the power bank on forever the bonus here that stand by mode could be switched on or off 😁😁
It's nice to see Scott using Everyone's Favorite Timer Chip in a project again. Coulda done it with a cheap, ubiquitous microcontroller, but where's the sport in that? (Seriously, as much as I love the 555, there's something to be said for a chip that only requires a bypass capacitor and a load resistor to perform the same function, and the micro could easily be heat-shrinked into a tiny USB pass-through dongle.) By the way, Paul Carlson built a similar 555 timer "stay awake" circuit a few years ago. It still bugs me that power bank enginerds don't realize that many consumers need this functionality.
It feels wrong using an entire microcontroller to just pulse a circuit though :/ As for power bank engineers, they do realise, it didn't actually take very long after low power type C devices like true wireless headphones came on the market for power banks to start including low power modes. The problem is that the cheap power banks just recycle the old designs so you usually only get these modes on mid to higher end ones.
@@bosstowndynamics5488 I meant the ubiquitous $0.03 one-time programmable 6- or 8-pin chips. Just a few lines of code to grab a brief pulse of current every few seconds, 100 nanofart bypass capacitor, appropriately sized load resistor, USB connector traces directly on the PCB...Bob's your auntie.
Funny, because i recently made exactly the opposite experience. 😄 I bought absolutely cheap beard trimmer for traveling. But this one had a) old NiMh batteries and b) an extra adapter. So i used a step down converter to the used 3V and an old USB cable to use it with a standard USB adapter. But than the charging always stopped after less than a Minute! I thought a made a mistake but than i realized that this only happens when the battery is full and the flow is dropping. Which is perfect because the original Adapter dopes not stop charging, so you never knew when the battery was already full. But because of the auto-stop of the converter now it does. So now i have a USB cable to charge and additional an auto-stop. Win-win. 😄
for these earlier power banks, you can put a switch on that resistor circuit, so you can get what most commenters are saying: a "trickle charge" or "low power" mode where you basically switch between the ultra-low power mode and normal operation, depending on your needs
I use the pulse method in a small circuit mounted on top of the 555 itself that I put inside the power banks and it pulses the output every 30 seconds for 1 second, and it works fine...!!! Great video.
A better option is another lower power piggybacked power bank of your own design. Just need to isolate and regulate output from charging input so as no over voltage or spike on the low power device at the very end of the chain! Just need to turn on the first in the chain occasionally to charge the second. Easy and less work. Simplest option of all: plug into a mains usb charger which won't cut out for low power devices! :-)
Also a problem with some small synthesizers. I found that some old small cheap powerbanks don't have a switch-off (ir it is very low). One soultion: using a USB hub and plugging in a USB lamp additionally. Then it stays on.
Great designs! I think the 555 circuit is plenty good enough for people that need the convenience of a powerbank. The "pre-made" power banks are meant for expedient use anyway so as long as it's not discharging the battery for nothing it's fine. People that actually care about doing a "most efficient battery powered IoT whatever" will just embed the battery and add a basic BMC in their device (ie the little boards that just protect the li-ion cells from over/under voltage and overcurrent). Nobody should be getting a power bank and then try to hack it, just get a BMC board and cells and make a "dumb" battery
Great video! I like the pulse circuit. Could dial it in to trigger right before the shut down of the power bank to minimize how much power is drawn instead of the 8 second interval used for demonstration. Maybe as a subsystem added to the small projects themselves to allow function with any power bank without external modules. I know the current draw is quite small, but were there any voltage dips presented on the output side from the pulse?
Im sure I’m not the first one to mention this but most usb powerbank have two outputs, so you could put the timer in one and your application in another. It would probably be fairly easy to miniaturize into a tiny dongle.
IP5328 have I2C communication, u can easily configure this behavior throuhg it. First power on by button , to power the mcu, mcu sending "always on" to IP5328. This shunt 10mOhm it's for charging/boost current sense. I bet the whole IC get crazy after you changed it :)
If your just powering an ESP32 with the power bank then just use a bare 1s 18650 battery pack. The boost converter that steps the 4.2v to 5v does draw some power as in those aliexpress 3 for something .99 diy power banks.
If you cut the trace to the LOWER of the two current sense inputs and add a 1:10000 voltage divider, the measured current will be about .5mV higher than what it really is. No opamp required. The only drawback is that the "amplification circuit" inside the chip may expect an about 10mOhm output resistance of the current sense resistor so it might be designed to draw a significant current. But I'd start out with a pretty high-impedance voltage divider. At such a ratio the big resistor actually becomes "almost a current source" So you almost get an actual .5mV offset as you wanted. Try 1M/100 Ohm, if that doesn't work, try 100k/10 and 10k/1 ohm respectively.
My powerbank can actually be set to a "disable auto shutdown"-mode which also switches off any fast charging. It just provides stable 5V. It's a ROMOSS Sense 8P+. The mode can be activated by a double tap on the on/off button while it's on.
You could also add a switch to bridge your higher value sense resistor with the smaller resistor for the times when you need to supply higher currents.
I've worked on a similar probkem, but my circuit can also be powered by standard 3.3V. My sokution was to buy a DYI powerbank, female USB-C which i drilked a hole for, and a 1S BMS. Connecting the 1S BMS in parallel to the battery connections on the powerbank cirxuit, and then to the female USB-C. Now im able to pull directly from the batteries, without step-up loss, have some protection, and can be charged like a regular powerbank (using the existing connections).
I bought a power bank that has 4x 18650 protected button top cells wired in parallel and they are user replaceable with a slide off battery cover. I slide the battery cover off and insert the jumper leads to + and - bypassing the the electronic circuit board if I want to use with low power devices like micro controllers. It provides plenty of runtime for small loads, and if I want to be more exact with voltage or use maximum amount of power from the 18650, then I can plug a small DC-DC boost converter.
