Just starting, need input

I am just thinking about the EV thing, learning rapidly and could probably make this post so long that no one would read it, I’ll restrict myself to immediate questions and try to get specific.

I will build myself an EV, hopefully a car but I have no urgency attached to the task. I will start with a small scooter as the costs involved are better and it’s only really a learning project, the lessons learned will be equally applicable to any vehicle I suppose.

Battery types don’t seem to be much of a problem, there is enough on here already to answer my questions for now, LiFePO4 if I am feeling rich but NiMH will do for cheap. The first thing I am struggling with is information about motors, it would seem that the best way to go is multi phase AC and a controller with regenerative breaking capability, that seems also to be the most expensive, permanent magnet for good weight/power ratio. It seems that for small non-regenerative systems a brushed DC motor will make for easier design and a lot lower cost. Is that a reasonable appraisal?

So specifically I have a 650 watt 24 volt DC motor rated for 3100 RPM, max current 110 amps. From reading here and other places I figured this would be fine for a not too nippy but functional moped type thing built on the lightest puny 50cc moped that I can get hold of. I assume the 650 watt 24 volt (26 amps) is for continuous use with 110 amp rating being for short bursts with meltdown occurring if the “short bursts” is ignored.

Have I got my evaluation right here, I really have no idea?

So to go with this (brain fussed at this point) with a 48V, 20Ah LiFePO4 pack, cost around £200 to £250, it needs to be capable of 3c discharge to allow me to use the full capability of the motor? There is precious little information about the controllers. If I have a 24 volt motor can I use a 48V pack, is that a normal thing to do? Is the 24 volt rating a continuous rating and what fixes that voltage, can I go over that for accelerating to keep the current down? It’s been a long time since I did any motor theory.

Looking for some good links and reading at this point

Other things that are bothering me, not as important.

In the dim and distant past I used to do a lot of slot car racing. In order to make motors work better I used to shim the magnets to make them closer to the rotor and I used to alter the timing of the commutator to optimise forward power, there was never any need for the motor to perform rotating backwards, this altered the timing of the motor, the usable rev range was reduced but the power, in band was much improved. Are the motors that are made for electric vehicles already optimised using these methods? I know that on small motors you could easily double the power output for a motor using just the two methods above, if not are they manufactured such that these mods could be performed. Moving the magnets will normally necessitate grinding the rotor laminates but this isn’t a problem as I have a crankshaft grinding machine that will allow me to do this. It would also probably mean having to filter the air flow through the motor as the tighter tolerances mean that any crap gets in it self destructs, not a pleasant occurrence.

Hmm, it seems to be droning on a bit, I’ll stop now, think some more and wait for any responses.

Bit of a long winded first post, sorry about that.