I think a parallel charging board would be better than not balance charging. I charge my lipos like this (not my photo) and I charged all my batteries one time in 15min because i was in a hurry.
15 minutes would be a dream, thankfully I have 8 hours during the day I can charge. Is it really a huge deal if one cell is lower than the others? I’ve yet to drain any single cell lower than 3.8 volts since I use the board almost exclusively for my 4 mile commute to work and charge it during the day.
I guess it might not be the biggest deal if the voltage difference is not more than .4 volts. Ideally you want them at same voltage for longevity. I’m more worried about overcharging never go above 4.2v per cell
it takes so long to balance charge because your cells are so badly of of balance. you can speed it up by setting your charger to 2S and then charging the 2 cells that are only reading 4.16V
oh shoot i didn’t realize this was possible! I’ll try it out real quick!
meh, no luck. my charger gave me an error saying I had the wrong number of cells selected. Good news is that even with the cells out of balance, “fast” .75C charging has never taken the cells over 4.2, and they’ve never been drained past 3.8 since my commute is so short. I’ll just keep balance charging them every day after the fast charge cuts off until they’re back in order, 2 of my 3 batteries are right where they should be with just a .01v variance. Thanks for all of the tips and pointers, lesson learned is to balance charge as much as possible.
I agree, and also I feel like I’m sacrificing a bit of range with 2 cells being .05 and .04 v off, thats almost an entire volt, which is pretty significant. Thankfully my chargers fast charge setting doesn’t take any individual cells over 4.2 before it cuts off, leaving the others at 4.16 and 4.15. I plan to fast charge till it cuts off, then balance charge the other two up as close to 4.2 as I can before I need to ride again. Thanks for all of your pointers!
you need to obviously isolate the 2 cells. you cant use the same balance lead. you need to custom make a 2S lead to do it. other wise the charger just wont let you
that wasn’t so obvious, and sounds like a bunch of work for what can be fixed while I work tomorrow with an 8 hour slow balance charge to get things evened out. lesson is learned though.
when you use the balance charge function on your charger it does a funny little dance with a series of resistors across each cell. when a cell reaches 4.20V it stop charging all cells puts a resistor across that cell and waits for it to drain down to 4.19V and then starts charging all cells again. the reason it takes forever to charge is because it is in fact NOT charging but rather discharging your 4.20V cells ever so slowly, before ever so slowly trying to charge all the other cells only to be stopped again by the high cell. this dance continues, charging and discharging 0.01V up and down for hours at a very low amperage.
the only way to stop this is to individually charge each low cell up to 4.20V (or at least whatever voltage the high cell is at) via the balance connector. setting your charger to 1S or 2S accordingly… you will likely need to custom make a cable for 2S but 1S cables are probably provided with your charger.
My apologies for my previous post which is now withdrawn, it was not very friendly to @lowGuido, I meant no offense. I think I have been a bit spooked by this thread: http://www.electric-skateboard.builders/t/exploding-lipo-batteries-is-no-joke/9634?u=dinodave
I don’t believe most people should try to screw around with what @lowGuido is recommending here however. If you know exactly what you are doing and have full faith in your charger and wiring, by all means, it could sort out your problem. It’s just that there are possibilities things could go wrong if you make a mistake, so please be careful.
by all means be careful with lipos. they can be dangerous. I’d even say more dangerous charging unattended…
here is a good video. watch it and it will explain everything.
1 Like
Hey guys, just wanna say how much I appreciated the input. I spent the morning balancing my cells and now it’s balance charging at .75C, which is basically as fast as the fast charge was going. Balance charging from now on since its not any faster than fast charging
1 Like
You should never fast charge Lipos. You should always balance charge Lipos. Balance charging doesn’t take that long. I could fully balance charge a 6s 5000mah Lipo pack in 1 hour or less charging at 5amps. If your pack won’t balance, it may already be damaged from unbalanced fast charging.
I think they arrived a little unbalanced, which is why it was taking hours to balance one battery. After all the advice last night I spent the past 8 hours balancing them, then took a short joy ride. Now they balance at .75C which is perfect! Will definitely be balance charging for now on
1 Like
When ever I buy Lipos I check them first with a Turnigy IR meter. I’ve gotten 2 bad packs from HK right out of the box. Lipos should have no more than 5 miliohms per cell when new.
Having this same problem with one of my 5000mAh 30C LiPo the past few days. Cell 1: 4.16 Cell 2: 4.16 Cell 3: 4.20
I have tried to leave it at Balance Charging for more than an hour yesterday but it stayed at those values.
Today as of this moment I am Discharging it at 1A to about 3.7V per cell and will see if they come together. Then will Balance Charge back up. (BTW I always Balance Charge my LiPos and this was the only LiPo out of my 3 that went off track.
there is 2 types of balancing; top balancing and bottom balancing. you can either discharge all cells to the lowest voltage of charge all cells to the highest voltage. i would suggest to try both in succession to bring them back.
One of my 10s1p packs with integrated BMS is only charging to 40.9 volts, after about 100 cycles. So I’m assuming the cells are out of balance. I had made it a habit of trying to keep the voltage under 40-41 volts most of the time to increase cycle lifetime. But after reading about how balance charging works, it looks like I might have not allowed the BMS to do its work, because it only functions on fully charged cells. So does this mean it’s actually better to always fully charge battery packs to keep them balanced? I hope I can get it balanced again, leaving it plugged in over night didn’t help so far. Does it make a difference if you’re charging with a higher or lower amp charger?