1) Watched video 2) Downloaded manual for my charger 3) Saw balance current rated at 200mA 4) Slammed face on desk 5) Bandaged face 6) Started shopping for new charger... Thanks, JB! I didn't even know I needed to learn something today...
@@lnteI I doubt that. You'd have to change the software as well. Also, mine's only 500mA balance current per cell as well, but it charges my battery quite quickly. Probably because I have a pretty good battery that isn't really out of balance. All of this balance current only matters if you actually have batteries that have differing internal resistances - either due to age or simply the quality of the battery itself.
@@Vousie Most likely firmware is just checking the voltage on each cell and stops charge /activates discharge while one cell is full, i don't think it checks anything else except the actual voltage on each cell. Once voltage drops to the required level, discharge stops and charging activates. If this is as simple as that then changing the resistors / fan would totally work, I may sacrifice my charger for this project
The straw analogy makes so much sense now, and the sucking sound just makes it so much easier to understand exactly how the stored energy leaves the battery
Note: some manufacturers and retailers (like ProgressiveRC) use the term "Current Drain (Balancing)" to list what you refer to as 'balance charge current' - their terminology is more accurate than yours since the full cell(s) are actually drained when topped off whilst the other cells are being charged. On my 4010Duo, for example, it is 1.2A and 2.4A). BTW, the reason battery balancing of cells works this way is simply cost and safety. Rather than maintaining 4, 5, 6 or more charge paths (or whatever S rating your charger is), each needing to carry a non-trivial amount of current as well as sense circuitry to monitor voltage, it is easier to just dump energy into a an R-bank per cell.
Hey hey hey JB!!!! You can't just look at the current. You MUST look at the POWER you can discharge. If you have 6cell you can't use the entire 1.5A in your case. Say your battery have 25V, you can only discharge 0.6A. 15W/25V=0.6A, looking at the charger in this video. I have chargers with a maximum discharge of 5W, really low current when the voltage is high. The same goes for charging, maximum watt. Higher voltage the lower the current, and vice versa. Thank you for great videos. Keep up the good work informing the comunity.
Hey this is Joe's wife, nice video. I love the time and work you take into explaining how things work. Especially from your point of view. I'm a big fan. Hugs. Much love
Great video JB. Just a small clarification, Most chargers start balancing while charging, they dont wait till the end, before the battery is full, the cells are already balanced so they reach 100% SOC at the same time. Also, the charger doesn’t “suck” current out of the cells, it just shunts the charge current past the full cell. If you put an amp meter on cell, you will see that no current flows out of it, if it did, the cell voltage would go down, and it never does, it reaches 4.2 and just sits there.
The cell voltage stays the same because the charger is sucking charge out as fast as is being pushed in. The charger can't "shut current" past the cell. The current is pushed into the pack via the main discharge lead and fills all cells equally. If the charger was capable of "shunting" past a cell, then balancing would be just as fast as the main charge cycle.
@@JoshuaBardwell JB, current can only flow one way in a conductor. U can not have current flowing both ways simultaneously. One cancels the other, and no current flows. I can make a simulation schematic showing what actually happens. If current flows in or out of a cell, the cell voltage will inevitably change. Put an amp meter on a cell, and see it happen. At the end of the charging cycle, the charge current will exactly match the balancing current of the charger. Test it. Trust me, at the end of the cycle, when a cell reaches 4.2v, NO current flows through the cell. It flows through the internal resistor bank, past the full cell. This is called current shunting.
Correct you cannot have current flowing both ways in a conductor. The current goes into the main discharge lead and comes out the balance lead. I have verified this with a clamp meter.
@@JoshuaBardwell right, so if the current flows through the main lead, then out though the balance lead, then it doesn’t flow through the cell, does it now?
@@JoshuaBardwell i am on a phone right now. When i get back home, i will make a circuit simulation, showing exactly what happens. But the short of it is: the charger shunts its own charging current through its own resistor bank. And no current flows through the cell, from the cells “point of view” is like nothing happens, its as if it was completely disconnected from the circuit. I know its a bit tricky, but thats what the charger does. This is exactly why, when the charger is balancing, the charge current equals the balance current. It is the SAME current.
It's not only balance current that matters, but also algorithm. Old IMAX B6 works like Joshua describes. I was pleasantly surprised that ISDT charger starts balancing long before cell is full, therefore final balancing phase at the end takes just seconds.
Regardless of when the balancing occurs, it can only occur as fast as the balance current allows, so it adds to the charge time either way. Possibly it's better to do it in the Constant Current part of the charge vs. the Constant Voltage at the end.
@@JoshuaBardwell But regardless of how high a balance current your charger is capable of, it only matters if you have very unbalanced batteries... Which you may not have if you are using reasonably new & good quallity batteries.
icharger 406 Duo FTW! 40 amp discharge per side 70-80amps if you combine both channels also can do regenerative discharging into my 2x120wh deep cycle batteries, don't buy cheap, spend extra and buy 1 time, have had this thing for years and it's freaking the best even has sd-card logging!
Like you said, I’m gonna learn something today. Not every day, but today I did! I’m actually in search of a charger that will do 5000 plus mAh 6s packs for my boat and my quad so That’s going to help me in my decision making of the charger tremendously. Thank you sir. 👍👍
Actually this video is somehow misleading. All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V. So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery. And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
How did you get so smart? I'm mean... My entire life people came to me for answers and yet when I watch your videos I feel like a student that doesn't want to leave class. Freaking amazing!
He isn't as smart as you think, he believes in NASA and if he would watch this he might have a change in heart ua-cam.com/video/itCwbKUy6TM/v-deo.html its NASA's origin story. And its jaw dropping
1. Most chargers probably charge over the discharge leads mostly (and discharge slowly over the small balance leada) because you can transfer much more current over the big wires without overheating the wires. 2. Is the diagram correct/consistent? Should the cells with the lower resistance not also charge up at a higher rate, reversing some of the imbalance?
I wondered this too, but I think because their resistance hasn't changed between being discharged and charged, then the input difference would be the same as the discharge difference, and it *should* reach full at roughly the same time as the others if all cells charge and discharge at the exact same current. I'm only speculating though. I also wondered if the charger will get slower and slower for each cell that is full, or if the charger can pull that rate out of every cell simultaneously. I see that the charger info in the video said 1.5A per cell balance rate, but do they all work like that?
Explained this so well, I have cell imbalance on 3 x DJI TB47S batteries, just need a video from you now to explain how I can bypass the smart charging circuit board on those and start properly balancing my cells. Keep up the great work
Balancing is also charger dependent, some older chargers had their own dc-dc on the balance lead so it could discharge one cell and charge right into another cell with the power rather than wasting it, also allowing charging of single cells while balancing. Most balance chargers merely shunt a resistor across the cell(s) to only discharge the cell. The dc-dc per cell was much faster at balancing as it avoided most discharging of cells when done.
Great video as usual! I only have one charger that charges through the balance plug, and it is only for small 2S batteries. That’s OK because small batteries don’t need much current. If you were to charge a larger battery (or parallel board) through the balance plug, then the current rating of the wires and the JST-XH connector could be a limiting factor. So that’s another factor that may encourage manufacturers to use the main discharge lead for charging.