10:30 Couldn't you just use a higher value resistor, like say 20mOhm or 100mOhm? Correct me if there is a flaw in my thought, but it would just lead to a bigger voltage drop, over the resistor, thus the IC thinking it is a bigger current flowing. (Yes you would lose some Amperage potential in higher current application, say the circuit shuts off at 500mA instead of 1A due to our falsely increased overcurrent reading)
A couple years ago I made a 3S pack using a cheap BMS board and a buck converter, put a toggle switch on it and wrapped it in fish paper (after I had an oops and had to replace the BMS board). Crude but effective. I did have to dedicate a power supply to it for charging with a current limiting circuit hacked onto it to prevent the supply from shutting down on overcurrent when charging.
This is a great succinct example of why everyone hates software and technology: A designer or company makes one assumption, and there will always be a huge number of people that don't want that as a feature. And thus nothing ever does exactly what people want
Did you consider making an additional port for your “ultra low power” projects, and using the normal ports for projects that you do want the shutoff protection?
The engineer who thought that shutting off the power bank if it does not detect 500ma is a id10t. Its in the same field as a cloud service for appliances.
Well these things were mostly designed for phone charging, and even old phones usually drew at least 500ma. Newer banks take into account that you might be using them for other things.
I experienced it alot, An led can also be used as a load for output spikes preferably an SMD one. Or just force button press of the power bank to keep it turned on all the time using of course a signal instead of manually physically doing it.
Someone mentioned that some power banks such as those from Xiaomi can go to "Low Current Discharge Mode" by double pressing the battery check button (and exit by simply pressing the battery check button). This however, still has a potential problem that this mode will end in 2 hours. This may be good if you use it to charge your wireless earphones but in my case, I want to use the power bank to drive a water fountain for my cat (which draws about 40mA current, and don't have a near by mains socket) so I want it to be able to run as long as possible. Another question on Scott's hacks is, will the power bank still be protected from over-discharging, especially when the pulse circuit is added?
Yes the cells are protected against over discharge regardless, no matter that you apply constant load or wake-up circuit with intermittent load. Except on the very cheapest of power banks, not reputable ones, which can only turn off boost but then the battery voltage is still on the output terminals, so instead of 5V something in 3V-4.2V range is present when it's sleeping. But you could say those don't have a functioning over discharge protection to begin with, sure a phone would stop charging, but LEDs, heating gadgets and other simple devices could overdrain such a power bank. You better check if you have those around.
I highly recommend big powerbank empty cases for 18650. It's the best case for DIY electronics. - no need for hack like in video, just connect pin as input and u can read button pushes for custom special actions and every 10-30s set the same pin as output high for few ms to mimic single button push and that will prevent powerbank from turning off. - dont use all 18650, take one of two less and put mcu there.. - cut plus or minus line from usb port and put mosfet in the middle and u have 5v line that is being controlled by PWM - if u need more control then single button can provide u can remove LED and put pushbutton there (no need to drilling that is never perfectly centered so if have OCD u still be happy how project looks in the end) - case for 8 cells (and u can put up to 7) costs only 5$ (cheaper then plastic case, usb ports and li-on charger separately)
The controller wants to see a small voltage drop. Too small and it thinks there is no load (must shut down after a while to save power). Too high and it thinks the load is too large (must shut down immediately).
5:11 As a newbie to electronics can someone in layman’s term explain why on the output Vcc is connected to GND 🤔. Listened through a couple of times and seemed to have missed something. TIA
The shunt resistor mod gives me an idea... what about a voltage divider on the 555's reset pin, carrying (or transistor buffering) current? Pull RESET low when current exceeds a certain threshold, so we're not unnecessarily pulsing the load when the attached device exceeds the minimum draw. Might be useful for something like a remotely deployed ESP32, where it''s mostly idle, but occasionally has a bunch of Wi-Fi connected work to do, for example.
I work mainly with phones. For example, just by the current that the iPhone draws, you can tell what is damaged in it. I have a 20,000mAh and 20W Powerbank from BaseUS and it drives me nuts when it turns off after 15 seconds of no or low power consumption (around 0.05A). I was thinking about making a PCB for it to artificially consume power, but I put it off until later. Btw my old Xiaomi 10 000mAh Powerbank with 5V2A output supports low power mode by simply clicking power button 2-3 times. Then it will never turn off, but I can't always use it, especially when I need Fast Charging. Thanks GreatScott!
The IP 5328 chip is programmable, granted it only mentions charge curves, but probably also has provisions for setting the auto shut off value. Using TP4056 and a 18650 cell we bypass the cut-off problem altogether. And while the TP4056 draws 20µA that will take awhile to discharge with no load attached.
Cool video. Could you do a video like this for battery powered bluetooth speakers? I have a similar problem, it seems. I have scoured the market for a decent portable battery powered speaker that I can use as a speaker for portable keyboards/groove boxes. I don't even care about the BT functionality, I just want the ability to plug a headphone cable out of my music device and into the aux in of the speaker. The problem with this is that every speaker I have tried seems to have a similar auto-shutoff so if I stop playing even for just a few moments, then the speaker goes to sleep and it takes a few strikes of the keyboard to wake it up again. I wonder if if this has a similar solution, where we can remove the autosleep altogether, or perhaps send it a subsonic or supersonic audio pulse at regular intervals to keep it awake. Of course if it is an outside of case solution, I don't know how I would power the thing that creates the pulse.
i faced similar issue to power up my lcd clock from a power bank which would turn off in a minute due load current of less than 1mA, so i made a bms with a boost circuit to 5V which never turns off still working great.
My power bank (A+) stays on if I periodically press the button. Maybe a 555 timer that periodically mimics a button press would work and would be very efficient. I don't know if it work on all power bank tho.
One thing I would like to see is a low voltage input cutoff on powerbanks. I have several that will draw all the way down and not shut off when they get low. I don't like the batteries going that low. Luckily I'm using recycled laptop batteries that were free. They would last longer if they didn't draw down so low.
low power mode can be activated on majority of branded powerbanks. the real problem is that some powerbanks may turn off after charging your device instead of acting like a wall charger (until power bank drains).
Yay for the 555. Useful in 1978* Still useful in 2024! * Marketed in 1972. But I was using it as a kid a tad later 😅 Think the cmos version came out in my youth too...
Hi love all your videos. Anyway you could hack a power bank to become passthrue power bank (like having usb camera that can stay on after powr failure or evan Rasberry PI) without the need to buy ups?
I gave up on "off the shelf" power banks a long time ago. Years ago you designed a TP4056 / FS312 LiIon charger circuit. Since then I incorporate charging circuits into most of my projects.
The power banks I design and use have an ON/OFF switch. That's it! NO auto-OFF.
I already do this on my power bank like 2 years ago and still in use until now. I am inspired by using the 555 timer one. But I do something more less power consumption, because pulsing constant load at the USB output still uses a lot of current in my case, because my power bank module need like above 200mA to stay awake. So instead of pulsing constant load at the output, I use the same 555 timer circuit to drive an optocoupler, thus the pin 3 and 4 of the optocoupler will connected parallel to the power button. Since the power bank also will stay awake every time we press the power button to reset the timeout, why not use 555 timer circuit to "press" the power button every 10 second or something to reset the power bank timeout so it will stay awake forever. This method use more less power because optocoupler LED doesn't need so much current to light up. I only connect 75 ohm resistor in series with the optocoupler LED pin.
How do you fit an extra circuit in your power bank??
@@denzo_0298 My pb is DIY one. I only bought the module with the LCD display, and made a custom housing by myself, so I already thinking for extra space for the extra circuit.
But if you used a commercial power bank that already premade, you could always reduce like 1 cell to give space for extra circuit, in return, replace all cells with higher capacity per cell. For example the amount of cell inside is 5cell with 2000mAh each, 10,000mAh in total, replace it with 3000mAh cell, so you can reduce 1 cell. Now you will need only 4 cells with 3000mAh each, 12,000mAh in total, but now you have an extra space from one reduced cell. You can put your extra circuit there.
Pure genius... dead man's button for powerbank... excellent idea!
You can add an offset to the current sense with just 2 resistors: one resistor between the 10mR and VSN, and the other from VSN to GND. The first resistor allows you to offset the voltage at VSN while only drawing a very small current to GND. Example resistor values of 2.2R for first resistor, and 18k for second resistor will only waste
Sometimes there is an Easter egg to activate low power mode. Multiple presses or long press on. Other power banks have two outputs, one high current 2.1A and the other 0.5A. Choose the lower of the two. There are also LED area lights much like the resistor and that could work too. Add a switch for when it’s not needed. Or use two jacks at the same time.
As others mentioned also: insert a resistor in series with the VSN pin, the current sensing input is probably quite sensitive so the series resistor will not have much influence on its own but it makes it much easier to inject a low voltage offset on the VSN pin.
Cutting the VSN point and adding a voltage divider might help(a series resistor from shunt VSN to IC VSN, then another resistor from IC VSN to GND). That will reduce the IC VSN point voltage slightly smaller than VSP, it will think current is above threshold.
Yup, was about to suggest that
the problem with this solution is that the powerbank will never be able to go to standby mode anymore even when no load is attached to it. From that perspective n555 solution seems more flexible and less intrusive
@@borincod yes you’re right it would probably drain batteries much faster when the Power bank is stored with no load.
Eplop Electronics (UK) sell a Power Bank Keep-Alive kit based on a 555 timer. Mr Carlson's Lab also did a 555 timer circuit to keep a power bank from sleeping but he chose the RC values to connect the shunt resistor for 3s and disconnect for 25s. This worked well for all but one of my powerbanks. That one fell asleep after only 12s so I added a fast option dip switch to my version of the 555 circuit.
Many thanks for the mention.
It has a 50% duty cycle tho, which is too much
@@sp-vt4je When coming up with the figures i settled on a quite aggressive 50% duty cycle as some powerbanks required this and i am trying to make it work with as many power banks as possible as it's a fixed device. As bornach mentioned you can get the kit version and use whichever resistor values you wish to change the duty cycle and power drawn.
I realized something better by using SOC and shorting transistor by which I can program the on/off period freely. Because some powerbanks only need about 20s pulses to stay alive and the minimum current need may also be different. The huge problem is that every powerbank behaves slightly different.
Solution with USB-C PD chip is also possible but the consumption may be quite high. I will definitely measure the still draw to the chip next time.
Someone needs to get this man a bolder marker so that he doesn't have to go over everything he writes multiple times.
I like it that way though ;-)
😂😂😂 rightly said
Leave his OCD alone. 🤣
Not sure if you are joking, but I think he uses this technique for emphasis as he completes and explanation. He appears to have had drafting experience as well, so pretty sure he has a decent stock of engineering pens in a multiple of thicknesses.
Frankly, I really like this low-tech way of identifying and emphasizing an illustration or number.
@@allthings3d I was joking, yes. I appreciate the drafting information though. I was not aware of that. Thanks!
