Ford Focus

[timpootle]

*sticks head above parapet*

I'm collecting data to convert a Ford Focus, to have motorway capable speed and as much range as I can (it has to be an improvement on the Berlingo, which is already Quite Good).

I chose the Focus as is has been the best selling car in Britain for the last ten years, and I want electric vehicles to become 'normal'. To this end I intend to document the conversion in such a way that any engineering company or garage could do it for anyone, not just a DIYer.

I'm posting now in case anyone else is further down the same road, and we might share data and machining costs.

So... any offers?

[qdos]

Not with a Focus, but not a bad choice really. Plenty of them about. Will be interested to see how you get on with it if you do it.

[MalcolmB]

Good luck Tim. Glad to see I didn't put you off

[ChopperMan]

Hi Tim, apparently there are a several thousand flood damaged vehicles after this summer, 5 year or older Focus's with damaged engines can be had for silly money! Speak to Stuart at MEV Ltd, I'm sure he would be able to point you in the right direction.

How are you calculating the amount of power needed for motorway speeds?

This online tool is interesting but there aren't a huge number of motor/controller combinations to play with http://www.evconvert.com/tools/evcalc/

As you know I'll be watching your progress with great interest

Cheers,

Ian

[EVguru]

12Kw from the battery ought to give you a 60mph cruise on the flat. That's a typical figure for a car in that class. 45Kw should take you up to around 100mph, but you need more for acceleration.

What battery chemistry were you proposing and (related!) what is your budget?

[timpootle]

Thanks for your advice Paul- all contributions gratefully received ;-)

I'm confused by your comment on power required:
12kW for 60mph on the flat- yes, I understand.
45kW for 100mph- this is nearer the numbers written on the back of my envelope
more for acceleration- This is the bit I don't understand.

If 45kW is good for 100mph, then 0-30 acceleration should be adequate, yesno? I'm a little worried about 50-70 acceleration. This seems to be a weak point of conventional EV design.

I am no longer the speed-freak I once was. If I were, I'd be copying Russ Sciville's Lotus Elise. All I'm after is enough to keep the horns at bay at the traffic lights.

Regarding battery chemistry, I'm after long range, which means lithium, which means expensive, which means bank loan. I am prepared for this, and believe it is worth it.

[EVguru]

I'm confused by your comment on power required:
12kW for 60mph on the flat- yes, I understand.
45kW for 100mph- this is nearer the numbers written on the back of my envelope
more for acceleration- This is the bit I don't understand.

If 45kW is good for 100mph, then 0-30 acceleration should be adequate, yesno? I'm a little worried about 50-70 acceleration. This seems to be a weak point of conventional EV design.

Yes, low end acceleration would be fine, but as more and more power is eaten up in air resistance, your acceleration will drop off. That's why you need more peak power than is often recognised. My Scirocco had a theoretical 130Kw on tap and would still pick it's heels up at 70mph in full power mode. In fact I very rarely used it and ran the controller in it's 'Vallet Parking' mode most of the time. Performance was then still acceptable on a busy M1 with trafic at 60mph.

Regarding battery chemistry, I'm after long range, which means lithium, which means expensive, which means bank loan. I am prepared for this, and believe it is worth it.

The Tundersky Cobalt chemistry seems well proven and stable. Their Manganese has demostrated problems and Iron Phosphate, who knows! Rather worrying as I want to buy some.

I'd say you need a minimum voltage of 144 and my preference would be to go higher, although that would mean putting yourself on the six month waiting list for a Zilla controller.

If you went for an AC drive system, then you'd be looking at 180v minimum on something like a Siemens system. Watch out though because although they may state that a controller will work down to quite a low voltage, the power available falls off in proportion.

[timpootle]

How much power does valet parking leave you with, then?

I think your Scirocco is lighter than the Focus, especially when I have filled it with batteries.

I don't need it to 'pick up it's heels above 70', but I need to plan for enough power to get there at all. It's a difficult balance, isn't it?

45kW is looking About Right, so far. Still tossing up between AC and DC. Series motors always look a bit agricultural to me, whereas brushless DC motors are pure magic (as in I don't know how they ever work..)

I want this project to be something anyone can ask their local garage to do, but still give outstanding range.

More envelopes, please!

[ChopperMan]

Hi Paul,

When you say "12Kw from the battery ought to give you a 60mph cruise on the flat." am I right in assuming this is not the power out of the motor, just the electrical power in?

I only ask because D & D are quoting power out of their ES-31 Sepex motor taking into account electrical looses, 72 volts, 165 amps, 12.0 HP at 1750 Rpm.

So power in would be more like 72V X 165A = 11.88kW @ 745W per HP = 15.9hp?

Have I understood this correctly?

Cheers,

Ian