I’ve got a charger that charges from the balance lead and charges at up to 4 amps. It’s nice not needing a lot of charge adapters but I think it’s more efficient at charging.
@@habenero_fpv that is surprising. The JST-XH connector is only rated for 3A continuous. datasheet.octopart.com/XHP-4-JST-datasheet-8325564.pdf We often exceed the recommended current on connectors in flight, but that is for a short duration with extra air cooling. I would expect a charger to be more conservative on the ratings.
@@MrShutterBug it’s not continuous, and my balance plugs seem to be holding on. Checking the specs and it charges up to 4 amps and balances at 1.5 amps. It does all this thru the balance port.
please give the full specification of the discharge resistor that you showed. I tried setting up my own rig like this but the resistors heat up too quickly. I have been discussing this in the ELRS Community discord in the ganeral-quad-help channel . I have reached the point where I don't know what move to make next. cheers
There are really two issues in balancing charging. One is variations in internal cell resistance (as you mention). But balance current doesn't help with this. The only way to handle mismatches in cell resistance is to slow down the entire stack charging rate to prevent exceeding max voltage on the most resistive cell. For this, the role of the balance leads are to measure individual cell voltages. The second issue is differences in cell capacity. Even with perfect manufacturing, cells lose charge capacity at different rates as the stack ages. This is where the discharge current comes in. The charger must allow some of the main stack current (which goes through all the cells) to partially bypass cells with lower capacity. The big slow down you have at the end of the cycle includes both of these effects.
That is very interesting I have never heard this mentioned before. I now understand why the Hitec X4 (300 mah balancing) took forever. I quite flying three years ago, still enjoy the videos.
Only thing to watch is whether the balance current quoted in the specs. is total, or per cell. "1600 mA" (for example) sounds good, but on a 6S charger that might mean 267 mA per cell (1600 / 6). Another charger might quote "250 mA" for the balance current, which sounds pretty puny but if that's per cell then both chargers could basically be the same.
@@guarf for that charger (I have one myself) it's up to 1600 mA for each of the two outlets ... but it's unclear whether this is a fixed 267 mA per cell, or whether you'd get (say) 800 mA per cell if you were charging 2S, 533 mA per cell with 3S, etc.
Less charging voltage = more current drawn and a hotter charger. The inverse is also true. More voltage will shove less current into your batteries faster and cooler, but don't take that as any information to act on. My B6 charger was an illustration of that basic electrical premise as I wondered why I had to replace a melted barrel connector. 16 volts instead of 12 solved that issue.
On the subject of balance charging, as an experiment I made a very simple 2S charger that runs off USB 5v and fully balances the cells, because it charges them individually, at the same time. How? Miniature 5v DC-DC isolation transformers is the secret ingredient - you put 5v in to two of the pins, and you get 5v out of the other pins, but the output is completely isolated from the input. Basically: 5v goes into a LTC4056 1S lipo charging board which is then connected to the first two pins of the 2S lipo's balance plug. But you can't simply connect that same 5v source to another LTC4056 and connect it to pins 2+3 of the lipo's balance plug because you'd be shorting out the first charger board and the first two pins of the lipo. So you drive the 2nd LTC4056 from a 5v DC-DC isolation transformer, preventing any shorting. Slow? Yes it can be, but you do end up with a properly charged 2S pack. If you add another isolation transformer & LTC4056 you can charge a 3S that way too. But I'm not recommending anyone do this, I just did it out of curiosity.
I already had idea about balancing current as main culprit why my old trusty SkyRC D100 charger charge batteries to brim quite fast, but balancing continue for another 20-40 minutes. Especially for used 4-6 cell batteries at end of season. Turned out that thing have only 300 mA balancing current. Already decided to buy proper charger with built-in AC power supply. Update: Purchased HOTA D6 Pro a week later. With 1.6A balance current charging now ends much faster.
The graphics and sound effects are making me uncomfortable. Another thing to consider is that some better chargers will discharge the higher cells as soon as they begin charging rather than waiting til the end, which will make it much more effective, but a higher balance current is still beneficial. Also, the reason the battery seems to slow at the end is due to the CV portion of the CC/CV cycle, so even though the voltage shows ''charged', it is being pushed to that point and held there, and will drop down if the charge is stopped at that point. This is also why the current drops at the end, as during the CV phase the charger maintains the set voltage and just supplies whatever current that causes the battery to pull.
It legitimately took my charger 27 hours to balance a 4s 6000mah li-ion battery that I forgot to balance the cells before assembling it. Balance current definitely matters!
So is it safe to say that a charger that can do 200watts at 25amps with a balance current of 400ma is slower than a charger that does 150watts at 16amps with a 1.2amp balance current.???
Would you be able to do a video of testing all the different capacities of a 4 S and 6S batteries and graphing the respective flight times. E.g for 4S: 1200MaH = 4mins, 1300MaH = 4.5 mins, etc so that we can see when the weight is no longer beneficial on a standard 5” quad!
Josh as always great video, I have searched youtube with no success maybe you can help me, and a thousand other retired seniors that are not so computer savy! I have been flying fixed wing for 40 yrs and a couple yrs ago i got a tiny whoop and have progressed to doing a small amount of tuning with some success because of you and your how to video's, recently I discovered the DJI mini 2, I want so bad to buy one but I know absolutely nothing about recording anything to a micro disk much less playing it on my computer (chromebook) and it would be even better if I could share a video. Believe me when I say there are a lot of us in need of someone to take us by the hand and lead the way, of course I think this would make a great series of video's for people like me who want to but just don't have the know how. Thank You Josh keep up the good work.
VENOM!!!! GD VENOM!!! I have that $270 4 bay big boy! First and biggest one I could find that had the best specs that I could find...... come to find out it TAKES FOOOOOREEEEEEVEEEEEERRRRRR TO CHARGE any ANY lipo new old doesn’t matter... so I bought the hobbymate pro duo for the car and that charger KICKED THE 💩 out of the venom by 30 minutes sometimes
GREAT VIDEO!!! thanks for the info I have a Venom Pro Quad charger that I have been using for somewhere around 8 years it is a REALLY good charger and never overheats or has any failures. But I noticed that when charging my 6000 mAh 6s Max Amps batteries the last 0.2v -0.5v REALLY CRAWLS and it is because it has Low Current Drain Balancing, only 300 mAh per cell. thanks to you I know what is going on and what to look out for, not that I am gonna toss my Beloved Quad Pro anytime soon, It has REALLY served me well, I can Charge and discharge all the packs I want with NO problems. Unlike the Traxxas Branded ones I Started out with had 3 of them Die on me for DARING to charge TWO Traxxas packs back to back at the SLOW recommended settings, RIP Traxxas NEVER buying those AGAIN
Honestly, what bothers me most about my chargers is noise and cooling power. My ISDT chargers are way too loud when the fan kicks in. And the discharge current could be way higher if the charger just had a bigger heatsink. So, if any charger company wants to make a charger with a "PC grade" heatsink and a big and slow spinning 120mm fan I will buy it! :D
Great Info, one my favorites & the next charger I'll buy is the junsi i charger 6S/ 1100W / 40A w/ 2 amp balance current & fits in the palm of your hand all that for under $119 dollars, who beats that..
