Discharge only BMS wiring

Is it possible to make a BMS for discharge purpose only? I want to bottleneck the output current from a lipo battery.


Balance wires won’t play any role in this setup. Is this correct?

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What esc are you using?

You could use a regular BMS and connect the charger straight to the battery’s cells, skipping the BMS.

I don’t recommend that

Or if you mean a disposable (not rechargeable) battery, you don’t need a BMS at all.

That image won’t work because it has no way to drive the gate of the FETs. At a minimum, you’d need a B+ connection, aka one of the balance wires. But I don’t know if the BMS are wired to allow that, it’d probably be specific to a particular model of BMS. You’d have to try it out…

Do you just want a circuit breaker?

It’s a portable charger I’m trying to also use for charge and ride.

6s Lipo -> CC/CV Step up converter 42v -> charging port.

It works well for normal charging. But when I’m using it to charge while riding, it blows the 25A fuse on the step-up converter. I’ve gone through 4 fuses already and I’m thinking that the Lipo discharges more amps than the converter can handle when it’s charging while I’m riding the board. Hence I want to use a BMS to control the output current.

I could wire everything up with the BMS normally but I want to keep the jst connector on the lipo’s balance wires because I’m using the B6 imax charger to charge it. Unfortunately I don’t have a 7-pin jst to create an adapter.

What CC/CV converter do you use? How much is the charge current? The current taken from the LiPo depends on the charge current required. If you reduce the charge current, that will reduce how much the LiPo discharges as well. I don’t think you actually need a BMS.

Maybe the problem is that if you charge while riding, the battery pack sags as you add throttle. The CC/CV converter then needs to reduce the output voltage to keep the charge current constant. I guess that maybe it doesn’t react to the sudden voltage drop on the battery pack quickly enough and that temporarily increases the charge current, creating a spike. As a result, more current is pulled from the LiPo and that blows the fuse.

I use this step-up converter.

I think this is it too since the Lipo is capable of putting out large amounts of current. So I was hoping if I used a BMS only capable of discharging 5A - 10A, it’ll limit the amount of current that can be drawn by the converter regardless of the sudden battery sag due to load while riding.

BMS won’t regulate the output current. It will cut-off the power supply completely on overcurrent… which may not actually be a bad thing in your case. It would just temporarily stop charging. I’m still not sure that’s a good setup since BMSes are not designed to handle overcurrent on regular basis.

Honestly, I don’t fully understand how this works, but I know some people have been successful.

What output current is your booster set to?