Using a 36V lithium battery with a 24 v controller ?

[ChristianR]

Hi,
I have a 36V 12Ah LiFePo4 battery, but I would like to use it for running a 24v motor + 24v controller.
Most of the time (when I am using a 24V battery), I measure a maximum power <800W, and intensity max < 35A.
I can't change the controller.

So is it possible to use the 11 pin plug (available for the balance board charger) of my 36v battery and to connect 2 wires only on it, to obtain 24Volts? (pin 1=gnd + pin 8)
- may it dammage the battery if I use only 7 cells during discharge (7x3.6 =25.2V) among the 10 available cells (36V) ?
- may it damage the balance plug or thin wires?
thanks

 

[jateureka]

You'll likely melt the balance wires if you try to run your motor off them, they are way too thin to carry that sort of current.

If your 24V controller can't take the 36V (capacitors are rated below 45V) then buy another controller rated for 36V, or you could buy a 24V BMS and charger and re-configure your 36V battery for 24V.

 

[dogman dan]

Yeah, it's not going to work as you want it to. You will need to permanently remove cells from your battery to use it as 24v. Most likely your best approach will be replacing the controller with a 36v one. But you say that can't be done.

That pretty much leaves replacing the whole thing, motor and controller. Or rebuilding the battery with an 8 cell bms and 24v charger. Ping could set you up with that stuff, just ask him in an email.

 

[ChristianR]

Or is it possible to buy somewhere a DC-DC converter (36V in -> 24V out, but powefull) ?

 

[jateureka]

Maybe, try google, but at those sort of currents it's likely to cost more than a new setup.

Have you checked to confirm your 24V controller can't take 36V?

If the controller is built into the motor then you could disconnect it and run the motor wires out and use two external controllers - one for 24V and one for 36V or just use a 24V controller that can also handle 36V but mind your LVD some other way.