Fancy 1-8 cell lithium battery level indicator
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- Опубліковано 15 вер 2024
- This is the more sophisticated battery level gauge than the earlier op-amp based one. It uses a microcontroller to do the level testing, and has solder-blob links for selecting from 1 to 8 cells.
The design is refreshingly simple with a selectable voltage divider for different cell counts, and all the threshold detection done with software.
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/ bigclive
#ElectronicsCreators
That's exactly the one I mentioned in my comment under the other video.. the 1S mode only works right if you bridge the protection diode out, otherwise the whole module dims away below 3.5V instead of showing fewer bars than 3
One thing that the mfg could've considered was making the battery outline have a 1Hz flash rate when the final battery bar was cut out for being below threshold and serve as a indication to recharge the battery.
If the microcontroller is flashable it would be a trivial matter to reprogram it to do that even if you had to start from scratch after erasing it.(Assuming it has copy protect enabled)
Actually, it would probably be easier to erase it, rather than trying to decode the assembler listing. Depends on what type of language they used to write the source code.
You'd also have to rewire the red LEDs to be controlled by a spare pin on the MCU.
@@kimchristensen2175 In my experience, the sorts of chips used for these sorts of applications are usually mask ROM or OTP, not reprogrammable. Even if it was, though, you'd need to know all of the details of the instruction set and chip architecture, which are quite possibly very nonstandard. It's probably not feasible without getting assistance from the company who makes them (who likely aren't interested in talking to anybody who's going to be ordering less than a few million of them at a time).
It also might well not even be a microcontroller at all.. It could well be just a circuit similar to the other comparator design, just with everything prepackaged into a convenient chip...
@@foogod4237 Could be. Looks like the pinout is close to one of the 12F or 10F series pics. I guess it could be swapped for one of those, but that's probably not worth the effort.
Can this be modified to work on even higher voltage batteries?
@@data9309 I'm sure you could. You'd have to add a higher voltage rated pre-regulator ahead of the existing regulator or replace it with one rated for a higher voltage. And you'd have to modify the resistive divider to scale it properly to the higher voltage.
Very nice...definitely better than the other one IMO
actually a simple and robust circuit out of China. I'm impressed, esp if it's at a good price point
@@pauls5745 They only cost about 12AUD for 10 incl shipping. Pretty damn cheap.
Thanks Clive, always great to see and hear your investigations of the electronics out there.
So frequently now I pull the lever on my easy chair and let you teach and entertain---that's relaxation!
Happy New Year, many thanks for your easily digestible material. senior from Canada
Totally agree, and Clive's soothing voiceover is just made for sipping whisky at the same time, but this can lead to missing the finer points of 'sschematic' analysis.
I was frightened by circuit, but when you explain it, felt so easy.
Thanks
perfect for a project I'm working on right now... thanks Clive!
Nice little item, I like the display its big for older folk to see. 🔍 great video 2x👍
I love your videos Clive.
Looks like they are keeping 1.5 low to 2.1 volts max charge on the ADC pin. Hope people read the instructions before using more than one cell.
Nice a Clive video just in time it Looks pretty neat !
I like this one, I shall have to go and buy some! There is another very similar battery indicator with more complex circuitry than either of those you have reviewed so far, it's based around a 14pin MCU and can only be bought preconfigured for batteries in 1S, 2S, 3S etc. I'm sure it can be reconfigured by changing something as simple as a resistor on the board.
I was just thinking the same thing - An A to D and a bar graph LED for £ 1. 5 , from Amzon UK and 1 resistor sounds useful
@@kit-geoffbullough8788 If you don't mind waiting they're only about 50p from AliExpress.
Really nice! I like the configurability.
just used my first recycled vape lipo thanks to you. Stuck it on an esp32 with a neopixel ring and flashed with wled.lasts a good few hours on 50% brightness :) Next vape i find Im going to make my newly acquired novelty desktop henry, rechargable usb-c lol.
I like the idea of flashing the cell when >= 4.2 V. The only issue with this might be when used as a charging indicator, the voltage goes a little bit above the actual cell voltage, especially if there is a wiring voltage drop out to the physical cell location, which could give a false warning.
