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Making battery balancer?


#1

Who knows electronics?

I’ve got 48 lg hg2 cells for a 12s4p pack and want to omit the bms. They are the safest li-ion chemistry and don’t even have a gas release valve and my pack will be big enough I won’t be fully charging it.

Anyway I plan to have both sides of the 4p accessible so I can monitor and balance by discharging. I’ve seen this but it’s just for monitoring:

With my simple understanding of ohms law I feel I could reduce the circuit resistance and that will incrwse the current …thereby discharging any high voltage cells in the pack. No?


#2

Why not get a smart BMS, which stops at 4.15 and balance cell’s there. And bypass discharge?


#3

I want to keep it simple and feel this pack is big enough and the cells safe enough to do it this way. …no more room on the deck


#4

Just increasing current draw will only cause the lower voltage cells to discharge more current, and that will cause issues potentially damaging your battery pack. Unless you get a 12 cell balance charger your going to need a BMS. I highly recommend a bms as it allows just plugging in a single connector and you don’t have to worry about balancing the cells.


#5

Now I bulk charge 12s and balance through the addition of battery medic-like devices connected to the balance leads. I like it because I can keep all my batteries connected in series on the board and use one plug to charge. I want to do the same with this li-ion pack but make the dischargers/monitors that I will attach to the 4 cells in parallel

I want to increase current draw from the 4p to balance


#6

It would work… As long as you don’t over charge or discharge too crazy then the parallels would stay pretty much where they are I would check them once every hundred miles and manually balance them every so often.

Like I said it would work but it’s not ideal but I’ve seen it done before on E bikes

I don’t know people act like batteries are so sensitive. When you charge the pack just make sure to charge at a pretty low amp rating… Like 1-2 at most


#7

I’m trying to find if I can change the circuitry and maybe Idecrease some of the resistance on a voltmeter so I can connect across the 4,get the voltage, and be discharging at once