Are EV cars ready?

What puts me off EV conversion is all the kit is low voltage. That Bi-turbo is 96 Volts. All the OEM's use 400V as that's about the limit for the power electronics (next generation could be 600-800V). The problem with low voltage is the high current required to obtain the same power output. Power loss is proportional to current squared. So running the same power as a Leaf at 96V instead of 400V means it has greater power loss in the motor's copper winding. All that power loss makes HEAT and no go.

2nd thing is all the motors lack revs. This maybe a slight benefit in matching to the gear box but OEM don't use a gearbox (saving about 75 Kg = lot of batteries). They simply have high revs (Leaf 18000 rpm) and a large reduction gear. Then they sacrifice top speed for off the line wheelspin. As they are rev limited in single gear they hit the limit while still accelerating hard.

Uses parts from here. I think this is the kit:

Interestingly it uses used batteries from the Smart Electric Drive:

I suspect that might be because of safety - 400V DC is no joke, and 96V DC is less likely to fry unsuspecting home mechanics.

I imagine retrofitting is easier if you're not replacing the gearbox. Plus it doesn't change the 'feel' of the car as much - for those who like the manual gears.

Theo

For the same CSA cable, yes. But 400V will need thicker insulation and the battery loss will be the same in Watts. Low voltage semiconductors also tend to better at handling the currents.

Again you would need 1/4 of the windings at 4 x the CSA. The overall loss should be comparable. If they use the same 400V motor then I agree with you.

Can't really comment, this is down to the torque and max speed characteristics of the motor.

It certainly is no joke but far safer than AC. This is one article I came across:

Example: "Either AC or DC currents can cause fibrillation of the heart at high enough levels. This typically takes place at 30 mA of AC (rms,

60 Hz) or 300 ? 500 mA of DC"

And: "Let-go current is the highest current at which subject can release a conductor. Above this limit, involuntary clasping of the conductor is present. It is 22 mA in AC and 88 mA in DC".

There was a spat between Tesla/Westinghouse and Edison over the dangers of DC vs AC:

And

Trained dealer technicians are no more resistant to the effect of 400V DC than a home mechanic.

Don't have much control over a battery, they are all inherently DC.

EV 3 phase "AC" is only present when the motor has power and vehicle is in motion or on rollers. For many EVs calling it AC is a misnomer as it's bi-directional DC. The DC polarity feed to the motor is swapped over by a transistor "bridge". This why Dyson call their motors "digital", the feed to each phase is binary either on or off or on but reversed.

Town Gas is largely hydrogen. Town gas was made from coal.

A shame Scargill wrecked the coal industry, especially as our natural gas resources are running low.