I look for chargers with 100 watts per Chanel Dc. They trick you not telling you the 100 watt 50 amps is Ac Dc, now they give highest specs. Once you go through dc, it’s half the specs. I’m still searching for a charger with Dc spec only.
Hello Joshua. I have recently purchased a FMS Smasher v2 RC car 1/24 scale for my grandson. I have very little knowledge of electronics and found your video very informative. The car comes with a usb adapter which hooks up to the 2s battery for charging. Since this is the only lipo battery I have can you recommend a lipo charger that is under $50 with a decent balance current? Also, would I need an adapter to be able to charge it? Thank you.
As I heard, there are some chargers that are capable of charging a battery using only the balance leads. Simple models like IMAX B3 Pro use only balance leads for charging. I think the main reason why we usually use discharge leads to charge a battery is weight. Balance leads are tiny and not capable of passing much current and making them thicker will make battery heavier.
As always no one comes close to you educationally speaking, always gets me thinking. So with what you just covered can the external balance “sipping” rate be used to increase the last bit of charging or is it a nominal time to be saved? So have your old go to chargers changed to the HOTA?
I have older turnigy accucell 6 charger. I’m assuming it doesn’t have the ability to determine if the battery is bad or old . Does this charger you review have a way to determine if the battery is worn out and due for retirement or disposal?
Suppose you have a 2 channel charger with a poor balance current. If you prebalance with something like a ISDT BG-8s will you get shorter charge cycles. My thought is if you have say 4 packs you can be balancing one while 2 others charge. It would be great to see a test as if someone had a poor performing charger and pre balancing works it might be a cheap way to work around the issue and not toss a working charger.
Actually this video is somehow misleading. All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V. So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery. And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
Do chargers really work like this? I see no reason the charger needs to wait for the highest-voltage cell to reach 4.2v before it starts bypassing ("sipping") some current from that cell. I would have expected the charger to be bypassing some current from the highest voltage cell throughout the charging process, thus allowing all cells to be balanced well before any reach 4.2v.
JB you quoted the cause of longer time to charge as the charging balance current should it not be the discharging current balance and capability as the high cell is being in effect discharged. Is it not also true that the drop in current at the end of charging is due to the starting constant current part of the charging cycle changing to constant voltage variable current towards the end of the cycle. Is this not needed to ensure the cell is fully saturated. So the slowdown at the end is required to fully charge the battery as well as allowing balancing to take place. I understand what you are trying to explain but think you are oversimplifying a more complex process. Thank for you imformative videos always good and food for thought. Cheers.
The slowdown at the end is also because of the switch to CC, but balancing can significantly extend the charge time especially if you're using large cells.
@@JoshuaBardwell surely it's the ( constant voltage) CV part of the cycle towards the end of the charge not the CC ( constant current ) which is at the start of the charging process? Thank for your insight.
i've had a thunderpower balancer for years, this used to be the only charge/balance option when changing (limited to 0.3amps if i recall). It's very handy for balancing packs when not changing as well.
I always go for an ISDT with 1.5A balance current; I think you could have put it better: when one of the cells reaches 4.2V, the lipo pack charge current will be limited by the max balance current and not the current that you've set for charging, the charger will not start to slowly discharge that full cell, it will just keep it at 4.2v until the other cells are full, then slowly ramp down the charge current
Actually this is not the case. All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V. So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery. And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
@@mydayq not true, a low balance current will limit you most of the time, if I'm charging a big 4S pack at 10A and it's out of balance, when one of the cells reaches 4.2v the charge current will drop to max balance current even if the other cells are at like 3.9v and it then charges really slow if the the balance current is only 200mA, the current on the full cells will slowly drop as it should until it's full but the pack charge current will only be the balance curent from then on
Seeing as this video was made three years ago I'm wondering if this is still a parameter that is lacking on many chargers that we need to be aware of. What about smart batteries like Spectrum g2, Traxxas (not truly smart), DJI, and other batteries that have logic on board? Would you kindly share your opinion on a quality charger, recommendation.... Affiliate link welcomed and encouraged. Thank you. (Also the charger that you mentioned that has a 1600 milliamp balance current, is that 800 Max for each output since it's a dual charger?). What is the fastest / most powerful balance current device that you've ever seen? Lastly. I much prefer charging through the balance Port only with a very basic slow charger.. nothing to think about, no buttons, nothing to program, just plug it in and leave it for a day or two -- I'm not in a hurry most of the time. There's nothing wrong with this practice, correct?
Hello, I found this video really helpful, I just have one question and that is how do I know a healthy amount of watts to be putting into my Lipo battery?
Is this the same reason why Teslas and other electric vehicles charge the last 10-20% much more slowly than the first 80-90%? I’ve heard the analogy that charging is like “cars filling up a parking lot” and how “when the lot is empty it’s really easy to find a spot, but once the lot is full it takes the car (electron) longer to find a parking spot.” But I wonder if the real reason is that the EV’s charging system is having to balance across cells, and the balance current is similarly reduced relative to the input current?
I will look at watch the other links about chargers. Maybe I can find my answer: why I'd my 1100 50c 4s battery keep discharging when I plug it into the blue charger for the Novice IV rtf kit. Fix or trash?
What about balancing during the charge cycle not just preventing cell overcharge at the end. Lets say 1 cell is 3.5 and another is 3.8 (exaggerated scenario). Does the balancing only kick in once the 2nd cell reaches 4.2 to prevent overcharge or do they try to balance throughout the entire charge cycle. Obviously it's good to prevent overcharge but it's also good to not have unbalanced cells at any point since they're discharging into each other. Would that mean plugging in an unbalanced pack would have to discharge the 3.8 cell down to 3.5 to match the rest until it starts pumping? And does it balance during the charge even if no cells are overcharged? Also does this all safely work with parallel charging boards? How would the charger read and balance cell voltages among multiple battery's
good stuff Could you do a multi part for RC beginners on everything they need. for example, these batteries, well there like 20 cables , No idea which cable connectors need to be purchased. bought a Horus but the you tube vids on converting to ethos are a bit scary. I believe you said once the transmitter could turn into a 300$ decoration! which receivers for which types of planes, gliders etc There should be a place to educate without having to hunt everything down in forums... thanks for all the information you show. U R the best...
I always thought the current is pushed through the main battery lead rather than the balance leads because the balance leads won't handle as many amps without overheating? Whereas the balance leads can easily draw off small amounts of voltage to stop over charging
Parallel charging should equal out the individual cells due to statistics but also because the cells are literally charged parallel, thus equalizing while the charging process is running. So the chance that you have a big Delta in voltage when the first cell(s) hit 4.2V should be lower, right?
Parallel charging does not equalize the series cells with each other. It equalizes the parallel cells. So if you plug in four 4S packs, cell 1 of all four packs is going to be the same voltage, but cells 1 2 3 4 will not.
