Battery protection board or...... balance wires?

ThomasEekels

10 mW
Joined
Aug 18, 2019
Messages
27
Hi All,

I have a bunch of 18650 3000mah li-ion cells doing nothing, so I want to build some packs for my drone.
I am planning to make 3s2p packs but I lack some theory for charging etc.

If I connect them in 3s 2p, I can add a battery protection board, but does that also take care of cell balancing during charge ?
These boards do not come with balance connectors. Is it a separate function ?

My lipo charger can do both , balance or non-balance. It has balance connectors and xt60. My standard drone lipo has both too.
So, If I add a battery protection board can I do without balance wires and charge without ? Or should I add balance wires as well .. ?

Advice is appreciated.
Thomas
 
Most of the cheaper BMS boards balance but only at full charge and the balancing current is very low. Most of the time, this is enough. If the drone has a low battery cutoff, you might just skip the BMS completely as 3s is not as likely to have a bad cell go undetected.
 
So I can just skip the board, add balance wires and let the charger do the balancing ? It is the Imax B6 ....
 
I like to know so I would also have balance or Sense wire for checking and balance and knowing. Or a Bluetooth BMS. As I guess these are not new cells. Or
Put an alarm on it for lvc.
 
They are brand new. I bought them to rebuild my e-bike, but it is Bosch, so that does not work. Now I seek new destination.

Can I just add the BMS and also add external balance wires ? will the balance charger not interfere with the board's balance ?
 
The boards you are talking about have **zero, zip, nada, nothing** to do with balancing.

Other than providing a structured wiring harness for paralleling, with fusing for protection against bad cells / packs frying the whole lot.

There are dedicated balancers, BMSs that do balancing as well, and balance chargers, beyond just doing the job manually.
 
I know we are talking about three different methods in this thread with two different chargers. What are the power of your flying machine
 
Both, is not a bad approach. The balance wires may be used only for monitoring, without actually putting them on a charger that reads out volts of each cell.
 
ThomasEekels said:
Can I just add the BMS and also add external balance wires ? will the balance charger not interfere with the board's balance ?

That should work. I don't think a typical BMS board will interfere with the balance charger. There may be a problem if you tried charging through the BMS and had the balance charger attached.
 
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