Thanks for this hacks, I struggled with this for a while, I even had to add a boost converter together with a tp4056 just to avoid the power bank modules all together.
Glad I could help :-)
You could just hack in a completely manual override: Make a separate 10,000:1 voltage divider between VSP and ground, and then add a switch that switches the VSN pin between its original resistor point or the fixed voltage divider. As long as the switch is flipped, it will always think the same amount of current is flowing, regardless of what actually is (this does have the drawback of losing the ability to sense overcurrent, though).
I think that using a diode would be better. Just cut the trace between VSN and the shunt pad, and add a diode between VSP and VSN. Maybe will be needed to have resistor between VSN and GND to act as a load to the diode.
But, even with and 0.3V diode, the IC would think it's flowing 30A and turn off as current protections, which leads me to think about a super diode, which uses an op amp to make the voltage drop of the diode be reduce by the factor of it's open loop gain
Hmmmm also sounds interesting.
@@greatscottlab Diode could probably work, especially with voltage divider and "adding" original shunt, so that the diode v-drop divided down would provide the minimum voltage for current measuring to keep device up, while at full load the v-drop of the diode wouldn't really change that much - so the divided V measured would like be still smaller compared to the original shunt at 1-2A so the current limit shouldn't drop much - like 2x to 3x times the minimum required current for continuing to work - Schottky would go from like
Not that long ago I had to browse the internet in the search of something like this for a project. Really nice to see it well documented in a video.
I wonder if instead of pulsing a load resistor you could supply pulses to a capacitor that then powers your project, so it would pull the same average current but in narrow spikes that ought to trigger the load detection. On the plus side it should still shut down if your circuit is properly off, but on the minus side you'll have ripple which might or might not be a problem?
With the units I have they seem to play the game of averages... which is likely why he went after 100mA pulses when the verified steady current threshold was only 50mA.
It's hard to tell *exactly* what is going on inside them but it would seem that the longer a load has been near the threshold, the more readily it will trip with just a slight further decrease in current.
I think the pulse approach has a benefit efficiency wise because it may take a bigger hit on the averaging cap, keeping it further away from the cutoff point.
That said, this is essentially what buck and boost converters do. It's an "everything you got for a moment" followed by "let that soak in", on repeat.
So you could probably half get around this simply by using another converter that follows the one in the battery. It isn't going to really "gain" you much tho, you're adding on another "base" load that doesn't actually "do" anything, putting you back in simple minimum load resistor category.
You just need to spend more on your powerbanks. The ones I have can be put in a trickle mode which disables the low current shutoff.
Yeah I have an Anker one. I just double click the button on it, and it goes into trickle mode. Works great
@@mattanderson111 Mine are Ankers too, l wouldn't buy one without the trickle feature, it's very useful.
Honestly never heard of this feature. But awesome that something like this is out there.
I think these approaches are still very valuable, personally I'd rather use my old power banks that have nothing else to do to power my projects rather than buying more new expensive ones and wasting the old, otherwise perfectly good ones.
This video reminded me of a car ride when I was little. It was hot and I decided to make a portable fan to cool down (car didn't have ac). Like a day prior to the trip I got an old usb cable and a 12V fan and connected them together. The fan was spinning pretty slowly but it was enough to get a cool sensation on your skin. The drive took a few hours and 3/4 of the way I was clicking the button on my power bank to wake it up like every 30seconds becouse the fan wasn't drawing enough current to keep it awake. Good times...
Haha thanks for the story :-)
@@greatscottlab Thanks!
You had USB when you were little!? Now I feel old
@@stefflus08 Yes, in a while I will start to feel old.
@@stefflus08 and powerbanks too... yupp, feeling old over here too...
Great idea! It's very frustrating that with so many little gadgets getting USB-C nowadays for their tiny batteries or low power draw, your best quality power banks are the most likely to refuse to recognise them.
@LewisOSLife2984Patreon.
@LewisOSLife2984the video is released earlier for people who pay
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I really hate USB-C. It should be a standard, not a family of standards. There are already dedicated connectors for all the things it does, but there is no confusion what port and what cable support what standards, what bricks can deliver what PD mode, etc..
Literally from the datasheet for IP5328P:
"If key is pressed, whether or not load is on VOUT1 port, VOUT1 port output will be force to open; but the
VOUT2 and USB C port will open only when load is detected on the according port, or the output on these port
will be closed. So VOUT1 must be retained if only one VOUT port is needed, if VOUT2 or VBUS is not needed,
MOSFET can be eliminated, but the 10uF capacitor should be retained."
And, if you need all ports to be working - thus lesser voltage on VSN pin. So then cut the trace and attach a voltage divider(100 to 1 to get 4.95v, 1000 to 1 to get 4.995v) from shunt to the VSN, simple as that.
but that ruins his example... lol
As a regular viewer of your channel, this video is very much useful for electronics hobbyist like me , I have tested and works fine ❤❤❤ Now I can run very low current loads without "No load shutdown" problem....Once again thanks a lot 🙏
I did a pulse circuit with a Attiny13, it had far less components, and cost around the same if you are not mass-producing it.
It can be insanely frustrating trying to buy a power bank when most don't publish the full specs or features they have. It can often feel like a gamble. One feature I like is pass through which allows for the battery to charge while also discharging it great to use like a sort of UPS. Also nice for connecting small solar panels too things you need to power throughout the night until the sun comes back up. Maybe this would be hard but it would be cool to be able to buy one endorsed by you
For low power projects it's easier to take 2s liio batteries with xt30 which is usually made for RC stuff and add simple usb converter and over discharge protection
IMHO just buying a cheap type C trigger board that lets me use any of my existing power banks is much easier than effectively building a custom power bank from scratch
“Micro watt hour per minute” is my new favourite unit
I love the idea with the 555 circuit and if you want to make it even more efficient you can use as load a capacitor that discharges via a diode at the 5v output or feeds the 555
I use a lot of those power bank modules in my projects. I go around this limitation in my projects by using one of the MCU pins in the main project board to drive a transistor to flash an LED or just shunt current through a resistor intermittently to keep the circuit "alive".