@@JoshuaBardwell Thanks for rephrasing it better, that's what I was trying to say, but I'm not the big fpv KIA:) Also I didn't know (before), it was just a follow up thought.
MaH Discharge and Recharging question: Battery in use: Xilo 1300 100c 4s Is it normal to balance charge up to 950 MaH but only consistently use less than 400 MaH on 6-minute flights? I’m thinking my charger (Venom Pro3) may be going bad or these Xilos are complete trash? Is it normal to charge that much more than what I'm actually using??
@@JoshuaBardwell ahh, thank you for clarifying. I’ve been keeping a voltage/amp meter spreadsheet to try and figure this out. No wonder I was feeling stuck. Thanks!
Why they don’t have chargers that just charge up balanced is you’d have to have thicker balance leads and connectors which as they are now top out at 3 amps. Plus the circuit for controlling as mentioned would be like having that many charging circuits. although they could each be lower current.
Get some active balancers, if yours is not enough fast. Another thing for charger to do is to balance cells while charging. It doesn't have to be at the end of charge cycle. That's what my toolkit rc m8 does with it's poor balancing current. It's enough for small lipos but not nearly enough for some bigger ones (more than 20ah).
Great info never knew this. I wonder if it’s really going to save that much time/minutes going from a 300mah rated balance charge to a 1.5A in the overall charging of a 4s 6000mah pack? Do I run out an buy a new charger now?
@JoshuaBardwell fantastic video, but I have a question on how to read the specs. ISDT K2 AIR DUO Balance current: 1.5A/Cell Max vs HOTA D6 PRO 1600mA x 2. Which is better? If I understand well, charging e.g. a 4s battery with 1 cell already at 4.2V, the ISDT would discharge the remaining cells at 1.5A each, while the HOTA at 1.6A/3=0.53A per cell. Is the ISDT is so much better than the HOTA??
Hm.. why does the discharing process not begin at the very start? At the very start, already cells are unbalanced - if you start there with balancing and just try to balance the cells aaaaaall the way through the charge? Only starting balancing at the very end does not make a whole lot of sense in my eyes, because typically you charge with 1C, so your charge will take 1 hour anyway in the ideal case. Enough time to get the cells balanced throughout the process?
No it doesn't, that only happens with an "active balancer". You can get them, they use either capacitors or inductors to take and store energy from the higher-voltage cells, and uses it to charge the lower voltage ones.
I love my charger... it's the D100 V2 from SKYRC... but now I'm really disappointed... you destroyed my love 😃 thank you... 300mA/cell But it's ok... I definitely learned something today 👍
Also balance charge current can degrade over time. I have had both my charges fail that way. HobbykingACDC and ISDT Q6 both put many many packs in and still work but balancing can take days
Hey JB. Can you speak to the safety of leaving unbalanced batteries on a parallel board for a few minutes to allow them to balance before changing? Is it safe to plug in a 4s at 16.0 and one at 15.4 and only start the cycle when they both get to 15.7 (for example). Thanks.
I'm Sluuurp sipping all your videos in order to buy the best charger / discharger / cables in order to charger my batteries both at home and on the field !!! :3 with a 18v cars battery I have at home heheh
Wow thats mad so i have been thinking that it charges through the balance port..never looked into it so thats just what i thought! Crazy 10 years on 👍😉
Helo sir i from Indonesia I dont now how to count Watt into Amp I have adaptor input 100watt My charger 200wat 15amp My lipo 4s 9000mah If i charger my lipo how much Amp can i use to the best performance if my input only 100watt? Thanks you sir 🙏
1) Watched video
2) Downloaded manual for my charger
3) Saw balance current rated at 200mA
4) Slammed face on desk
5) Bandaged face
6) Started shopping for new charger...
Thanks, JB! I didn't even know I needed to learn something today...
Jacob, i have 500mA discharge i am wondering if its possible to replace the resistors and improve the discharge ratio
@@lnteI I doubt that. You'd have to change the software as well. Also, mine's only 500mA balance current per cell as well, but it charges my battery quite quickly. Probably because I have a pretty good battery that isn't really out of balance. All of this balance current only matters if you actually have batteries that have differing internal resistances - either due to age or simply the quality of the battery itself.
@@Vousie Most likely firmware is just checking the voltage on each cell and stops charge /activates discharge while one cell is full, i don't think it checks anything else except the actual voltage on each cell.
Once voltage drops to the required level, discharge stops and charging activates.
If this is as simple as that then changing the resistors / fan would totally work, I may sacrifice my charger for this project
@@lnteI Well, let us know if you do try it. 🙂
@@lnteI be a hero and try it...im in the same situation as you
You can tell how truly professional he is when he let out "suck it off" and didn't crack a smile
I did 👌🤣
04:52 I certainly saw a smile XD
Hahaha
I've been in the RC hobby for 20+ years and EVERY SINGLE time I watch one of your videos I learn something new - keep up the fantastic work!
Thanks 👍
This has made me rethink all of the cheaper chargers I have and answers a lot of the "why is this taking so long" questions
The straw analogy makes so much sense now, and the sucking sound just makes it so much easier to understand exactly how the stored energy leaves the battery
4:52 The memes are gonna be strong with this one
🤣
🤣
Am I the only one clicking the 4:52 spot on replay?
@@MatthewTaylor3 5:03 hand and mouth gestures and says; “just sucks it off”. Hahaha I mean he had to know he was dropping some meme worthy content!
5:03 you can't fight muscle memory 🤣
Note: some manufacturers and retailers (like ProgressiveRC) use the term "Current Drain (Balancing)" to list what you refer to as 'balance charge current' - their terminology is more accurate than yours since the full cell(s) are actually drained when topped off whilst the other cells are being charged. On my 4010Duo, for example, it is 1.2A and 2.4A).
BTW, the reason battery balancing of cells works this way is simply cost and safety. Rather than maintaining 4, 5, 6 or more charge paths (or whatever S rating your charger is), each needing to carry a non-trivial amount of current as well as sense circuitry to monitor voltage, it is easier to just dump energy into a an R-bank per cell.
Hey hey hey JB!!!!
You can't just look at the current.
You MUST look at the POWER you can discharge.
If you have 6cell you can't use the entire 1.5A in your case.
Say your battery have 25V, you can only discharge 0.6A.
15W/25V=0.6A, looking at the charger in this video.
I have chargers with a maximum discharge of 5W, really low current when the voltage is high.
The same goes for charging, maximum watt.
Higher voltage the lower the current, and vice versa.
Thank you for great videos.
Keep up the good work informing the comunity.
Hey this is Joe's wife, nice video. I love the time and work you take into explaining how things work. Especially from your point of view. I'm a big fan. Hugs. Much love
I know literally nothing about batteries and charging but getting into RC racing. This video is awesome thanks my man.
Great video JB.
Just a small clarification,
Most chargers start balancing while charging, they dont wait till the end, before the battery is full, the cells are already balanced so they reach 100% SOC at the same time.
