Newbie battery balancing questions.

[Common_good]

Edited. Good catch

[andoug]

Thanks heaps

[Phillyboy]

I have a problem I am building my board and life got in the way and i was not able to finish it for a long time any way I just got the Moli cells 21700 in for a 12s3p for a set of Torque boards Direct Drives. They are 80 amps a piece. Would I get away with a 12s3p? What do you recommend?

[Common_good]

This is probably a question better suited to the battery builders thread but it seems to me like you’re asking a question that some rudimentary knowledge you should already posses (if you’re attempting a battery build) would easily answer.

I’d recommend starting with thr battery basics thread to make sure you understand the foundations before diving into building a pack. You should be able to, at a minimum, predict what your pack will be capable of if you understand cell specs and the implications of constructing parallel groups with a given number of cells.

Battery Basics for Beginners Wiki [Serious]

I see the same question being asked by many newcomers here so I would like to shed some BASIC info on batteries used in esk8, notation, configuration, ratings, etc. Battery Notation Common battery notation you keep seeing or will see is a (XX)s(YY)p battery with (ZZ) cells: XX is the number of cells you have in series ( s ) type connection. YY is the number of cells you have in parallel ( p ) type connection. ZZ is the actual battery cell type used. At the time this article was writt…

[Tender]

Going through same process with my 12S9P pack.
Day 2 and we are in 0.045V range from each other from 0.113V

[Tender]

0.022V now, Think i will give it one more day

[Gael]

Hi,

Am
Having issues with my balance process, pack 1-3 are 0.070volts out of balance. My LLT BMS is acting weird and when I plug my board cell 1 drops to 3 volts consistently despite really being a lot higher. My charger dosn’t tickle charge anymore an charges in burst of 1000 watts and never goes below 800 watts until the max voltage is reached on cell 1-3 and. Am leaving it on the auto balance setting for nights and still same result after pack has been balance. Weird sporadic voltage on cell 1 no tickle charging only bursts of high currents.

[glyphiks]

I’d put money on there being broken welds on thst first group

[Gael]

The board discharges perfectly and the imbalance gets better as I discharge the board I don’t have any cutoff or anything it’s dead smooth and I push it a lot. Maybe bad balance lead that’s making my BMS trip and overcharge the 1-3 pack ? The thing that is scaring me is that the charger dosn’t lower the amperage threw the charge it stays charging on max power until max voltage is reached on pack 1-3.

[glyphiks]

I would be inspecting those first 3 groups very carefully. If they are charging faster than the rest, its very likely that they have broken welds or dead cells.

Problem now is that if they have been this way for several cycles, there is quite a big possibility that the cells in those groups have gone under voltage and have the potential to be damaged.

You really need to open it up and inspect

[hummieee]

Or just throw it out to be safe.

[poastoast]

but we haven’t assessed the damage yet

[Gael]

Found the issue, it came down to lowering the equaliser starting voltage from 4000mv to 3600mv now it’s balancing right and the charger correctly lowers the amps at higher cell voltage like it’s supposed to.

[glyphiks]

Seems like treating a symptom rather than the issue.

A healthy pack shouldn’t be that far out of balance and starting balance at storage voltage is a band aid, not a solution.

[Gael]

The balance starting was at 4.0v witch it’s pretty high should be more around 3.7-3.8 I will try to put some cycles see if it solves the imbalance.

[glyphiks]

I disagree but you don’t seem to care too much anyway. Good luck.