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Low voltage systems

Posted: Jun 12 2019 1:21am
by agniusm
So everyone is building and lowest system voltage 99% use is 36v minimum. I would like to use 24V controller for 2kw vehicle for speeds upto 30kmh with hub motor and chain reduction to differential. Any cons to that?
I see only benefits like using tesla module without any modifications and electronics are available for 24v widely, guess cause of forklift market.

Re: Low voltage systems

Posted: Jun 12 2019 1:38am
by amberwolf
There's a few discussions about high vs low voltage systems that have all sorts of details, but basically it comes down to: the lower the voltage, the higher the currents have to be to get teh same power.

2000w / 24v = 83.3a so you'll need a battery and BMS (if any) that can handle that kind of current, and wires that can do so too.

Re: Low voltage systems

Posted: Jun 12 2019 1:42am
by Drunkskunk
Massively thick wires, Special high amperage controllers, much more expensive switching gear, putting more strain on batteries by drawing high amps.
Volts X Amps = Watts. It's easier and cheaper to handle higher voltage than it is to handle higher amperage.

Other than that, no real reason. Watts are watts. I've built a handful of 24 volt e-vehicle creations.

Re: Low voltage systems

Posted: Jun 12 2019 2:51am
by agniusm
amberwolf wrote:
Jun 12 2019 1:38am
There's a few discussions about high vs low voltage systems that have all sorts of details, but basically it comes down to: the lower the voltage, the higher the currents have to be to get teh same power.

2000w / 24v = 83.3a so you'll need a battery and BMS (if any) that can handle that kind of current, and wires that can do so too.
Drunkskunk wrote:
Jun 12 2019 1:42am
Massively thick wires, Special high amperage controllers, much more expensive switching gear, putting more strain on batteries by drawing high amps.
Volts X Amps = Watts. It's easier and cheaper to handle higher voltage than it is to handle higher amperage.

Other than that, no real reason. Watts are watts. I've built a handful of 24 volt e-vehicle creations.
OK, so basically it only boils down to required power. In my case 2kw is not that much and 83A is low current.
I stopped discharging trough BMS long time so that is no problem too. Using welding cable on some of the projects and it works great