IVE BEEN LOOKING FOR SOMETHING LIKE THIS FOREVER. I build custom guitars and my signature thing is putting a rechargeable battery in the guitar chargeable via type c directly into the instrument. Would LOVE to have a indicator built into to the back of it!!!!
Your comment on flashing for overcharge depends on how they're referencing the ADC. If they're using a Fixed Voltage Reference (literally the FVR in PIC land, either 1.024V, 2.048V or 4.096V), then if the ADC input exceeds that reference, the ADC reading will just saturate and be pegged at (2^n) - 1, unfortunately losing that overvoltage detection.
Having said that, I guess a competent designer would've sized the potential divider to not use the entire full-scale range, thus allowing such a saturated reading to be handled in software... Maybe they even did that and were just lazy and skimped on the animation... I guess we'll never know.
Well, looking at 8-cell, with it at 33.6V full charge its at 2.1V on the ADC input. So they picked the 2V reference, and it will already be saturated before it even hits full charge.
@@clynesnowtail1257 Mega, thanks for doing some maths for me, apparently I was too lazy at the time? 😂 I guess same goes for the single cell as well, right? 4.2V into a 10k / 10k divider would give 2.1V into the ADC, and same thing happens again.
Well, the issue with not using the full range is that you lose accuracy, and given that you'd want to be looking for something a bit over 4.2 V (single cell) for "saturated," you're then looking at covering 50% more range. I have always wondered how accurate these ADCs are; would using only two thirds of the full range for the "non-overloaded" levels make the accuracy significantly worse? Perhaps not, in an application like this....
@@Curt_Sampson Not sure I quite follow what you're saying. In the case of this module, the full range of the ADC is (probably) 0V - 2.048V (using an internal reference, called an FVR, inside the microcontroller). By using the FVR, you no longer have to worry about the supply voltage of the microcontroller affecting the ADC measurements. For a fully charged cell at 4.2V, being fed into a resistor divider made of two 10k resistors (the 1S setting on this module) you get 2.1V fed into the ADC. 2.1V > 2.048V so percentage wise, you're attempting to use 102% of the range. Due to how the ADCs are physically built in the silicon, this will be 'constrained' to 100% of the value. Thus, even if the cell was sitting at say 5V (grossly overcharged), the ADC would see 2.5V, but the digital conversion would still read the same as if the cell was actually at 4.2V (providing a 2.1V input) since, in both cases the ADC is saturated.
Regarding accuracy, most micros of this type I'd expect to have at least an 8-bit ADC. 2.048V / 256 steps = 8mV/step. Scaling this value UP by the ratio of the resistor divider gives (for the 1S divider) 16mV resolution across the cell. Presumably that value is pretty much constant in terms of a 'per cell' error, assuming all cells are at least roughly balanced.
EDIT: ADC saturation doesn't necessarily equate to device damage.
@@adzib1823 I think your 2.048V hypothesis is flawed. The natural output voltage of a band gap reference is about 1.22V. Any other reference voltage is likely to demand individual device trimming.
Many cheap microcontrollers with ADCs, for example the ATtiny5/10, tie the internal reference input to Vcc and let the designer worry or not about a clean supply rail. PIC12F609 isn't much fancier, offering a 1.1V band gap and a 4-bit digipot between the supply rails, the latter borrowed from the comparator module. That's plenty when you have a regulated supply rail and don't need great accuracy, or you are using the common idiom of a pot between the rails as a physical control input.
Using one with an 8way cheapy PCB mount slide switch to make a simple 1 - 8 cell selectable lipo battery tester. So handy, when you can put it in a box with different battery connectors to just plug an test. 👍
I just watched the other vid 2 days ago. very vids again sir :) neat modules.
It's my birthday today and my personal battery level is definitely at half these days with some serious parasitic drain!
My birthday as well. Happy birthday.
Happy birthday to you both.
@@bigclivedotcom Thank you Clive 😊
Wonder if it is multiplexing the green led bars, given 1 resistor for all 4.
The intensity seems unaffected by how many are on, suggesting they are doing it.
In the "features that would have been nice" category, I'd put a DW01 or something like that to kill the circuit if the voltage drops too low. Those red LEDs could easily pull the voltage below 2v.
I know more than I need to, today....
Thats what makes tomorrow fun.
