Question about controllers that you can adjust the voltage?

[alpharalpha]

I am looking at a front hub kit that the seller tells me I can adjust the voltage on it, is anyone familiar with this? I have been using a 27v x 30ah pack with a brush motor and while I have the other 3 cells to make it 36v the current setup works for me. Has anyone used a controller that the voltage can be adjusted like this, is it reliable etc?

 

[larsb]

All bldc controllers have a range where it funtions, even the simplest ones have settings for undervolt limits etc. Don't know if all goes as low as 27V though, but if seller says it's ok then probably this is the case

It's reliable but you will (off course) only get 27/36 % of the normal speed for the kit if you lower voltage. It will also lack power since the top end of the motor capability is not used at 27V.

I think it's upgrade time to 36V if you buy the kit.

 

[amberwolf]

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[alpharalpha]

All bldc controllers have a range where it funtions, even the simplest ones have settings for undervolt limits etc. Don't know if all goes as low as 27V though, but if seller says it's ok then probably this is the case

It's reliable but you will (off course) only get 27/36 % of the normal speed for the kit if you lower voltage. It will also lack power since the top end of the motor capability is not used at 27V.

I think it's upgrade time to 36V if you buy the kit.

I can upgrade to 36v, have the other 3 cells. I asked specifically about 27v and he replied " Setting the voltage to 24v is enough to get the kit to work with a 27v battery." As I am new to brushless does this seem reliable?

 

[larsb]

Do you have SLA batteries or how do you get to 27V?

Link to kit would help.

 

[alpharalpha]

I built the pack using 9 Prismatic LiFePO4 3.2V/30Ah that I managed to fit into a Jandd Rack Pack 2. The pack's BMS controls each battery so can be different voltage "BMS for 3~16 LiFePO4 cells in series."

 

[larsb]

Ah, i was confused about the voltage since 9s lifepo4 isn't 27volts, and 12s isn't 36V nominal.

Anyway you'd have to get the controller limits adjusted, you just need to confirm with the seller that it can be done within the limits for lifepo4 cells.

12s lifepo4 would be around 30V (2.5v/cell) undervoltage limit (corresponds well to 10s lipo limit) and 44V overvoltage limit (too high for 10s lipo limit which is the norm)

Good luck