Basically what he showed in the video lol
@@fusseldieb Mine is actually part of the circuit and not an attachment to the USB port. Instead of a 555, the flashing is handled by the MCU of the main circuit
I built my own using a TP4056 and a SDB628 (MT3608) boost converter module for less than 50 cents for both!!!
Added two USB connectors, power switch, terminal blocks, and enclosed in a 3D printed case. Voila. Always on @ +Whatever volts.
That boost converter is magic. works down to 2V which consuming microAmps of quiescent current. Brilliant times.
Fascinating indeed! I guess the solution would be to go with USB C and embed that circuit into the project itself (so you don't need 2 USB cables).
Thanks, dude! 😊
Stay safe there with your family! 🖖😊
Good point!
Does USB C even need anything more complicated than a couple of resistors on the CC pins?
@@Vaionko That's a good question, I don't really know.
I believe the PD protocol requires some kind of handshake between the device and the power source, and this means you actually need to integrate some suitable ic in your PCB
@@giovannigrosso6920You can buy little PD boards for around $2. Very useful
Could you not bypass the shunt completely - just swap it with a 0ohm, so 5V goes to both VSP and the USB port without interruption, then put a 1ohm resistor from that 5V line to VSN, so regardless of the current actually drawn, VSN sees the drop from 5V to 4.98V (assuming VSN sinks 30mA) and this is over the 18mA threshold to keep it on?
Yeah what other me said... I feel like I'm missing something obvious though!
I solved this in the past by having timed pulse on one of the spare pins on Arduino controlling a fet with 150 ohm/1w resistor. To power up the power bank I wired another resistor with its power button. Works great.
I was looking for this topic previously, now I know how to keep them alive
Glad I could help :-)
The older, single cell powerbanks don't automatically shut off, no matter the load. I upgraded the cells in a bunch of them, to have more available capacity.
From the datasheet"Discharge:
If key not pressed, only when sink device attached will the output port open, non-attached output port will
not open. If the opened output port current is less than 180mA @ 10mOhm, it will wait for a period of time before
close the port automatically. The output current is detected by the voltage drop between VSN to output, 180mA
current is equivalent to 1.8mV on 10mOhm, when the resistance (including MOSFET internal resistance) between
VSN and ouput is larger than 10mOhm, the current threshold will be decreased proportionally."
So all you need to do is attach a 555 timer to the KEY pin and pulse it periodically. It should stay on without drawing extra current or messing with the current sense
If the powerbank comes with wakeup button (or the control IC has a pin for that), you could use a 555 timer to trigger it in certain intervals (depending on IC's sleep timer... check datasheet). Should be even more efficient, than the 555 Timer with load solution.
Or, you could check the Datasheet, whether the sleep timer itself can be set/changed (e.g. via resistor). Though that is unlikely possible in most.
Oh, and to save some more power, you use a CMOS variant of the 555.
Simulating dead man's button... nice... but you need to open the powerbank and solder. If you for some device use multiple powerbanks (e.g. replace with another one newly charged) you must do this modification for each of them.
Simulating dead man's button... nice... but you need to open the powerbank and solder. If you for some device use multiple powerbanks (e.g. replace with another one newly charged) you must do this modification for each of them.
@@vencdee I mean, there are powerbanks, that can be easily opened. I personally prefer powerbanks that are filled with 18650 cells, that you can easily replace. On those you have easy access to the PCB.
And if you do many projects, you might want to add one additional to the top of the list, a custom powerbank. There are plenty of good pre-built powerbank circuits available, along with 18650 cells.
But of course, there are different solutions for different kinds of people with different skillsets and levels.
Hi,
as many projects require 3.3V and not 5V, you can use a 3.3 LDO regulator with overdischarge protection directly on the li-ion or li-po battery inside the powerbank. 3V is enough for low power projects (SMt32 + data acquisition + oled for exemple) , a low cost LDO is sufficient in this case
If you're going to that much trouble, just get the lithium battery and the battery bank circuit and use it for charging only, then wire the lithium battery to a voltage circuit or just use as it for your project.
If your project contains microcontroller and you have spare output pin and some space on board you can program pulse draw, or use second small dedicated microcontroller like Attiny5 and some transistor with load resistor to do it.
Yup, I've done this. Spare PWM pulsing the power with a MOSFET.
Many power banks do come with a low power draw mode. What I would like to see is to **how to use them as UPSes** since most of them turn off for a second when AC power turns off or on.
I think rather the cheap ones turn off when AC-power changes to have a cheap but still safe renegotiation of protocols and capabilities.
But you can probably be super cheap and simply add a large enough capacitor to survive the downtime.
While they do work greatfor UPS applications, such on-line UPS systems wear out the battery quickly. better would be to use it as standby once power drops (like most USPs do)
@@tarakivu8861 Would it be safe to add a 1.5F 5.5V Super Capacitor across the power bank's output? I would like to use it as a UPS for raspberry pi 4.
Modifying a power bank to act as a UPS would be much more complex than these mods, so it probably makes more sense to just buy a power bank with passthrough charging/UPS mode to begin with (fairly common these days).
