-   Fossil Fuel Free (
-   -   Paul & Sabrina's Cheap EV Conversion (

MPaulHolmes 05-16-2008 02:32 AM

Paul & Sabrina's Cheap EV Conversion
5 Attachment(s)
OK, Gas is expensive. Don't get me wrong! I like choking on carbon monoxide as much as the next guy, but we have decided that it is time. My wife and I have been planning an EV conversion for the last several months. We don't have a dang car yet, though (lots of close calls, but we will have our car, by hook or by crook, by June 20th). We are hoping (settling?!) for 40mph top speed with horrendous acceleration. We are thinking of a Geo Metro.
We bought an $85 Curtis 300amp 48v controller on Ebay ($100 with shipping). I wouldn't have guessed that you could run a car on 48v, but there it was, bigger than life on youtube, the infamous Forkenswift... So, we will upgrade the controller later, but for now, this is fine.
We just bought a 6.7" GE DC Series wound 62 pound motor. It was $127. Not spectacularly cheap like if I bought a whole forklift and removed everything, but I live with my mother in law. She wouldn't go for having a forklift crushing the driveway.:eek:
We just bought an engine hoist for $100 (on sale) at Harbor Freight.
We picked up 8 6amp 12v chargers on sale for $20 each at Harbor Freight. The idea is later I will upgrade the controller to 84v, with a 12v auxiliary battery for running the electrical system of the car like lights and heat.

We bought a drill press at Harbor Freight on sale for $45. This will be used for making the adapter plate between the motor and the manual transmission bell housing. We will probably use 2 plates (thanks Lee Hart!). One attached to the motor face, and one attached to the bell housing. We'll probably use 0.25"x12"x14" (or so) steel plates. This will be explained in detail later. Spacers to be figured out later.
We got a whole bunch of 2 gauge welding cable with battery leads already attached. 12 battery cables that are about 12 inches each, and they all have battery attacher things (??) professionally attached already! 6 battery cables that are 7 feet long each with battery attacher things already attached. It was a very good ebay deal for all of them.
We bought a $2.99 volt meter from Harbor Freight, which will be used as a 0-400 amp ammeter (but the scale will be 0-200, oh well).
Today we bought a dual Curtis contactor/emergency disconnect switch rated at 72v (all in one object, hopefully this will also work for 48v?) on Ebay for a very good deal. It has a continuous current rating of 250 amps. It can handle 400 amps for several minutes at a time, good for later use too when we upgrade.
For a pre-charge resistor, I'm using 4 10 watt 10 Ohm resistors in parallel (for a grand total of 40watt, 2.5 Ohm.
Here's a few pictures of some of the stuff I'm talking about (plus my Ebike).
Attachment 738

Attachment 739

Attachment 740

Attachment 741

Attachment 742

dremd 05-16-2008 11:03 AM

Very very cool; I can't wait for further progress.

MetroMPG 05-16-2008 11:12 AM

Cool! Another one begins.

Comments: definitely keep your eyes open for the lightest host vehicle you can find, given your low power design specs. See posts #9,10 in the ForkenSwift thread:

I'm glad you're being realistic about the acceleration & top speed goals. Note that 40 mph may take half a mile to reach :) (on flat ground)

Are the chargers "smart" in any way? (Auto shutoff at a minimum?) 6 amps is going to be pretty slow to recharge a typical golf cart battery. Have you done the math?

MetroMPG 05-16-2008 11:14 AM

PS - you're in Seattle. Does that mean lots of hills??

MPaulHolmes 05-16-2008 02:53 PM

Lacey, Actually. I just said Seattle so people wouldn't say, "where's lacey!?" Almost no hills. I have my eye on a Ford Festiva. Hows that for tiny!?

MetroMPG 05-16-2008 03:45 PM

That's good news about the hills. (Or lack, thereof.)

Festiva sounds good. How much does it weigh? I think they may even be slightly less than the 89-94 Metro. Another consideration though: if you're going to add more batteries later, can it take them?

MetroMPG 05-16-2008 03:48 PM

Here it says 1797 lbs.

Here says 725 kg (1598 lb) - more likely, I think:

MPaulHolmes 05-16-2008 08:37 PM

The chargers are smart. It seems really slow to me too. I mean, If I'm using 2 115AH batteries in parallel, and 4 of those pairs in series, that's 230AH! Now, I'm no mathematician, but 230/6 = like 40 hours!!! holy cow. But I'll only be driving about 5 or 6 miles a day, so it should be able to recharge over night under those circumstances, and they'll last a long time, since each time I'll only use about 20-40% of the charge in the battery.

Good news. I was subbing in Autoshop today and the teacher came in at the last class of the day (not a single kid in there, since it was Senior Skip day). Well, there were 2 kids, but they "had to go get a drink of water". I think they forgot they were supposed to skip school that day. I told the teacher how my wife and I are working on converting a car to electric (once we get the car). He told me he could supply me with some extra parts if I needed them. I just need to let him know what type of car it will be.

Also found two 99 cent Lovejoy connectors that happen to be just the right size keyway for my motor. Oh, Rapture! Please don't outbid me anyone? Pretty please.

MPaulHolmes 05-18-2008 07:50 PM

Well, I've been hawking all my prized possessions on Ebay. I'm putting off my home-made motor controller until later. I had 4 cheap IGBTs, and have been selling them one at a time, so as not to flood the market. I got them for $12 each, and am selling them for about $30 each. hahaha! I'm so sneaky! I had most of my code written for the microcontroller that makes all the decisions on my controller. Coding is free, but unfortunately, it's also really easy, and the thrill is gone. That rabbit hole only goes like 3 feet deep. Anyone who wants a mostly finished program for a ATMega16 atmel microcontroller to be used in a DC motor controller, let me know. I'll sell it for $-5.00. That's right folks, I'll actually give you the program, and I'll give you $5. (A good application of negative integers! Well, I'll only give you the HEAVILY COMMENTED program). I'm just wasting time until 5pm EST. That's when part 2 comes on for CNN's "WE WERE WARNED!" HAHAHA

I have my eye on the prize, a $200 car by mid-June. It's going to be hard going 3 whole months without kicking any bad kids out of class. I watched CNN's "OUT OF OIL: WE WERE WARNED! Part 1" yesterday. I hope today's is better. What can we do? Ethanol? Hmm... Oh, I have an Idea! How about build an electric car! I hope they mention that option in part 2 tonight.

I was thinking of going to the store today to buy a few nuts that can screw onto the posts of the battery terminals from Costco. But deep in my heart, I know that's a waste of time. I can go there later to buy the nuts. I don't even have the batteries yet. I'll buy them at the last minute, since they don't like to sit on the shelf.

I went to a junkyard yesterday. They had 2 geo metros. Both were stripped to the bone. I just wanted to get a measurement of the spline thing that is inside of the clutch disk (with the springs in it). I found out that the transmission shaft has a bit of play to it. Like 1 mm or so. That's good. That means that making the adapter plate can have a hair of error in it.


SVOboy 05-18-2008 07:52 PM

There's a 300$ crx near my home in NJ, ever thought of one of them?

Looking forward to more progress, :)

All times are GMT -4. The time now is 10:54 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright