Hi welcome to the forum.
There are heaps of variables with batteries (voltage, discharge rates (amps), range required,vehicle packaging restraints and as always $$$$)
So you need to work out what kind of performance you require from the car, range you want, a budget and then evaluate battery options with your requirements in mind. There are heaps of different threads on here talking about all kinds of batteries.
Because your using a tesla rdu which requires a voltage between 275-400v your best bet will be to look at oem batteries. There's lots to choose from depending where you live but the most common are out of a leaf, volt or tesla.
Tesla modules would give you heaps of range, are light and easy to package in a smaller car. But they are expensive. They also must be liquid cooled but you will be doing that for your motor/ controller anyway.
Volt batteries are cheap, tough, reliable and have cooling channels built in. There a little more blocky so packaging wont be as easy as tesla but not too bad. There biggest negative is there lower range (lower kwh per pack)
Leaf modules are cheap and small and are a little better than volts for kwh. There only air cooled not liquid so they can have longevity issues especially if pushed to higher c rates.
Thats really only a quick rundown on a couple of options. Lookslike you have alot of research ahead of you but its worth doing as the batteries are the most expensive part of the conversion.
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