Also, the charger doesn’t “suck” current out of the cells, it just shunts the charge current past the full cell.
If you put an amp meter on cell, you will see that no current flows out of it, if it did, the cell voltage would go down, and it never does, it reaches 4.2 and just sits there.
The cell voltage stays the same because the charger is sucking charge out as fast as is being pushed in. The charger can't "shut current" past the cell. The current is pushed into the pack via the main discharge lead and fills all cells equally. If the charger was capable of "shunting" past a cell, then balancing would be just as fast as the main charge cycle.
@@JoshuaBardwell JB, current can only flow one way in a conductor. U can not have current flowing both ways simultaneously. One cancels the other, and no current flows. I can make a simulation schematic showing what actually happens. If current flows in or out of a cell, the cell voltage will inevitably change. Put an amp meter on a cell, and see it happen.
At the end of the charging cycle, the charge current will exactly match the balancing current of the charger. Test it.
Trust me, at the end of the cycle, when a cell reaches 4.2v, NO current flows through the cell.
It flows through the internal resistor bank, past the full cell. This is called current shunting.
Correct you cannot have current flowing both ways in a conductor. The current goes into the main discharge lead and comes out the balance lead. I have verified this with a clamp meter.
@@JoshuaBardwell right, so if the current flows through the main lead, then out though the balance lead, then it doesn’t flow through the cell, does it now?
@@JoshuaBardwell i am on a phone right now.
When i get back home, i will make a circuit simulation, showing exactly what happens.
But the short of it is: the charger shunts its own charging current through its own resistor bank.
And no current flows through the cell, from the cells “point of view” is like nothing happens, its as if it was completely disconnected from the circuit. I know its a bit tricky, but thats what the charger does. This is exactly why, when the charger is balancing, the charge current equals the balance current. It is the SAME current.
It's not only balance current that matters, but also algorithm. Old IMAX B6 works like Joshua describes. I was pleasantly surprised that ISDT charger starts balancing long before cell is full, therefore final balancing phase at the end takes just seconds.
Regardless of when the balancing occurs, it can only occur as fast as the balance current allows, so it adds to the charge time either way. Possibly it's better to do it in the Constant Current part of the charge vs. the Constant Voltage at the end.
@@JoshuaBardwell But regardless of how high a balance current your charger is capable of, it only matters if you have very unbalanced batteries... Which you may not have if you are using reasonably new & good quallity batteries.
@@JoshuaBardwell If you have charger with 500mA balance current, it could compensate up to 500mAh imbalance without losing any time. Isn't it enough?
icharger 406 Duo FTW! 40 amp discharge per side 70-80amps if you combine both channels also can do regenerative discharging into my 2x120wh deep cycle batteries, don't buy cheap, spend extra and buy 1 time, have had this thing for years and it's freaking the best even has sd-card logging!
Yes, they actually do this "passiv balancing" because it IS simpler and cheaper.
The other thing is "active balancing"
Exactly, Simpler to just connect a resistor to one or more of the cells than to have an extra charger for the cells.
do you know any good charger with active balancing? seems to be a more efficient solution
Like you said, I’m gonna learn something today. Not every day, but today I did! I’m actually in search of a charger that will do 5000 plus mAh 6s packs for my boat and my quad so That’s going to help me in my decision making of the charger tremendously. Thank you sir. 👍👍
Your ability to explain unfamiliar topics in a manner which I can instantly understand - is such a gift. Thanks man.
Actually this video is somehow misleading.
All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V.
So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery.
And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
Holy crap! I actually learned something today. I had no idea it was sipping. I did assume it was pumping.
How did you get so smart? I'm mean...
My entire life people came to me for answers and yet when I watch your videos I feel like a student that doesn't want to leave class.
Freaking amazing!
He isn't as smart as you think, he believes in NASA and if he would watch this he might have a change in heart ua-cam.com/video/itCwbKUy6TM/v-deo.html its NASA's origin story. And its jaw dropping
@@chrisw3493 Yeah.. Sure.. What ever you say.😄👌.
@@chrisw3493 Try not to hurt yourself on such sharp humor.
1. Most chargers probably charge over the discharge leads mostly (and discharge slowly over the small balance leada) because you can transfer much more current over the big wires without overheating the wires.
2. Is the diagram correct/consistent? Should the cells with the lower resistance not also charge up at a higher rate, reversing some of the imbalance?
I wondered this too, but I think because their resistance hasn't changed between being discharged and charged, then the input difference would be the same as the discharge difference, and it *should* reach full at roughly the same time as the others if all cells charge and discharge at the exact same current. I'm only speculating though.
I also wondered if the charger will get slower and slower for each cell that is full, or if the charger can pull that rate out of every cell simultaneously. I see that the charger info in the video said 1.5A per cell balance rate, but do they all work like that?
Explained this so well, I have cell imbalance on 3 x DJI TB47S batteries, just need a video from you now to explain how I can bypass the smart charging circuit board on those and start properly balancing my cells. Keep up the great work
Thank you Sir. I purchased this charger yesterday and I am now reassured that It was a good purchase if you are using it too.
Balancing is also charger dependent, some older chargers had their own dc-dc on the balance lead so it could discharge one cell and charge right into another cell with the power rather than wasting it, also allowing charging of single cells while balancing. Most balance chargers merely shunt a resistor across the cell(s) to only discharge the cell. The dc-dc per cell was much faster at balancing as it avoided most discharging of cells when done.
Great video as usual! I only have one charger that charges through the balance plug, and it is only for small 2S batteries. That’s OK because small batteries don’t need much current. If you were to charge a larger battery (or parallel board) through the balance plug, then the current rating of the wires and the JST-XH connector could be a limiting factor. So that’s another factor that may encourage manufacturers to use the main discharge lead for charging.
I’ve got a charger that charges from the balance lead and charges at up to 4 amps. It’s nice not needing a lot of charge adapters but I think it’s more efficient at charging.
@@habenero_fpv that is surprising. The JST-XH connector is only rated for 3A continuous. datasheet.octopart.com/XHP-4-JST-datasheet-8325564.pdf
We often exceed the recommended current on connectors in flight, but that is for a short duration with extra air cooling. I would expect a charger to be more conservative on the ratings.
@@MrShutterBug it’s not continuous, and my balance plugs seem to be holding on. Checking the specs and it charges up to 4 amps and balances at 1.5 amps. It does all this thru the balance port.
@@habenero_fpv what type of charger is that?
please give the full specification of the discharge resistor that you showed. I tried setting up my own rig like this but the resistors heat up too quickly. I have been discussing this in the ELRS Community discord in the ganeral-quad-help channel . I have reached the point where I don't know what move to make next. cheers
There are really two issues in balancing charging. One is variations in internal cell resistance (as you mention). But balance current doesn't help with this. The only way to handle mismatches in cell resistance is to slow down the entire stack charging rate to prevent exceeding max voltage on the most resistive cell. For this, the role of the balance leads are to measure individual cell voltages. The second issue is differences in cell capacity. Even with perfect manufacturing, cells lose charge capacity at different rates as the stack ages. This is where the discharge current comes in. The charger must allow some of the main stack current (which goes through all the cells) to partially bypass cells with lower capacity. The big slow down you have at the end of the cycle includes both of these effects.