I've built such a circuit on a breadboard a while back. I chose the 555 timer route because it's simple and dosen't draw much power. My powerbank (20000mAh) turns off after 30 seconds with no or too little load. That current threshold is around 70mA with my powerbank. So my circuit draws around 150mA for around a second every 20 seconds. My (USB operated) NiMh battery charger can sometimes draw too little current for the powerbank to stay on.
Nice Video. But a few warnings are missing for unexpierenced people. Especially for soldering Lithium Batteries
The datasheet lists a parameter about light load detection which uses the voltage between the positive USB voltage rail (connected to pin VOUT1/2, VBUS) and VSN. Seems like they use the output FET as a shunt. If less than 1.8mV is measured, light load is detected. Maybe a low forward voltage diode (e.g. Schottky diode) between the positive USB rail and VOUT could do the trick without affecting charge/discharge current protection. Although, the datasheet is a bit conflicting at that point 🤔
Instead of trying to increase voltage of the IC VSP pin , it might be better choice to cut the VSN pin of the ic and put a resistor between shunt VSN TO IC VSN and a another resistor between IC VSN TO GROUND so that the ic vsn pin voltage get reduced than IC VSP voltage, may be it will think output current is above the threshold value
Another annoying problem is that most powerbanks turn off the output when you connect a charger. Otherwise you could use them as a small UPS. For a raspberry pi for Example...
I've figure out that this also depends on the voltage of the charger. If charger has a good cable and the voltage on the input port stays close to 5V my power bank doesn't turn of the load and indeed works like a small UPS. But if you plug it in a weak charger and the voltage on the input drops to say 4.5 it disconnects the load until fully charge itself.
Have faced this a lot in the past. But never tried working on this as I didn't need it too much and also got busy in work.
Some powerbanks have what's called a "Trickle charge" mode.. This mode forces the powerbanks output to always stay on. I've seen it being a thing on some of Anker's powerbanks, where you longpress the powerbutton and the indicator LED turns from blue to green...
You can just use an usb-c powerbank with a type-c breakoiut board, set both CC 5.1K to GND with a resistor to get 500mAh output on that port and keep all other ports awake with higher output.
What size are those shunt resistors (1206)?, you should be able to find or stack resistors rather than just unsoldering it, however the testing to figure out how to fix the shutdown problem is pretty awesome!
Keep em coming!!!!
Those are great! I love the pulse circuit! Ingenious!
had that shutdown problem once, and since then, I have bought power banks that support low current devices. With the Anker 737 I have right now you can hold the button down for a few seconds to lock on. And draw as little as you want.
Although he wasn't the first to make use of a 555 for this purpose. I recall Mr Carlson's Lab made a version in a video titled "Power Bank Stay Awake!" over 3 years ago.
I just replaced the momentary button with a self locking one
it kept the power bank on forever
the bonus here that stand by mode could be switched on or off 😁😁
The 555 timer ic makes a come back! 🙌
It's nice to see Scott using Everyone's Favorite Timer Chip in a project again. Coulda done it with a cheap, ubiquitous microcontroller, but where's the sport in that? (Seriously, as much as I love the 555, there's something to be said for a chip that only requires a bypass capacitor and a load resistor to perform the same function, and the micro could easily be heat-shrinked into a tiny USB pass-through dongle.) By the way, Paul Carlson built a similar 555 timer "stay awake" circuit a few years ago.
It still bugs me that power bank enginerds don't realize that many consumers need this functionality.
Should be considered basic functionality to charge something like a headlamp :/
It feels wrong using an entire microcontroller to just pulse a circuit though :/
As for power bank engineers, they do realise, it didn't actually take very long after low power type C devices like true wireless headphones came on the market for power banks to start including low power modes. The problem is that the cheap power banks just recycle the old designs so you usually only get these modes on mid to higher end ones.
@@bosstowndynamics5488 I meant the ubiquitous $0.03 one-time programmable 6- or 8-pin chips. Just a few lines of code to grab a brief pulse of current every few seconds, 100 nanofart bypass capacitor, appropriately sized load resistor, USB connector traces directly on the PCB...Bob's your auntie.
Funny, because i recently made exactly the opposite experience. 😄 I bought absolutely cheap beard trimmer for traveling. But this one had a) old NiMh batteries and b) an extra adapter. So i used a step down converter to the used 3V and an old USB cable to use it with a standard USB adapter. But than the charging always stopped after less than a Minute! I thought a made a mistake but than i realized that this only happens when the battery is full and the flow is dropping. Which is perfect because the original Adapter dopes not stop charging, so you never knew when the battery was already full. But because of the auto-stop of the converter now it does. So now i have a USB cable to charge and additional an auto-stop. Win-win. 😄
for these earlier power banks, you can put a switch on that resistor circuit, so you can get what most commenters are saying: a "trickle charge" or "low power" mode where you basically switch between the ultra-low power mode and normal operation, depending on your needs
I use the pulse method in a small circuit mounted on top of the 555 itself that I put inside the power banks and it pulses the output every 30 seconds for 1 second, and it works fine...!!! Great video.
A better option is another lower power piggybacked power bank of your own design. Just need to isolate and regulate output from charging input so as no over voltage or spike on the low power device at the very end of the chain! Just need to turn on the first in the chain occasionally to charge the second. Easy and less work. Simplest option of all: plug into a mains usb charger which won't cut out for low power devices! :-)
Also a problem with some small synthesizers. I found that some old small cheap powerbanks don't have a switch-off (ir it is very low). One soultion: using a USB hub and plugging in a USB lamp additionally. Then it stays on.
Great designs! I think the 555 circuit is plenty good enough for people that need the convenience of a powerbank. The "pre-made" power banks are meant for expedient use anyway so as long as it's not discharging the battery for nothing it's fine. People that actually care about doing a "most efficient battery powered IoT whatever" will just embed the battery and add a basic BMC in their device (ie the little boards that just protect the li-ion cells from over/under voltage and overcurrent).
Nobody should be getting a power bank and then try to hack it, just get a BMC board and cells and make a "dumb" battery
Great video!
I like the pulse circuit. Could dial it in to trigger right before the shut down of the power bank to minimize how much power is drawn instead of the 8 second interval used for demonstration. Maybe as a subsystem added to the small projects themselves to allow function with any power bank without external modules.
I know the current draw is quite small, but were there any voltage dips presented on the output side from the pulse?
I recently had that problem, thanks for sharing your solutions!
Thank you a lot for making this video, I was SO over with this feature.
Glad I could help!
Im sure I’m not the first one to mention this but most usb powerbank have two outputs, so you could put the timer in one and your application in another. It would probably be fairly easy to miniaturize into a tiny dongle.
IP5328 have I2C communication, u can easily configure this behavior throuhg it. First power on by button , to power the mcu, mcu sending "always on" to IP5328. This shunt 10mOhm it's for charging/boost current sense. I bet the whole IC get crazy after you changed it :)
If your just powering an ESP32 with the power bank then just use a bare 1s 18650 battery pack. The boost converter that steps the 4.2v to 5v does draw some power as in those aliexpress 3 for something .99 diy power banks.
Best DIY electronics channel on UA-cam.
If you cut the trace to the LOWER of the two current sense inputs and add a 1:10000 voltage divider, the measured current will be about .5mV higher than what it really is. No opamp required.
The only drawback is that the "amplification circuit" inside the chip may expect an about 10mOhm output resistance of the current sense resistor so it might be designed to draw a significant current. But I'd start out with a pretty high-impedance voltage divider.
At such a ratio the big resistor actually becomes "almost a current source" So you almost get an actual .5mV offset as you wanted. Try 1M/100 Ohm, if that doesn't work, try 100k/10 and 10k/1 ohm respectively.
My powerbank can actually be set to a "disable auto shutdown"-mode which also switches off any fast charging. It just provides stable 5V.
It's a ROMOSS Sense 8P+.
The mode can be activated by a double tap on the on/off button while it's on.
Ive been using that 555 timer to wakeup my bluetooth board for years. Never failed, works great and cheap.
You could also add a switch to bridge your higher value sense resistor with the smaller resistor for the times when you need to supply higher currents.
Use a shunt resistor that is 2-3 times higher reisstance than the one on the borad.
I've worked on a similar probkem, but my circuit can also be powered by standard 3.3V.
My sokution was to buy a DYI powerbank, female USB-C which i drilked a hole for, and a 1S BMS.
Connecting the 1S BMS in parallel to the battery connections on the powerbank cirxuit, and then to the female USB-C.
Now im able to pull directly from the batteries, without step-up loss, have some protection, and can be charged like a regular powerbank (using the existing connections).
I bought a power bank that has 4x 18650 protected button top cells wired in parallel and they are user replaceable with a slide off battery cover. I slide the battery cover off and insert the jumper leads to + and - bypassing the the electronic circuit board if I want to use with low power devices like micro controllers. It provides plenty of runtime for small loads, and if I want to be more exact with voltage or use maximum amount of power from the 18650, then I can plug a small DC-DC boost converter.
Thank you for the 555 schematic! I keep having this problem with older usb power banks I want to use to run LED lights with.
Glad to help
10:30 Couldn't you just use a higher value resistor, like say 20mOhm or 100mOhm?
Correct me if there is a flaw in my thought, but it would just lead to a bigger voltage drop, over the resistor, thus the IC thinking it is a bigger current flowing.
(Yes you would lose some Amperage potential in higher current application, say the circuit shuts off at 500mA instead of 1A due to our falsely increased overcurrent reading)
Oh.... Always love it, when commenting, feeling smart... only for the video to continue and him doing exactly what I was suggesting hahahha
A couple years ago I made a 3S pack using a cheap BMS board and a buck converter, put a toggle switch on it and wrapped it in fish paper (after I had an oops and had to replace the BMS board). Crude but effective. I did have to dedicate a power supply to it for charging with a current limiting circuit hacked onto it to prevent the supply from shutting down on overcurrent when charging.
This is a great succinct example of why everyone hates software and technology: A designer or company makes one assumption, and there will always be a huge number of people that don't want that as a feature. And thus nothing ever does exactly what people want
Did you consider making an additional port for your “ultra low power” projects, and using the normal ports for projects that you do want the shutoff protection?
The engineer who thought that shutting off the power bank if it does not detect 500ma is a id10t. Its in the same field as a cloud service for appliances.
500mA is quite big.
@@greatscottlab Agree it is a dumb circuit lol
Well these things were mostly designed for phone charging, and even old phones usually drew at least 500ma. Newer banks take into account that you might be using them for other things.
I experienced it alot, An led can also be used as a load for output spikes preferably an SMD one.
Or just force button press of the power bank to keep it turned on all the time using of course a signal instead of manually physically doing it.
I also go back over my sharpie marks repeatedly until it bleeds though the other side of the paper. 50-60% saturation is just not the same as 85-100%
Someone mentioned that some power banks such as those from Xiaomi can go to "Low Current Discharge Mode" by double pressing the battery check button (and exit by simply pressing the battery check button). This however, still has a potential problem that this mode will end in 2 hours. This may be good if you use it to charge your wireless earphones but in my case, I want to use the power bank to drive a water fountain for my cat (which draws about 40mA current, and don't have a near by mains socket) so I want it to be able to run as long as possible. Another question on Scott's hacks is, will the power bank still be protected from over-discharging, especially when the pulse circuit is added?
