P38A EV Conversion / Hybrid conversion - Pie in the sky thinking

styleruk said:

This has got my attention. I've been driving EVs for over 10 years now to commute, have an electric motorbike too...all these alongside my petrol classics and petrol big motorbike for proper touring. But, it's got me thinking about hybrid for my 1985 petrol 90. I'd hate to lose the motor but love the idea of commuting on EV...I get to charge for free at work and home.
One way may be to fit in hub motors, there's a company that has developed these, (bedeo). That would work in that you'd fit the battery underneath and out of the way (if possible), then maybe just 2 rear electric motors. Even if you go with a relativly small battery to give you 100miles (yeah right, more like 80miles if you are lucky), that would do the trick for me. I'd be able to do local run arounds and even my commute and charge up from solar at home. I'd have rear wheel drive only, but hey, if I want to go further or tow something, fire up the old 2.25 70hp clanker!
- No idea how you'd keep drive from engine for the rear wheels
- You would not get regen...I guess, but that's not problem.
- batteries underneath might mean less off road if you like that sort of thing.
- Currently they only sell to fitters, so you'd not be able to do it yourself....that means it'll cost a lot to do.


Food for thought.

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styleruk said:

yep, another EV conversion. There's 100s of them. But hybrid is a different in many ways. firstly, you keep the engine and can drive all day (these days), as you can pop into a petrol station. With the addition of doing short journeys using EV, it's not about power either, a lot of these full EV convertors charge £60k for a complete mod and it gives you loads more power etc...but for me, I'm happy with the 70hp I have, so a low power motor somewhere would be a good solution. cost will be much lower, challenges are harder, they certainly are harder for a company to sell the product. It suits a home made project more.

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pwood999 said:

Whatever route you take, do a project thread like "Alibro" has done for his Freelander.

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Grrrrrr said:

Yep, we'll all be there one day unless a hydrogen v8 becomes available.

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Montyjohn said:

I wouldn't count on it.
You'd need a tank the size of your car.

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Datatek said:

You can expect 250 kms on one kilogram of hydrogen, a tank about the same size as a normal fuel tank is needed but a good bit heavier as the gas is at 700 bar..

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Montyjohn said:

Not convinced by your maths.

Hydrogen is 33 kWh/kg
Petrol is 13 kWh/kg

Let's assume the same thermal efficiency from the engine. My P38, on a really good run will achieve 20mpg (that may be optimistic).
Which is 4.4 miles per litre.
One litre of petrol is 0.74kg
So about 6 miles per kg of petrol.

So the most you can expect from a P38 V8 hydrogen is 15 miles per kg.

So let's assume you want a range of 400 miles to roughly match what a P38 can do. So you need 27kg of hydrogen. Seems pretty light.

Now, let's assume we don't use cryogenic cooling, because, that's insane.
You are then looking at about 40g/L for storage at 700 bar.

So that's a 675 litre tank. So it would need to be multiple tanks, all able to hold 700 bar.

I just can't see it happening.
Yes, you could limit it to much more efficient engines than the V8, and you could half the above figure.

But really, hydrogen will only work on a fuel cell car which has a much higher efficiency.

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Montyjohn said:

Not convinced by your maths.

Hydrogen is 33 kWh/kg
Petrol is 13 kWh/kg

Let's assume the same thermal efficiency from the engine. My P38, on a really good run will achieve 20mpg (that may be optimistic).
Which is 4.4 miles per litre.
One litre of petrol is 0.74kg
So about 6 miles per kg of petrol.

So the most you can expect from a P38 V8 hydrogen is 15 miles per kg.

So let's assume you want a range of 400 miles to roughly match what a P38 can do. So you need 27kg of hydrogen. Seems pretty light.

Now, let's assume we don't use cryogenic cooling, because, that's insane.
You are then looking at about 40g/L for storage at 700 bar.

So that's a 675 litre tank. So it would need to be multiple tanks, all able to hold 700 bar.

I just can't see it happening.
Yes, you could limit it to much more efficient engines than the V8, and you could half the above figure.

But really, hydrogen will only work on a fuel cell car which has a much higher efficiency.

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