Category: Research

Battery Update

peter

Well, I got smart – I talked to the people that actually manufacture the motor and controller and asked their opinion.  I gave them the possible battery packs, and let them choose.  Turns out that there is a “no-mans land” that all but the high voltage pack would hit.  So I’m going to use the 349 volt pack (consisting of 109 batteries with 60 Amp-hours capability). Not cheap, as I was warned, and completely found out, but it should do the job admirably.

So, I await the billing and will get the controller updated at the factory.  Meanwhile, the minor stuff continues to get cleaned up.

Battery decision time

peter

I went and did some initial testing on the 12 volt system in the car, and it doesn’t have any obvious shorts, so it is ready for testing.

However.  A number of disturbing reports on how badly the car will perform with 1200 pounds of lead acid battery has me very worried.  I’ve read several real-world scenarios of max 50 miles and very weak acceleration.  Since I need need to have freeway speed and the ability to climb some steep hills, this is just not acceptable.

The only solution is to go for a higher voltage battery pack, and lead acid batteries won’t do it.

Time for Lithium.  Lithium Iron Phosphate.  Trouble is, that these are only made in China right now.  And they are expensive.

Comparison time (shipping not included):

  • Lead acid pack, 144 volt, 12.9 kw, $2600.
  • Lithium pack, 163 volt, 13.7 kw, $8000.
  • Lithium pack, 243 volt, 20.4 kw, $12,000.

That last pack will take up the same space as the lead acid batteries, but provide much more voltage and almost twice the available capacity.  The cost is just astounding though.

I’ll keep you posted on any further thoughts on this.

Conversion Kit

peter

The kit I’ll be using for this project is available from Electro Automotive. It contains an AC motor, controller, battery racks, cables, and heavy-duty suspension. This is a bit lazy on my part, but I wanted to have most of the guesswork out of the way on this first project.

What’s interesting (to me) is that it requires the use of old-school 8 volt batteries. The kind that requires constant topping off with water. I asked why not use the newer sealed batteries, and the reply was, “You could, but you would get greatly reduced range and amperage.” Good enough.

Some other projects are looking into state-of-the-art (i.e. ultra expensive) lithium-phosphate batteries. These don’t explode, unlike lithium-ion batteries. They also cost around $2000 per battery. Ummm….don’t think I’ll go that route any time soon.

I ordered the kit on July 10 (mailed the check), so I can expect the kit to arrive within the next two months. The long lead time is due to the fabbing of the battery boxes. The motor and controller will drop-ship from Azure Dynamics. The other parts will ship from Felton to me as they become available.

Cheers!

Starting……now!

peter

Hi Folks,

I just bought a 1975 1.8 liter Porsche 914. It is sunflower yellow, and in pretty good shape. A few spots with rust (although I’m sure I’ll find more later). The transmission needs to be rebuilt (big surprise, eh?) and the engine has a bad case of vapor lock.

Having had the car for a few days, I figured I would start by taking out the old-n-busted alarm system. Easy, I thought. Until I tried to remove the wires leading into the cabin. Um. Ok, so how do I remove that panel from the back of the cabin? Time for the manual (again).

More later!

Cheers, Peter

P.S.  Some photos for you:

Left rear view of the original car

Left front view of the original car