[Dillzilla]

I have a motor and controller that runs at 385v and was planning on running Nissan leaf batteries. to provide the proper voltage i would need 50 batteries. i was wondering if there was a way i could run with half the batteries and step up the voltage through a buck converter of some sort.

 

[brian_]

That's how most non-plug-in Toyota hybrids work. They have a NiMH battery at 288 volts (nominal) and to run the motor at higher voltage there is a voltage doubler at the input to the inverter.

And the usual term for those sections of the Leaf battery is "modules" - there are 48 modules, each with four cells in a 2S2P configuration, in the 24 through 40 kWh batteries.

 

[Dillzilla]

That's how most non-plug-in Toyota hybrids work. They have a NiMH battery at 288 volts (nominal) and to run the motor at higher voltage there is a voltage doubler at the input to the inverter.

And the usual term for those sections of the Leaf battery is "modules" - there are 48 modules, each with four cells in a 2S2P configuration, in the 24 through 40 kWh batteries.

is there is one in particular that would be recommended? preferably one that isn't out of a hybrid if possible just for availability reasons

 

[MattsAwesomeStuff]

That's how most non-plug-in Toyota hybrids work. They have a NiMH battery at 288 volts (nominal) and to run the motor at higher voltage there is a voltage doubler at the input to the inverter.

In Toyotas, far as I've seen, the voltage doubler is only used when it's called for. Otherwise it runs at the standard pack voltage. And, the voltage doublers in, for example, the Priuses, are considerably limited in current they can handle compared to the rest of the inverter.

Some guys have thought about using them to gain higher speed, and changed plans when they saw the lacking performance.

Not sure if everyone would feel the same way, most people seem to just want to be able to go reasonably faster, they're not looking for performance.

IIRC Johannes has got field weakening working, but it's a bit buggy and the openinverter community has been going over it with him with what works, but aren't sure exactly why it works or if that's a best practice. It's a software thing.

 

[brian_]

is there is one in particular that would be recommended? preferably one that isn't out of a hybrid if possible just for availability reasons

I have no idea what might be available, beyond the Toyota components.

In addition to the limitations which Matt mentioned, the Toyota doubler is integrated with the inverter, so it is not likely a viable choice for another vehicle. The Toyota part is more significant as an example of the same approach being used than as an source of actual parts.

Porsche is equipping the Taycan with a high-power DC-to-DC converter to shift the ~400 V available from DC charging stations to the ~800 V needed to charge the vehicle's battery. This is presumably wildly expensive, and may not function at a lower input voltage.

 

[MattsAwesomeStuff]

the Toyota doubler is integrated with the inverter, so it is not likely a viable choice for another vehicle.

Actually, from what I understand, it's not.

Under the inverter hood is kind of like under a car's hood. There's discrete assemblies of this and that. The doubler is a whole chunk of board and stuff that you can either use or not use. You don't need the rest of the inverter there to use it.

That said, also under the hood there is a ~1000W 12v DC-DC step-down power supply, and the control board, and the power board, and the cooling plate, etc. Lots of it is usable and it's not all that large.