Using a 16s charger on a 14s battery pack. Will the bms protect it?

eikido

10 W
Joined
May 8, 2019
Messages
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If I ever did a mistake and used a 16s charger on a 14s battery pack, what would be the consequences? Would a some what advanced bms protect from charging over 58.8v?

Because using a 16s charger on a 14s battery pack would charge each cell at around 4.8v which is not good at all. I wonder if the bms would protect it.
 
Worst case scenario it burns your bike to the ground along with everything in it's vicinity and possibly hurts or kills someone. Ask some of the members here who have had their homes burn down about their feelings on leaving it up to a BMS to protect you. I suspect they would advise against it.

If you're looking for confirmation that it would be ok to intentionally charge this way, you likely won't find it here. That said if you don't have a 16s pack that you need to charge it may be possible to open the charger and adjust the pots inside to make it work in an appropriate way for your 14s pack.
 
No do not try it the charger will put out more amps than the BMS canvas Spurs and it will overcharged won any or all cells because of the force its thorn in the path before the VMS can disperse the over charge voltage.
That's funny I read my post canvas Spurs
Can disperse ha ha
Love talk to cats
Talk to text
Ok
 
Lol, talk to text. I thought you were having an alcohol induced stroke there for a moment. :lol:
 
I agree that it shouldn't be done but I wasn't really clear.
My friend did a mistake and we want to know if it has done major damage to the pack or not. It didn't burn down anything and he won't use that charger again.

It's li ion.
 
eikido said:
I agree that it shouldn't be done but I wasn't really clear.
My friend did a mistake and we want to know if it has done major damage to the pack or not. It didn't burn down anything and he won't use that charger again.
Then he is probably OK. That is, after all, what they are designed for.
 
Agreed. If it stepped in when it should have then hopefully no harm done under those circumstances. I would have metered the pack immediately afterwards to be more sure, but it is what it is.
 
Any question about pack / cell SoH is best answered with a controlled CC load test, even a crude one.

Really only way to tell, easier and lots more straightforward than benchmarking ESR
 
eikido said:
If I ever did a mistake and used a 16s charger on a 14s battery pack, what would be the consequences? Would a some what advanced bms protect from charging over 58.8v?

Because using a 16s charger on a 14s battery pack would charge each cell at around 4.8v which is not good at all. I wonder if the bms would protect it.

it depends on the bms.

if:

the bms has a cell-level hvc that actually works to shut off the charge port,

and

your charger is connected to the charge port (not the discharge port),

and

all the sense wires from the cells are actually connected to the bms and dont' have any problems (so the bms can actually tell what voltage the cells are at)

and

the bms's charge port fets are designed to handle the voltage of the charger you use (so they don't fail, which often results in permanent-on condition)

and

the bms's charge port fets actually work (aren't stuck on, so they will cut off the charger from the battery when commanded)

then

the bms should shut off charge as soon as the first cell reaches the bms's cell-level hvc.


if any of those conditions fails, the bms will not shut off the charge, and cells will overcharge.

also, they will only overcharge evenly if the cells are all exactly the same, which is generally not the case in an ebike battery. if some cells have less capacity or higher internal resistance, they'll overcharge more than other cells...how much more depends on their capacity/resistance relative to the others. there's a point at which cells can't handle that any further, and will object dramatically to it....

that's when things get sad. :(
 
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