I would want nothing to do with the big battery if that’s the quality you’re getting lmao
$350 for 60 sansmug 30QT 21650 cells is a steal though
best way to connect the 2p groups
they need to be connected into 2s4p and then into the rest of the pack
i want to spread the current load as evenly as possible
edit:
here is my current plan but i dont know if its the best solution
(sorry that its very messy)
TeachingTech just made a pretty decent video on battery basics
Only things he missed were rounding nickel edges and slightly odd fishpaper placement. However, the pack is just sitting in a printer, so not a huge deal
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Yeah this is why people don’t try to do what you’re doing 
What a mess
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i did mention that to the person i am building the battery for
sadly it is very space sensitive so this was the only way of doing it
is the way i put above the best way of doing it?
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I mean I’d probably connect the top two in parallel and the bottom two in parallel, then the two sets in series
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thats what i was thinking but was worried that i need to spread the current evenly
as in i should connect in parallel and then do one wire from each side of the parallel group to the next one (series connection)
That seems excessive to me
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ok thanks a lot
will post some pics when done
I thought I’d heard of charging a single pgroup through the balance wire with 5v charger. I know it’s probably dumb, buuuuuut ?
Not probably, definitely.
A 5V USB charging adapter will fry a 4.2V cell and it will essentially be short circuited by the cell when you start charging. Some of these adapters do not like being run at higher than their 1A or 2A (typical) rating and will shut off.
The balancing wires are also not sized for current levels this high. Balancing is typically done at under 100mA for most esk8 packs and forcing 1A-2A thorough those tiny wires is not recommended.
Don’t do it.
Why do you want to charge individual cells/p-groups like this? In theory it can be done with the right type of power supply or 1S charger set to a very low current level.
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Trying to find a lazy way. Safety 3rd though, I will heed thy warning
When I charge it always ends up .4 under the others
When you charge up fully, is the total pack voltage 50.4V or 50.0V?
I had my cutoff set at like 4.1v so I’d have to check
Pretty sure it’s the pgroup but the bms starting acting crazy so I just went skiing 45mph on superball sized ice chunks @JoeyZ5
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If you mean directly using a 5v power supply such as a phone charger to charge a p-group, then no, that is bad and should never be done.
If on the other hand you mean using a single-cell 5v-input charger circuit like a TP4056, then yes, that will work great.
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Yea… sure, that’s what I meant.
Would still need to disassemble and use for one cell at a time?
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You will at the very least need access to the balance connectors.
If you’re hunting a dead cell in the p-group then you’ll need to dig down into the pack to reach the individual cells.
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Dig = remove pack, take apart? Or poke around?