Electric Assist Project: E-charger (2000 Subaru Outback)

[bustedprop]

I really like this concept and would love to try it myself. When I first read your post I thought "yeah, why the heck do you have to buy a new vehicle to have a PHEV?" I think it would be great if you could just bolt on a kit that would swap out the A/C compressor with 5-10hp electric motor. I envision something with a similar clutch as an A/C compressor that would allow you to turn the system on and off as you wish. Any idea of what kind of range extension or mpg increase you might get with an extra 225ah?

[Dr. Jerryrigger]

Originally Posted by bustedprop

Any idea of what kind of range extension or mpg increase you might get with an extra 225ah?

Well lets say we have a 25% mechanical loss (low end guess), so that brings us down to about 170ah, at 45V that's ~7.6kw hours, or about 10hp hours.
That's roughly the energy you get out of 1.5 gallons of gas per charge.

[brucey]

Patrick: Yup. The AWD clutch pack (center differential) requires the engine to be running while moving. A big disadvantage when you want to hypermile.

Daox: I'm not attached to regen really, but I was thinking simply slowing down without brakes (gearing down) it should still regen? I also don't know how much regen amps my batteries can take. As far as why them, I know they're proven and they're cheap is why I'm going for them. Plus, I can fit all 8 without losing any real trunk space:

[Daox]

I do think higher voltage would be a good idea. Ask any EV owner, the higher the voltage the better.

[Arragonis]

Originally Posted by brucey

... But when the engine does go into fuel cut, the electric motor is going to have to move the weight of the car AND turn over the (not running) engine it might be a bit much power to ask of it ...

This may be a stupid question. Would the electric motor have to overcome compression in the ICE engine or would it only operate as an assist option ?

[Clev]

I like the 'electric supercharger' idea. I was considering the Mars or eTek motors, but the AC12 looks good too.

If you want to go direct-drive, you could always toss out the RWD portion of your AWD and directly drive it with the electric motor. As a side effect, if your batteries were getting low, you could recharge them by regenning slightly while having the ICE power the car.

Remember that in either case, you'll have some heavier batteries on board. That means you could power the PS pump and A/C compressor with a small electric motor (90VDC treadmill motor, perhaps?) and toss the alternator for a DC/DC converter, reducing parasitic drag on the engine.

[RobertSmalls]

A battery pack with that many KWh would let me do most of my trips without firing up the ICE, assuming it can provide enough amps.

As the owner of a plug-in mild hybrid, I can tell you setup #3 will prove inefficient on short trips. The ICE ought to be moderately loaded or off for best efficiency, but with heavy assist, it's just going to be lightly loaded all the time.

I like the option of driving the rear diff with your electric motor. Alternately, delete the rear diff and drive one rear CV axle with your motor if that would get you a more appropriate motor speed.

[Dr. Jerryrigger]

I'm liking the rear wheel drive idea, you could just re-angle the diff so that the electric motor was where your spare tire would be (the back seat seem like a fine place for a spare anyway). I guess that would make it difficult to change the diff oil... well not to drain it at lest...
then there is the problem of the wheels connected to the ICE. It would be really nice to have locking hubs like on old 4WD trucks.

[brucey]

Well I should be ordering the motor/controller today or tomorrow! Here is hoping. The teardrop trailer needs to get finished (doors and trim still needed) before I can start on this project, so it still might be a week before I can start making any progress.

Robert: Yup, I know that it is an inefficient method, but it's also the most practical and should be the easiest to fabricate. I'll probably get a block heater at some point since the engine will never warm up under heavy electric assistance.

Jerry: Ayup, that's my back up plan if the belt method ain't work. Every thing seems to have advantages/disadvantages at this point. I'd worry about gearing with the single gear ratio though. I've also considered a pusher trailer, mainly so I can switch it easily from car to car, but don't know how that would drive either. It's worth looking into though.

[Arragonis]

Obviously mine was a stupid question.