Every time he opens his fridge at the end, I'm surprised when I don't see a white claw hanging out in the door 😄
That is very interesting I have never heard this mentioned before.
I now understand why the Hitec X4 (300 mah balancing) took forever.
I quite flying three years ago, still enjoy the videos.
It's because the wire gauge of the balance leads are not large enough to charge at full rate through the balance lead.
Thanks JB, when hunting for a great charger, this became my main criteria. I now have 2 of ye old faithful ISDT T8's on my desk :)
Only thing to watch is whether the balance current quoted in the specs. is total, or per cell. "1600 mA" (for example) sounds good, but on a 6S charger that might mean 267 mA per cell (1600 / 6). Another charger might quote "250 mA" for the balance current, which sounds pretty puny but if that's per cell then both chargers could basically be the same.
are you talking about hota d6? I have the same question.. 1600 total or 1600 per cell?
@@guarf for that charger (I have one myself) it's up to 1600 mA for each of the two outlets ... but it's unclear whether this is a fixed 267 mA per cell, or whether you'd get (say) 800 mA per cell if you were charging 2S, 533 mA per cell with 3S, etc.
Less charging voltage = more current drawn and a hotter charger. The inverse is also true. More voltage will shove less current into your batteries faster and cooler, but don't take that as any information to act on. My B6 charger was an illustration of that basic electrical premise as I wondered why I had to replace a melted barrel connector. 16 volts instead of 12 solved that issue.
Not an FPV person - fixed wing. found this video very informative thank you.
Just bought the K2 as getting into larger 6s batteries
On the subject of balance charging, as an experiment I made a very simple 2S charger that runs off USB 5v and fully balances the cells, because it charges them individually, at the same time.
How?
Miniature 5v DC-DC isolation transformers is the secret ingredient - you put 5v in to two of the pins, and you get 5v out of the other pins, but the output is completely isolated from the input.
Basically: 5v goes into a LTC4056 1S lipo charging board which is then connected to the first two pins of the 2S lipo's balance plug.
But you can't simply connect that same 5v source to another LTC4056 and connect it to pins 2+3 of the lipo's balance plug because you'd be shorting out the first charger board and the first two pins of the lipo.
So you drive the 2nd LTC4056 from a 5v DC-DC isolation transformer, preventing any shorting.
Slow? Yes it can be, but you do end up with a properly charged 2S pack. If you add another isolation transformer & LTC4056 you can charge a 3S that way too. But I'm not recommending anyone do this, I just did it out of curiosity.
I already had idea about balancing current as main culprit why my old trusty SkyRC D100 charger charge batteries to brim quite fast, but balancing continue for another 20-40 minutes. Especially for used 4-6 cell batteries at end of season. Turned out that thing have only 300 mA balancing current. Already decided to buy proper charger with built-in AC power supply.
Update: Purchased HOTA D6 Pro a week later. With 1.6A balance current charging now ends much faster.
The graphics and sound effects are making me uncomfortable.
Another thing to consider is that some better chargers will discharge the higher cells as soon as they begin charging rather than waiting til the end, which will make it much more effective, but a higher balance current is still beneficial.
Also, the reason the battery seems to slow at the end is due to the CV portion of the CC/CV cycle, so even though the voltage shows ''charged', it is being pushed to that point and held there, and will drop down if the charge is stopped at that point. This is also why the current drops at the end, as during the CV phase the charger maintains the set voltage and just supplies whatever current that causes the battery to pull.
It legitimately took my charger 27 hours to balance a 4s 6000mah li-ion battery that I forgot to balance the cells before assembling it. Balance current definitely matters!
So is it safe to say that a charger that can do 200watts at 25amps with a balance current of 400ma is slower than a charger that does 150watts at 16amps with a 1.2amp balance current.???
Would you be able to do a video of testing all the different capacities of a 4 S and 6S batteries and graphing the respective flight times. E.g for 4S: 1200MaH = 4mins, 1300MaH = 4.5 mins, etc so that we can see when the weight is no longer beneficial on a standard 5” quad!
Josh as always great video, I have searched youtube with no success maybe you can help me, and a thousand other retired seniors that are not so computer savy! I have been flying fixed wing for 40 yrs and a couple yrs ago i got a tiny whoop and have progressed to doing a small amount of tuning with some success because of you and your how to video's, recently I discovered the DJI mini 2, I want so bad to buy one but I know absolutely nothing about recording anything to a micro disk much less playing it on my computer (chromebook) and it would be even better if I could share a video. Believe me when I say there are a lot of us in need of someone to take us by the hand and lead the way, of course I think this would make a great series of video's for people like me who want to but just don't have the know how. Thank You Josh keep up the good work.
VENOM!!!! GD VENOM!!! I have that $270 4 bay big boy! First and biggest one I could find that had the best specs that I could find...... come to find out it TAKES FOOOOOREEEEEEVEEEEEERRRRRR TO CHARGE any ANY lipo new old doesn’t matter... so I bought the hobbymate pro duo for the car and that charger KICKED THE 💩 out of the venom by 30 minutes sometimes
@Joshua Bardwell What charger/multi charger/charging cards would you buy in 2022-2023? Ty for your help
GREAT VIDEO!!! thanks for the info I have a Venom Pro Quad charger that I have been using for somewhere around 8 years it is a REALLY good charger and never overheats or has any failures. But I noticed that when charging my 6000 mAh 6s Max Amps batteries the last 0.2v -0.5v REALLY CRAWLS and it is because it has Low Current Drain Balancing, only 300 mAh per cell. thanks to you I know what is going on and what to look out for, not that I am gonna toss my Beloved Quad Pro anytime soon, It has REALLY served me well, I can Charge and discharge all the packs I want with NO problems. Unlike the Traxxas Branded ones I Started out with had 3 of them Die on me for DARING to charge TWO Traxxas packs back to back at the SLOW recommended settings, RIP Traxxas NEVER buying those AGAIN
Honestly, what bothers me most about my chargers is noise and cooling power. My ISDT chargers are way too loud when the fan kicks in. And the discharge current could be way higher if the charger just had a bigger heatsink.
So, if any charger company wants to make a charger with a "PC grade" heatsink and a big and slow spinning 120mm fan I will buy it! :D
Great Info, one my favorites & the next charger I'll buy is the junsi i charger 6S/ 1100W / 40A w/ 2 amp balance current & fits in the palm of your hand all that for under $119 dollars, who beats that..
500 mA sounds scary, i prefer half an amp. you the man joshua.
I look for chargers with 100 watts per Chanel Dc. They trick you not telling you the 100 watt 50 amps is Ac Dc, now they give highest specs. Once you go through dc, it’s half the specs. I’m still searching for a charger with Dc spec only.
Hello Joshua. I have recently purchased a FMS Smasher v2 RC car 1/24 scale for my grandson. I have very little knowledge of electronics and found your video very informative. The car comes with a usb adapter which hooks up to the 2s battery for charging. Since this is the only lipo battery I have can you recommend a lipo charger that is under $50 with a decent balance current? Also, would I need an adapter to be able to charge it? Thank you.