Yes the cells are protected against over discharge regardless, no matter that you apply constant load or wake-up circuit with intermittent load.
Except on the very cheapest of power banks, not reputable ones, which can only turn off boost but then the battery voltage is still on the output terminals, so instead of 5V something in 3V-4.2V range is present when it's sleeping. But you could say those don't have a functioning over discharge protection to begin with, sure a phone would stop charging, but LEDs, heating gadgets and other simple devices could overdrain such a power bank. You better check if you have those around.
You could probably just put a 10k or so(would depend on input impedance of course) resistor between the shunt and the VSN pin
I highly recommend big powerbank empty cases for 18650. It's the best case for DIY electronics.
- no need for hack like in video, just connect pin as input and u can read button pushes for custom special actions and every 10-30s set the same pin as output high for few ms to mimic single button push and that will prevent powerbank from turning off.
- dont use all 18650, take one of two less and put mcu there..
- cut plus or minus line from usb port and put mosfet in the middle and u have 5v line that is being controlled by PWM
- if u need more control then single button can provide u can remove LED and put pushbutton there (no need to drilling that is never perfectly centered so if have OCD u still be happy how project looks in the end)
- case for 8 cells (and u can put up to 7) costs only 5$ (cheaper then plastic case, usb ports and li-on charger separately)
8:47 Wouldn't it simply have been enough to short the "current shunt"? Then the 5V would just pass through or not?
The controller wants to see a small voltage drop. Too small and it thinks there is no load (must shut down after a while to save power). Too high and it thinks the load is too large (must shut down immediately).
@@tomasburba5356 thanks for explaining!
5:11 As a newbie to electronics can someone in layman’s term explain why on the output Vcc is connected to GND 🤔. Listened through a couple of times and seemed to have missed something. TIA
The shunt resistor mod gives me an idea... what about a voltage divider on the 555's reset pin, carrying (or transistor buffering) current? Pull RESET low when current exceeds a certain threshold, so we're not unnecessarily pulsing the load when the attached device exceeds the minimum draw. Might be useful for something like a remotely deployed ESP32, where it''s mostly idle, but occasionally has a bunch of Wi-Fi connected work to do, for example.
Why should solution 1 (USB-C Powerbank with power delivery trigger board) deactivate automatic power off?
I work mainly with phones. For example, just by the current that the iPhone draws, you can tell what is damaged in it. I have a 20,000mAh and 20W Powerbank from BaseUS and it drives me nuts when it turns off after 15 seconds of no or low power consumption (around 0.05A). I was thinking about making a PCB for it to artificially consume power, but I put it off until later. Btw my old Xiaomi 10 000mAh Powerbank with 5V2A output supports low power mode by simply clicking power button 2-3 times. Then it will never turn off, but I can't always use it, especially when I need Fast Charging. Thanks GreatScott!
The IP 5328 chip is programmable, granted it only mentions charge curves, but probably also has provisions for setting the auto shut off value. Using TP4056 and a 18650 cell we bypass the cut-off problem altogether. And while the TP4056 draws 20µA that will take awhile to discharge with no load attached.
Cool video. Could you do a video like this for battery powered bluetooth speakers? I have a similar problem, it seems. I have scoured the market for a decent portable battery powered speaker that I can use as a speaker for portable keyboards/groove boxes. I don't even care about the BT functionality, I just want the ability to plug a headphone cable out of my music device and into the aux in of the speaker. The problem with this is that every speaker I have tried seems to have a similar auto-shutoff so if I stop playing even for just a few moments, then the speaker goes to sleep and it takes a few strikes of the keyboard to wake it up again. I wonder if if this has a similar solution, where we can remove the autosleep altogether, or perhaps send it a subsonic or supersonic audio pulse at regular intervals to keep it awake. Of course if it is an outside of case solution, I don't know how I would power the thing that creates the pulse.
i faced similar issue to power up my lcd clock from a power bank which would turn off in a minute due load current of less than 1mA, so i made a bms with a boost circuit to 5V which never turns off still working great.
My power bank (A+) stays on if I periodically press the button. Maybe a 555 timer that periodically mimics a button press would work and would be very efficient. I don't know if it work on all power bank tho.
One thing I would like to see is a low voltage input cutoff on powerbanks. I have several that will draw all the way down and not shut off when they get low.
I don't like the batteries going that low. Luckily I'm using recycled laptop batteries that were free. They would last longer if they didn't draw down so low.
6:52 *Wiggle connectors up/down or side-to-side like this when you want to have them wear out prematurely.*
Of all the options you provided, I liked the one that gives pulses the most
The venerable 555 still being useful!
Assuming your project has microcontroller you can use it to time pulses to load thus skipping 555 timer circuit entirely
Could you please add a link to the USB Power Delivery trigger board. Its sadly not listed in the description.
Well thanks for not answering... :-/
0:47 I love these ones, and upgraded one with type c 10W charging.
low power mode can be activated on majority of branded powerbanks.
the real problem is that some powerbanks may turn off after charging your device instead of acting like a wall charger (until power bank drains).
Why not add a schottky diode with a resistor in // in series to the shunt resistor?
Yay for the 555.
Useful in 1978*
Still useful in 2024!
* Marketed in 1972. But I was using it as a kid a tad later 😅
Think the cmos version came out in my youth too...
Hi love all your videos. Anyway you could hack a power bank to become passthrue power bank (like having usb camera that can stay on after powr failure or evan Rasberry PI) without the need to buy ups?