Happy News Year BigC. xo.x.
Nice looks good for projects where you need to be able to see the battery level at a glance or you probably could wire in a momentary switch and use it as a checker on projects but then you'll have to hold the button down but it may be better that way depending on you application
Very handy indeed.
'potentially being overcharged'. love it.
Excellent presentation.
Brilliant bit of kit I have a use for one of them thanks Clive
Very similar to what I did with an Atmel TINY85 microcontroller. Used Green/Yellow/Orange/Red LEDs is sequence to indicate the state of charge of a 3 cell battery pack running a Raspberry Pi, and with a critical low charge output to initiate a graceful shutdown of the Pi.
I think that the voltage divider could be slightly easier and cheaper to manufacture if the top row of the resistors would be in series instead of in parallel. This way it could be made with a 10k resistor and a bunch of 20k resistors or even with just 10k resistors instead of a bunch of different resistor values.
I always like a good schemematic.
It seems simple enough. Happy New Year! Good luck.👍
Thanks, Clive 😁
Cute! Might buy one myself
Neat. I'm really tempted to get one of these and slap a set of different sized connectors typically used with lithium cells on it. Maybe there's even a way to get a rotary or sliding switch for the cell selector… hm…
Would be fun applying the LM324+LM431 design to this initial set of parallel resistors. Real fun is getting a high enough LM324 supply in the single cell configuration without getting too high in the 8 cell configuration with 8x4.7V on the input. Maybe it would need to underpower a 5V regulator.
Thank you so much, i was trying to find something like this
Happy New Year Clive.
Happy new year, Clive! I've just backed you on Patreon.
Thank you. It's greatly appreciated.
@@bigclivedotcom no worries. It is a pleasure to be able to support someone as cool as you. Your videos have taught me a lot.
Neat unit. I bought three. Identical except the V regulator is a 7133. 3.3 volts.
I’ve used them in a model boat that gets quite a lot of condensation. So painted on conformal coating to help.
But so far, after about six outings, I’ve had two fail. Using them on six cells. Lipo.
V regulator and the micro have blown. Dunno why yet. Spikes when I connect the battery ?
I have one left. I’m thinking maybe I’ll increase the value of the current limiting resistor (560R) to reduce the current
through the micro when all bars are on ….
The bars are very bright so should be ok …. we’ll see.
Thanks for the video. 😊
And A happy new year to you sir 🥃👍
I have one that can measure up to 8s lipo, showing voltage display scrolling via 3 7 segment displays and can warn (very loud beeper) if battery voltage is below a set voltage, I would love to see it back engineered by you Clive. Great Video as always thanks.
I think I might buy one or two of these little devices. Thanks.
I don’t understand half this stuff, but still love the videos. 😂
Another neat trick would have been a brightness selection (bridgeable solder pads) I have a few in my bluetooth projects and for indoor lighting these things could do away even with 40-50% brightness. Do you reckon replacing the 560R resistors with a 1k or 2k ohm will do the trick or would it interfere with the calibration/settings.
Anyways, great video as always C.
You should be able to change the LED resistors without affecting the calibration.
I was surprised the other unit with quad op amp and lots of SMD devices wasn't a simple microcomputer like this. It makes me wonder on cost. Can a quad op amp and discreets be less than a micro (especially a three cent one)?
I was surprised to see a common resistor for the LEDs. For regulator power you have to include the LEDs, so seems like the few milliamp is with no LEDs on? Or else they are very low power too.
And that's fine, if your resistors are in specification, I had one similar and not one of the resistors put in the board werewhat was marked on the board itself, as a result it was 30% off, I changed every single one and now its within 5
I bought some of these exact ones off of Ebay, there was only the 2 wires for connecting only one battery and they were all being sold as a 3.7v 18650 battery meter.
Certainly a bit more useful with the options for different battery pack voltages on this module... :P
I do like the option to change
I usually just lick the end to see how full they are - tend to be a bit floppy if fully discharged.
Thanks for the video. I saw this battery level indicator, or something very much like it, on Think Robotics' website with SKU ELC2003. Did you get that indicator from Think Robotics?
I can't help noticing that there is one apparently unused pin on that chip, which makes me wonder if the IC itself might actually have some extra functionality which just wasn't actually implemented by this particular board. It would be interesting to monitor that pin and see if it does anything interesting as voltages change...