As I heard, there are some chargers that are capable of charging a battery using only the balance leads. Simple models like IMAX B3 Pro use only balance leads for charging. I think the main reason why we usually use discharge leads to charge a battery is weight. Balance leads are tiny and not capable of passing much current and making them thicker will make battery heavier.
Got myself HOTA D6+ 300W, works perfectly
I noticed this when I bought a D6 Pro vs ISDT 608AC. Much faster charging/discharging, but I still keep the 608 in my bag since its so portable!
As always no one comes close to you educationally speaking, always gets me thinking. So with what you just covered can the external balance “sipping” rate be used to increase the last bit of charging or is it a nominal time to be saved? So have your old go to chargers changed to the HOTA?
I have older turnigy accucell 6 charger. I’m assuming it doesn’t have the ability to determine if the battery is bad or old . Does this charger you review have a way to determine if the battery is worn out and due for retirement or disposal?
You would want internal resistance measuring. I'd at least check to see if it can measure IR.
Suppose you have a 2 channel charger with a poor balance current. If you prebalance with something like a ISDT BG-8s will you get shorter charge cycles. My thought is if you have say 4 packs you can be balancing one while 2 others charge. It would be great to see a test as if someone had a poor performing charger and pre balancing works it might be a cheap way to work around the issue and not toss a working charger.
Actually this video is somehow misleading.
All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V.
So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery.
And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
Do chargers really work like this? I see no reason the charger needs to wait for the highest-voltage cell to reach 4.2v before it starts bypassing ("sipping") some current from that cell. I would have expected the charger to be bypassing some current from the highest voltage cell throughout the charging process, thus allowing all cells to be balanced well before any reach 4.2v.
Thanks for the congratulations Joshua Bardwell, this is the best explanation of balance charging I've heard in a while
JB you quoted the cause of longer time to charge as the charging balance current should it not be the discharging current balance and capability as the high cell is being in effect discharged. Is it not also true that the drop in current at the end of charging is due to the starting constant current part of the charging cycle changing to constant voltage variable current towards the end of the cycle. Is this not needed to ensure the cell is fully saturated. So the slowdown at the end is required to fully charge the battery as well as allowing balancing to take place. I understand what you are trying to explain but think you are oversimplifying a more complex process. Thank for you imformative videos always good and food for thought. Cheers.
The slowdown at the end is also because of the switch to CC, but balancing can significantly extend the charge time especially if you're using large cells.
@@JoshuaBardwell surely it's the ( constant voltage) CV part of the cycle towards the end of the charge not the CC ( constant current ) which is at the start of the charging process? Thank for your insight.
Sorry -- I mis-typed CC instead of CV.
i've had a thunderpower balancer for years, this used to be the only charge/balance option when changing (limited to 0.3amps if i recall). It's very handy for balancing packs when not changing as well.
I always go for an ISDT with 1.5A balance current; I think you could have put it better: when one of the cells reaches 4.2V, the lipo pack charge current will be limited by the max balance current and not the current that you've set for charging, the charger will not start to slowly discharge that full cell, it will just keep it at 4.2v until the other cells are full, then slowly ramp down the charge current
Actually this is not the case.
All lithium batteries are being charged with CC/CV algorithm. Firstly its CC - Constant current. So if you have battery like 1500mah and you charge it with 1C which is 1.5A, charger will use all of 1.5A untill one of the cell reach 4.2V. Then after watching this video you might think that charging of that cell should be stopped so if you have 200ma balance current, other cell instead of charging with 1500mA (or 1.5A) will be charged at 200mA and it will take ages. But this is not the case. When 4.2V is reached, a charger ctarts CV phase - Constant Voltage. So charging of thar 1st cell will continue with slowly declining current. 1.45A, 1.4A, 1.35A and so on, while Voltage will be Constant at 4.2V.
So when 1 of the cell will hit 4.2V with inital current of 1.5A, other cells still will be charging with 1.5A untill current on the first cell will drop as low as 1.29A (if you have 200mA balance charging). And even after that current will decline very slowly and unless your battery not so messy and big, even 200mA balance current will not be a limiting factor for standard fpv battery.
And knowing this you cold monitor charging and find it out for yourself. CV is usually ends when current drops al low as 0.1-0.15A, so every charging process slows down at the end, even if you charre 1 cell battery (1s).
@@mydayq not true, a low balance current will limit you most of the time, if I'm charging a big 4S pack at 10A and it's out of balance, when one of the cells reaches 4.2v the charge current will drop to max balance current even if the other cells are at like 3.9v and it then charges really slow if the the balance current is only 200mA, the current on the full cells will slowly drop as it should until it's full but the pack charge current will only be the balance curent from then on
really good tip, I never looked at that parameter and thinking of getting a new charger so good to know
Seeing as this video was made three years ago I'm wondering if this is still a parameter that is lacking on many chargers that we need to be aware of.
What about smart batteries like Spectrum g2, Traxxas (not truly smart), DJI, and other batteries that have logic on board?
Would you kindly share your opinion on a quality charger, recommendation.... Affiliate link welcomed and encouraged. Thank you.
(Also the charger that you mentioned that has a 1600 milliamp balance current, is that 800 Max for each output since it's a dual charger?).
What is the fastest / most powerful balance current device that you've ever seen?
Lastly. I much prefer charging through the balance Port only with a very basic slow charger.. nothing to think about, no buttons, nothing to program, just plug it in and leave it for a day or two -- I'm not in a hurry most of the time. There's nothing wrong with this practice, correct?
Hello, I found this video really helpful, I just have one question and that is how do I know a healthy amount of watts to be putting into my Lipo battery?
Is this the same reason why Teslas and other electric vehicles charge the last 10-20% much more slowly than the first 80-90%? I’ve heard the analogy that charging is like “cars filling up a parking lot” and how “when the lot is empty it’s really easy to find a spot, but once the lot is full it takes the car (electron) longer to find a parking spot.” But I wonder if the real reason is that the EV’s charging system is having to balance across cells, and the balance current is similarly reduced relative to the input current?
I will look at watch the other links about chargers. Maybe I can find my answer: why I'd my 1100 50c 4s battery keep discharging when I plug it into the blue charger for the Novice IV rtf kit. Fix or trash?
I just watched your vids and bought the Hobbymate I see sitting around your shop. Can't really go wrong with that logic.
What about balancing during the charge cycle not just preventing cell overcharge at the end. Lets say 1 cell is 3.5 and another is 3.8 (exaggerated scenario). Does the balancing only kick in once the 2nd cell reaches 4.2 to prevent overcharge or do they try to balance throughout the entire charge cycle. Obviously it's good to prevent overcharge but it's also good to not have unbalanced cells at any point since they're discharging into each other. Would that mean plugging in an unbalanced pack would have to discharge the 3.8 cell down to 3.5 to match the rest until it starts pumping? And does it balance during the charge even if no cells are overcharged? Also does this all safely work with parallel charging boards? How would the charger read and balance cell voltages among multiple battery's
Should i buy HOTA D6 pro or ISDT K2?
