The most over-looked lipo charger spec: Balance Current
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- เผยแพร่เมื่อ 18 เม.ย. 2021
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Balance current might be the most over-looked lipo charger spec. Everybody focuses on watts and amps, but if your charger's balance current is too low, your whole charging process can come grinding to a halt.
My tutorial about how to evaluate battery charger specifications: • Battery charger fundam...
You can tell how truly professional he is when he let out "suck it off" and didn't crack a smile
I did 👌🤣
Complete with sound effects and visual aids.... Wow 😳
🤣
04:52 I certainly saw a smile XD
Hahaha
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
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
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 👍
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 🤣
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).
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
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.
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
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 :)
Holy crap! I actually learned something today. I had no idea it was sipping. I did assume it was pumping.
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.
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.
Not an FPV person - fixed wing. found this video very informative thank you.
Just bought the K2 as getting into larger 6s batteries
really good tip, I never looked at that parameter and thinking of getting a new charger so good to know
This was so useful, thx for answering the question I didn't know I needed to know about
As always, I learnt something today Joshua! Thanks.
This. This is why I love your channel. 👍
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 😄
Am I the only one who loves JBs thumbnail faces? The best! Keep killin it my good man!
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. 👍👍
Well I learned something today! Glad I bought my d6 from your previous videos
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 th-cam.com/video/itCwbKUy6TM/w-d-xo.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.
Always saving here Joshua, tanks!
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.
Much needed video! Thank you for this!
Another great video, you explain things very well
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.
Got myself HOTA D6+ 300W, works perfectly
Good info! I need one of those hi watt res in my life!
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?
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!
Great video. Helps me a lot.
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.
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.
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
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?
ty mr bardwekl i finally understoob the balance process...!
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.
Good info, Thanks!
I love my spectrum smart charger..lol.. great video I needed the knowledge thank you..
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
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!
nice topic thanks for this....
Great explanation!
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!
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!
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
thanks Josh.
Really, REALLY interesting! Thanks a lot, Joshua! 😃
I'm going to be looking for that!
Stay safe there with your family! 🖖😊
do you have a macro for that last sentence
Great video!
Joshua Bardwell, thanks I learned a lot today, now the next question is it possible to replace the resistors to improve the discharge ratio on balance lead? :)
In theory, this easy to do, anyone tried this?
It's because the wire gauge of the balance leads are not large enough to charge at full rate through the balance lead.
@Joshua Bardwell What charger/multi charger/charging cards would you buy in 2022-2023? Ty for your help
I'm so happy I dont have this issue with my ISDT Q8 while charging 6S packs (unless I need to discharge)
Very good explanation.....
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.
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?
I have this strange feeling ELRS will be the topic of your next video.
Cant wait;)
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.
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
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?
amazing! Thanks!
Very interesting. Thanks
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 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?
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..
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
isdt t8 - 2.2a balance current.. im happy with that!
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
Should i buy HOTA D6 pro or ISDT K2?
Can that 1,5A/cell (K2) be true?
D6 pro says 1,6A/ port.
Very cool to know thanks!
Thanks
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
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
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, i really doesn't know that a charger work like you explained
Where to get your shirt?
my team orian duo is rubbish in the balance phase ,,ive orderd a ISDT K4 ,,great video
what about a charger stating (Current drain for balancing:500mA/cell) same??
@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.
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.
Does it start to balance the "Hot Cell" before 4.2 or does it start as soon as it realized one cell is higher?
seems smart to try to balance the charge the entire time.
or maybe if they had external discharge option. that one extra cell powers USB charger...
Plug in a CPU cooler...
What happens with parallel charging?
Is "fast charge" up until one cell hits 4.2 then it goes to whatever the balance discharge rate?
The exact method differs. Some chargers do begin balancing before one cell hits 4.2 if they notice one cell is way higher. Others wait until the end.
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 👍😉
so what happens when you just use the normal (not balance) charge mode? does it just stop when one cell reaches 4.2?
What a great video’
I think the toolkitrc m8 switches between charging and balancing
Great video, stayed for the Refrigerator Scene...I'm beyond help ..🤔😳😯🇬🇧
800mah balance current too slow? or its ok for a 1400mah 6s lipo?
So 1.5A per cell is good or 1.5A total? Mine has 0.5 per cell
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
hi joshua, what about the balance current / cell? your example is 1500mah per port I assume, so should be devided by number of (cells - 1)
my chargers has 500mah balance current per cell. so, 4s pack = 3*500 is also 1500
Regardless, higher balance current rating is better.
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.
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.
th-cam.com/video/yTEGhKBv09M/w-d-xo.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 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.
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.
I really did learn something today. My cheap charger sucks haha