Happy new year dood…………………
5:47 Did you try? The micro can't see which programming resistor is connected. I bet the chip is just a 2.1V bar graph with a big offset.
And of course, one can be clever and use parallel combinations of the resistors to work with other types of cell like NiMH.
There is one problem here with the indicator : The LED s are continuously on whether you are charging or discharging the battery.Which means,even after unplugging the charger, LED s will be on draining the battery. Do correct me if I am wrong .Thank you .
So the LEDs can be utilised individually with a separate microcontroller, bypassing the onboard one, by utilising the numbered LED cathode pads?
I think you can get the bare LED displays.
@@bigclivedotcom Seems rare, I have searched by that part no SPBK(x)S-10, x supposedly color variant, all of those come pre-assembled.
They look nice and have a good form factor, I would like to use them display capacities for stuff other than batteries! I think i will buy a few and try feeding those pads or ground them to find out. Thanks BigClive🖖
"Hey... Who turned out the lights?"
With the single shared 560R for the four bars, does the brightness change noticeably with the number of lit bars? Or is the micro-controller actually only lighting one at a time so that they each see 25% duty cycle, regardless of how many neighbours are lit?
Reminds me of one of those LED 7 Segment displays.
Now I can add this feature to the lower grade Ryobi One packs..
The Clive, I have a question, when you have a discharge resistor across a capacitor, does it not almost entirely negate the effect of the capacitor, so much as to be useless, or, could not a lower value be used in its place, or, if one is used early in a circuit, should not an inductor be placed somewhere after it to maintain any dropout which might be caused by said resistor 👀 or am I being stupid
There are many applications that use a resistor across a capacitor. It still has a "storage tank" effect to give a stable voltage.
@@bigclivedotcom I sense a but, there...
BC: You mention a missed trick in displaying an overcharge condition by blinking the 4 bars. How would the schematic change to allow for this or would it be done with software in the MCU?
It could be done entirely in software.
Idea for future video. To tear down "analog" LCD tablet with clear button. It has a little PCB inside with voltage booster that clear the LCD. I couldn't find any video of any of them disassembled.
I opened mine because the button stopped clearing the screen, even though the battery voltage is ok. Turns out it exceeded battery current capability (~15mA) when spiking voltage.
To open the device the screen has to be simply pulled off.
The red should be over charging since the battery pack most likely will turn off anyway when under voltage is reached and it does not reach 36v then?
I bought one of those and a 3s bms for use in a 12V lithium pack, does that mean I have to "short" the 3rd resistor to tune it for my pack? All I need now is a good DIY spot welder, got any idea/video showing how to and not to build one, I really would like your advise on that one Clive.
Ps. how much power do that indicator use and should I put it on a momentary switch to avoid the discharging?
Well, if it was smart enough, it could do that with only one voltage divider, even if it was speculating a bit, but detecting SoC based on voltage anyhow is guesswork.
Edit: Anyone remembering Basic Stamp? And how it used a single slop measuring technique to measure voltage with a single pin and a timer? ADCs are expensive!
Could be changing colors based on the number of cells also, even smarter! hmmm...
Happy New year Clive, will you be getting the ones that display a percentage instead of 4 leds next ???????? :-)
What happens if you bridge two pads, say the one and three position?
It will give an intermediate voltage threshold.
nice. thank you
Are you certain this will work on Lithium batteries? I was lead to believe they give a linear voltage output until they switch off, unlike agm/lead acid?
I think the led is OK. I could be wrong but I think I had a batt charger that hat a LCD bargraph maybe you can get one of those to show off. Might of been over 5 years ago on the energizer aa charger. I don't think I have one at the moment. But I did make a big version for arduino on someone programmed code on the display.
A universal version would have two potentiometers to set high and low thresholds.
can these be wired upto a battery continuously ? or can it only be a "checker" under no load ? (correct for terrible grammar)
It would pose a slight current draw continuously.