Can that 1,5A/cell (K2) be true?
D6 pro says 1,6A/ port.
good stuff
Could you do a multi part for RC beginners on everything they need. for example, these batteries, well there like 20 cables , No idea which cable connectors need to be purchased. bought a Horus but the you tube vids on converting to ethos are a bit scary. I believe you said once the transmitter could turn into a 300$ decoration!
which receivers for which types of planes, gliders etc
There should be a place to educate without having to hunt everything down in forums...
thanks for all the information you show. U R the best...
So 1.5A per cell is good or 1.5A total? Mine has 0.5 per cell
I always thought the current is pushed through the main battery lead rather than the balance leads because the balance leads won't handle as many amps without overheating? Whereas the balance leads can easily draw off small amounts of voltage to stop over charging
Correct.
800mah balance current too slow? or its ok for a 1400mah 6s lipo?
Cellpro chargers charge balance instead of discharge balance.
Is ISDT do the same ?
Hota d6 dual is a great charger.I got rid of my high end icharger after getting one because it was balancing and charging so much more efficiently
So which would be the best charger or one that works really good and is worth getting? As I need a new one ASAP? cheers
so what happens when you just use the normal (not balance) charge mode? does it just stop when one cell reaches 4.2?
Parallel charging should equal out the individual cells due to statistics but also because the cells are literally charged parallel, thus equalizing while the charging process is running. So the chance that you have a big Delta in voltage when the first cell(s) hit 4.2V should be lower, right?
Parallel charging does not equalize the series cells with each other. It equalizes the parallel cells. So if you plug in four 4S packs, cell 1 of all four packs is going to be the same voltage, but cells 1 2 3 4 will not.
Of course parallel cells means cell 1 (2, 3, ...) of each pack are connected parallel, not the cells within one pack (they are of course S).
@@JoshuaBardwell Thanks for rephrasing it better, that's what I was trying to say, but I'm not the big fpv KIA:) Also I didn't know (before), it was just a follow up thought.
MaH Discharge and Recharging question:
Battery in use: Xilo 1300 100c 4s
Is it normal to balance charge up to 950 MaH but only consistently use less than 400 MaH on 6-minute flights? I’m thinking my charger (Venom Pro3) may be going bad or these Xilos are complete trash? Is it normal to charge that much more than what I'm actually using??
It may mean your current sensor is mis-calibrated.
@@JoshuaBardwell Get a new charger. Got it :)
No.... in the FC the current is reading wrong. The charger is almost certainly reading right.
@@JoshuaBardwell ahh, thank you for clarifying. I’ve been keeping a voltage/amp meter spreadsheet to try and figure this out. No wonder I was feeling stuck. Thanks!
Why they don’t have chargers that just charge up balanced is you’d have to have thicker balance leads and connectors which as they are now top out at 3 amps.
Plus the circuit for controlling as mentioned would be like having that many charging circuits.
although they could each be lower current.
I think it's time for a new intro video. What do you think JB?
Get some active balancers, if yours is not enough fast. Another thing for charger to do is to balance cells while charging. It doesn't have to be at the end of charge cycle. That's what my toolkit rc m8 does with it's poor balancing current. It's enough for small lipos but not nearly enough for some bigger ones (more than 20ah).
Great info never knew this. I wonder if it’s really going to save that much time/minutes going from a 300mah rated balance charge to a 1.5A in the overall charging of a 4s 6000mah pack? Do I run out an buy a new charger now?
@JoshuaBardwell fantastic video, but I have a question on how to read the specs. ISDT K2 AIR DUO Balance current: 1.5A/Cell Max vs HOTA D6 PRO 1600mA x 2. Which is better? If I understand well, charging e.g. a 4s battery with 1 cell already at 4.2V, the ISDT would discharge the remaining cells at 1.5A each, while the HOTA at 1.6A/3=0.53A per cell. Is the ISDT is so much better than the HOTA??
I think those two specs are almost the same just the way, they write them is confusing.
Hm.. why does the discharing process not begin at the very start? At the very start, already cells are unbalanced - if you start there with balancing and just try to balance the cells aaaaaall the way through the charge? Only starting balancing at the very end does not make a whole lot of sense in my eyes, because typically you charge with 1C, so your charge will take 1 hour anyway in the ideal case. Enough time to get the cells balanced throughout the process?
Either way, you have to slow down to let the lower cells catch up.
isdt t8 - 2.2a balance current.. im happy with that!
Wow, was expecting the ISDT 608AC to be low due to its size, but 1.5A balance current.
I did learn something. I thought it was diverting the “sucked off” portion back to the cells with lesser voltage.
No it doesn't, that only happens with an "active balancer". You can get them, they use either capacitors or inductors to take and store energy from the higher-voltage cells, and uses it to charge the lower voltage ones.
What do you think for b6v3 charger, seems fast to me
I love my charger... it's the D100 V2 from SKYRC... but now I'm really disappointed... you destroyed my love 😃 thank you... 300mA/cell
But it's ok... I definitely learned something today 👍
I have ISDT 608AC. When I look at it when charging, it looks like it first balances the cells and then charges the whole battery as one. Seems good
new isdt k2 says 1.5a per cell. Cant believe that's true. Maybe they mean per battery?
Wish I knew about this sooner, I’ve been charging lipos since 2014 and would have bought different chargers based on this knowledge. 🤦🏽♂️😂
Where to get your shirt?
I started charging at 2.5a was doing 1 the whole time, save so much time
Also balance charge current can degrade over time. I have had both my charges fail that way. HobbykingACDC and ISDT Q6 both put many many packs in and still work but balancing can take days
Hey JB. Can you speak to the safety of leaving unbalanced batteries on a parallel board for a few minutes to allow them to balance before changing? Is it safe to plug in a 4s at 16.0 and one at 15.4 and only start the cycle when they both get to 15.7 (for example). Thanks.
ua-cam.com/video/yTEGhKBv09M/v-deo.html&ab_channel=JoshuaBardwell
Think the general rule of thumb is 0.1 volt per cell difference max, any more than that may lead to bad things.
I'm Sluuurp sipping all your videos in order to buy the best charger / discharger / cables in order to charger my batteries both at home and on the field !!! :3 with a 18v cars battery I have at home heheh
Wow thats mad so i have been thinking that it charges through the balance port..never looked into it so thats just what i thought!
Crazy 10 years on 👍😉
My isdt q6 nano has only 500mA It's so slow. So i ordered rctoolkit m9 it has 1.5Amps balance current.
Hmm, so my SkyRC Q200 is actually incredibly bad?
Specs say "Current drain for balancing port: Max 200mA/Cell"
T200 only 500mA
Piss poor especially for the price they ask
Hota are much better value
Helo sir i from Indonesia
I dont now how to count Watt into Amp
I have adaptor input 100watt
My charger 200wat 15amp
My lipo 4s 9000mah
If i charger my lipo how much Amp can i use to the best performance if my input only 100watt?
Thanks you sir 🙏