GT4EC - The GT-Four Enthusiasts Club

General Category => The Chill Out Room => Topic started by: paul_gt4 on May 19, 2009, 09:06:10 pm

Title: Coyote you'll get good reading here, electric passat
Post by: paul_gt4 on May 19, 2009, 09:06:10 pm
http://etischer.com/awdev/ (http://etischer.com/awdev/)
Title: Re: Coyote you'll get good reading here, electric passat
Post by: fifegt4 on May 19, 2009, 10:09:48 pm
That guys seriously talented although I dont think I'll be trading the four for it just yet
Title: Re: Coyote you'll get good reading here, electric passat
Post by: flyingtele on May 20, 2009, 12:19:52 pm
Wow now thats an achievement! I'm not quite sold on its performance figures or the fact it can draw 20A at 240V just to recharge. Thats 4800 KVA. You'd need a heavy duty single phase power point and probably 4mm cable just to charge it, unless you happened to have a 32A 3 Phase outlet lol. Maybe he unplugs his oven to charge the car! And thats a lot of acid having so many batteries, which could be rather nasty if the car was involved in an accident  ;D

I'm curious as to what the gearbox came out of, looks like its from a 4wd car with a longitudinal mounted engine like a subaru or similar, you can see in the photo where the front half-shafts attached.

Edited as I have since found out about regenerative braking :)
Title: Re: Coyote you'll get good reading here, electric passat
Post by: paul_gt4 on May 20, 2009, 12:33:02 pm
Wow now thats an achievement! I'm not quite sold on its performance figures or the fact it can draw 20A at 240V just to recharge. Thats 4800 KVA. You'd need a heavy duty single phase power point and probably 4mm cable just to charge it, unless you happened to have a 32A 3 Phase outlet lol. Maybe he unplugs his oven to charge the car! And thats a lot of acid having so many batteries, which could be rather nasty if the car was involved in an accident  ;D

I like the way he's set up the inverter with a digital controller, able to control speed and torque. Also, having the choice of regenerative braking or freewheeling. I wonder how you would achieve regenerative braking with a 3 phase induction motor? My guess is feed power into one of the stator coils to induce current in the rotor, and use the rotors field to induce current in the other two stator coils?

Also, I'm curious as to what the gearbox came out of, looks like its from a 4wd car with a longitudinal mounted engine like a subaru or similar, you can see in the photo where the front half-shafts attached.

Concorde just flew over my head........
Title: Re: Coyote you'll get good reading here, electric passat
Post by: flyingtele on May 20, 2009, 12:43:07 pm
Concorde just flew over my head........

Well at least it was flying above your head and not at the same level!
Title: Re: Coyote you'll get good reading here, electric passat
Post by: Coyoteboy on May 20, 2009, 04:19:51 pm
Thats a fairly decent bit of DIY there, someone has far too much spare time on their hands :D It's fairly basic control stuff there and it must weigh a stack with the lead contents, and have an incredibly short range without damaging the cells.

However electric-only will never be a solution for anything other than city driving, and it's the old long-tailpipe problem, the emissions are still emitted at the power station, plus extra for charge/discharge inefficiencies etc. There's a reason Toyota did a stack of tests on all-elec vehicles and concluded they were actually worse for well-to-wheel CO2 output than a standard economical Diesel. For a decent life on the cells you need to maintain charge nowhere near min or max and that severely limits your range, or means you need to tow a trailer full of cells! Or invent a new battery type.
Title: Re: Coyote you'll get good reading here, electric passat
Post by: flyingtele on May 20, 2009, 04:48:42 pm
typically if the lead acid batteries used are deep cycle batteries then long discharge periods won't damage the cells as they are designed for that and have thicker plates and fewer of them so they can give slightly less current for much longer, as opposed to starting batteries (typical car battery) that has many more thinner plates to give higher peak current but because the plates are thinner then can be damaged as you say by extended discharge
Title: Re: Coyote you'll get good reading here, electric passat
Post by: Coyoteboy on May 20, 2009, 04:53:07 pm
I am aware (having just bought 4x 250Ah 12v batteries for a similar reason) but still feck all lifespan in comparison with what you'd want for a car, or even what you'd get from a NiMH setup. Cars need to be manufactured to last 200K miles at least, using DC lead acids you'd still need to replace them dozens of times in a cars lifespan. That's not too environmentally friendly :D
Title: Re: Coyote you'll get good reading here, electric passat
Post by: flyingtele on May 20, 2009, 05:03:01 pm
Not at all environmentally lol. I was watching one of those American car shows like monster garage or something like that. They did an electric conversion to some yank tank as a drag car. Used hundereds of NiMH batteries lol. They raced it down the 1/4 mile against a Dodge Superbee, fitted with a 426 Hemi! Needless to say, the Superbee beat the living cr@p out of the electric creation (finished the 1/4 mile with the electric one only halfway or so)
Title: Re: Coyote you'll get good reading here, electric passat
Post by: Coyoteboy on May 20, 2009, 05:33:06 pm
For anyone else who's interested - regen braking on an induction motor is done by reducing drive frequency to below mechanical frequency :D
Title: Re: Coyote you'll get good reading here, electric passat
Post by: peterp1per on May 20, 2009, 07:29:01 pm
Just buy a Prius, its much easier...lol  :o
Title: Re: Coyote you'll get good reading here, electric passat
Post by: bazza2541 on May 20, 2009, 07:31:14 pm
Just buy a Prius, its much easier...lol  :o

Fecking tree hugger hippy chick dope smoker car.
Grrrrrrrrrrrrrrrrrrrrrr.
Title: Re: Coyote you'll get good reading here, electric passat
Post by: Coyoteboy on May 22, 2009, 01:30:06 pm
:D I'm inclined to agree with Bazza on this one :D