BMW E30 Electric Conversion

RandomAccess

http://translogic.aolautos.com/2011/01/27/watch-an-electric-bmw-drag-race-a-tesla-roadster-and-win/

https://www.youtube.com/watch?v=iOo1TnWKVCg

Now I want to see it up against this v10 e30

http://www.youtube.com/watch?v=Q9dwf80-XGk

Embed doesn't seem to work for the second clip, probably because of the dash character?

Mr Benevolent

Impressive. Wonder what the range is like. Not the point of the car I know, but if it's more than 40km I'd be surprised,

challengemaster

Confab wrote: »

Impressive. Wonder what the range is like. Not the point of the car I know, but if it's more than 40km I'd be surprised,

In the link..

Rimac created a 900-horsepower beast that can hit 60 mph in 3.3 seconds, top out at 174 mph and – depending on how much he flexes his right foot – travel for over 100 miles on charge.

robtri

not the same but i know a guy here in ireland did an electric conversion to his BMW.....

jackbauer

Who's that then ?

Absurdum

he posts here IIRC

edit: lol just noticed yer sig :pac:

robtri

jackbauer wrote: »

Who's that then ?

ha ha brilliant...

yeah seen it up last year at energy show....
interesting project...
would love to do it.. mind me asking what was the cost to do it??

jackbauer

Cost about 8k in parts. Mind you a bit of that was taken up by bad component choices that then had to be changed out later such as the brake pump , lead acid batteries etc. The lithium cells make it a completly different car. My advice if you were to do a conversion is to use lithium. Last week nearing work i decided to try the old handbrake. Split second later the ass end is passing me out:eek: Not possible with 360kg of lead onboard:D

evbmw2 is starting in a few weeks . 328i convertible with a much more powerfull motor and autobox!

pajo1981

jackbauer wrote: »

Cost about 8k in parts. Mind you a bit of that was taken up by bad component choices that then had to be changed out later such as the brake pump , lead acid batteries etc. The lithium cells make it a completly different car. My advice if you were to do a conversion is to use lithium. Last week nearing work i decided to try the old handbrake. Split second later the ass end is passing me out:eek: Not possible with 360kg of lead onboard:D

evbmw2 is starting in a few weeks . 328i convertible with a much more powerfull motor and autobox!

What's the story with lithium polymer?

I've noticed these builds always use lithium ion rather than lithium polymer?

jackbauer

Lithium ion is a general name given to a lot of different types of cell cathode material. I'm using lithium iron phosphate (lifepo4). This has an energy density of approx 110wh/kg. Petrol has i think 1100wh/kg for comparison. Some lipo cells have up to 250wh/kg but the price is that its quite a volatile chemistry that does not tolerate under or overcharge. The big advantage of lifepo4 for diy ev conversions is that its quite "calm" and takes a lot of work to make it explode:D Lifepo4 cells are also readilly available in large format from a few ah up to 7000ah from china.

I think that some of the production evs we are supposed to start seeing this year use lithium cobalt or lithium manganese cells. These are a little better at approx 150wh/kg but require a lot or tender loving care.

Me ? i'd rather have 50 miles of range with a nice safe battery than 60 miles with rocket fuel!

RandomAccess

Your new project sounds neat.

Is it going to have all the batteries in the boot, or could you split them between front and rear to improve weight distribution?

Is it easier to build it with an automatic transmission?

jackbauer

Plan right now is to have 2/3 of the battery up front and 1/3 in place of the petrol tank under the back seat. I want to try and keep the car "normal" ie leave the boot as is. The automatic poses some problems the biggest of which is that a motor does not idle. So when stopped say at a traffic light the front pump in the trans goes down. this then causes the line pressure to drop and the clutch packs disengage. Now when i go to pull away the motor winds up like a banshee , line pressure shoots up , 1st gear clutch slams in and its wheel spin time:D

The simple answer is to idle the motor at a few hundred rpm to keep the pumps happy. Thats the approach i'm taking.

DublinDilbert

What sort of motor are you using in this one?

Do you have to feed the motor rpm, road speed and load to the electronics that control the transmission? So it knows when to shift etc...

How much did the li-battery pack cost and weigh? Did you assemble the pack yourself?

jackbauer

Motor is a kostov 11" hv 250v. Not sure about the gearbox as just getting started. It does have its own ecu so will probably end up interfacing to that.

lifepo4 pack cost approx 4k , weighs 95kg and yes i built it.

DublinDilbert

Is that a series or Ac motor? Not familiar with motor names.

I'm not sure how the info was sent between the engine ecu and transmission on e36 (e46 uses CAN). wiring diagrams would probably tell if it's a digital serial line or descrete signals.

jackbauer

Series DC with switchable fields. Similar to the one used in the e30 posted by the op but without the racing mods.