Cool 😎little module 👍🇮🇪💚🙏🏼🔋
[Clulow (pronounced /klo͞o/ /lō/ "one low in clues" but not clueless)]. Interesting and educational analysis as in all BC Videos. In my projects, however, I prefer the modules which display numeric voltage / pushbutton to activate. Perhaps this module might find use in a consumer product where a "dumb" SOC indicator is a good option. But I cannot imagine using this, unless of course I were designing a circuit for the future me wherein I'm finding it difficult to remember how to turn on my computer.
Hm, no cap(s) close to the regulator? That might give it a nice swing.
BTW, datasheet says 1microF in input and output.
Nice update compared to the other one.
But which has the lower consumption?
Is this the up-date to those batteries that had a button on the side that when pushed perported to show how much charge was left? Did you ever "Do", one of these?
I did make a video about the duracell battery indicator.
Would it of been possible to make one with a 2 digit lcd display to display it in a percentage?
They probably exist.
I've always hated the way the actual indicator looks. I put bluetooth stereos in weird things. That sci-fi battery rarely matches aesthetically. I could probably use this and port out my own LEDs... duh.
Any idea what micro controller these companies use? I am working on a project and am using an ATTiny85 and wonder if what they use could be better or cheaper.
There are many cheap microcontrollers like Padauk chips in mass produced products.
@@bigclivedotcom thanks. As I mentioned I have a big project coming along and cheap microcontrollers might come in handy.
Just checking the voltage of battery without load cannot indicate battery capacity. Share any true battery capacity indicator if you know.
Surprised that they didn't just use 3 jumpers. binary for 0-7 (Number of cells - 1). Would have had the same encoding with fewer parts and no likeliness for bad jumper combinations.
Super bro 👍
#TheProjectLab
Could you check out the "HW-586 Capacity Tester Meter Li-ion Lithium Battery" .. it is just a couple bucks more but seems to have so many more features like capacity testing and such.. ;)
I've actually had one sitting here for years. But never really tested it properly.
What would happen if I connected this meter to the battery and then starting charging it what would happen? Could I see it filling up?
Yes.
Some linear voltage regulators aren't so... Linear. Some of them are just a poor man's switchmode power supplies within the tiny packages. Obviously a true SMPS voltage regulator now exist in the same transistor package as this voltage regulator on the battery life indicator, with all the whizbangs on a single die - some CPUs have the same stuff on-die nowadays due to the differing logic voltage islands such as CPU Vcore rails (Intel is one of the companies that makes the processors with built-in switchmode voltage regulators).
How to configure this module for 7s connection should we short at 7s
If it's that type then shorting the 7S link should work.
Possibly not so useful for LFP (Lithium Ferro Phosphate) cells? They don't seem to be easy to gauge the stored capacity based on voltage and systems have resorted to measuring the inflow / outflow currents and setting the high / low tide marks when hit. Obviously smarts with persistent memory are required for these. I believe this is why some people are running their cars flat and then fully charging them to "retrain" the BMS as to the total capacity of the battery banks.
Took me 3 minutes to realise my phone was displaying the video upside down.
I wonder if you could wire it to an 8 way switch so that you could adjust it depending on how many batteries you wanted to charge in a multi bank charging rack
Theoretically, yes.
@@bigclivedotcom I have a 7 bay charger but it has an LCD display showing percentage . I have itchy fingers to get the screwdrivers out now 😂
Just like the one I use on my photon cannon 😂
How to hack it to use as car battery voltage indicator?
If it was me I think I would have had a transistor on the last o/p that actually switched the red outline on when the battery was flat!
No transistor needed. It could probably be done with the spare pin on the microcontroller.
@@bigclivedotcom Yes but you would have to re-program for that, vs a couple of discrete components...
Its a shame that this battery level display unit doesn't go up to monitoring 9 cells at 36v dc which would be quite a common battery pack voltage, unless you can modify the unit to do so.
If used for brief tests on a balanced system you could tap it off just a few cells to get an indication of the entire pack's charge status.
Do you have a link where can these be purchased?
I got it from a local eBay seller.
Anyone have a link of where to buy?
Any chance of an affiliate link Clive so you can make a few pennies on my next purchase?
Personally? I'd reserve the red background for faults, then use chasing LEDs on the meter to indicate what the fault is. Chase upwards means overvolt. Chase downwards means undervolt.
Red, after all, is what you want your warnings to be, and you have a micro-why not make it a little _more_ fancy?