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Vardom 08-06-2013 05:29 PM

Wanting to Start an EV Project
Hey guys!

So I want to start an EV Conversion project but I've ran into one tiny little problem. No offense to all of you EV conversion pros but I haven't been able to find a very thorough "laundry" list of what is needed and a how-to.

I would be more than happy to do this myself but I would like to ask a few questions for all of you Backyard EV guys :)

1) What is the full laundry list of parts that I need?

I realize that this may be different based upon the car. But it will most likely be related to ForkenSwift.

Things I know I'll need:

~Motor Controller
~DC Converter
~Charging System
~Wires (I've read #00 Welding cable???)

Oh yea... And I think I'm missing something.... oh yea an electric motor!

Anywho, I would greatly appreciate any and all tips that you guys could give me!

Oh and one last question that I forgot to add! I have a question from the beer budget EVs. How much would you estimate your EV build would have been if you were charged $25 a battery?

mechman600 08-06-2013 05:45 PM we go. First off, you will not regret building a beer budget EV. No matter what anyone says, GO FOR IT! It's a lot of fun.

In your "Things I know I'll need" list you can do without the DC-DC converter. For any converter with the output you require (I say 40A mininum @ 13.8V), you will pay hundreds of dollars. I went with a group 31 truck battery (free) and a $20 PWM trickle charger (puts out 2.2A).

Battery cables can also be free. Make friends with a commercial truck salvage yard. They all use 4/0 cable. With a low budget EV you are likely going to be at 72V, so amps will be a bit higher than normal. Big cable is good for higher amps.

My Alltrax AXE7245 (72V/450A) controller was $300 used on eBay. It has been absolutely stellar. I have never experienced thermal cutback in my 3000 lb lead sled, and that says a lot.

Go with a forklift motor, if you can find one. Here is an EXCELLENT guide:
Using a forklift motor, and choosing a good one - DIY Electric Car Forums

Don't forget:
-A bunch of 1"X1" angle iron, 1"X1" and 1/2"X1/2" square tubing for battery racks.
-40-50 4/0 copper cable ends
-Various nuts and bolts
-Chunk of 1/2" aluminum for adapter plate
-A piece of 5/8" particle board from the Ikea "as is" section for a control system mount. (This is my top secret item....shhhhh..don't tell anyone). You can mount ANYTHING to it (controller, contacter, etc with a couple of particle board screws.
-Lots of butt connectors, ring terminals, heat shrink, 18 gauge wire.
-Potbox. $60 for the PB-6 @
-vacuum pump. A used Volvo pump from a junk yard/eBay + a $25 vac switch.

I will probably think of more.....
Good luck!

cRiPpLe_rOoStEr 08-06-2013 06:38 PM

EVs are not my speciality, but I'll be looking at your project and eventually I can give you some help. BTW which is the base model for your EV conversion project?

Vardom 08-06-2013 11:58 PM

Well... so far the only things that I have found withina reasonable price in my area would be a forken... sorry, a Geo Metro (I have one but it would not work since the body is bent and rubbing the shocks. Even if I straighten it, I wouldn't want to risk the durability of the body with the load of batteries.) and a 1980 Trecel.

Mechman, I actually read your entire thread on your journey to your eMX-3. The part in particular that I would love to hear your opinion on is the batteries. I know that you ended up switching to AGMs because your "surplus" was just badtruck batteries xD.

The question I have is this:

My uncle owns a dealership in town. I ran into him the other day and told him about my idea and he told me that he would sell me the batteries at cost ($25!). Mind you, I don't know the exact rammifications of this (the are "reconditioned" with a garauntee that they are in working condition with "several" years left on them, haha... not with an EV in mind ;)). I figured that I probably wouldn't have as much power and possibly less range. The idea though is to get this started, then the money that I would normally put towards gas goes towards electricity, and the left over into a "buy awesome batteries" piggy bank.

Ideally, I would love to get a 50 mile range of speeds upwards to 55-60mph ( I would almost never go that fast, it's simply if I HAVE to go on the freeway for some odd reason, like road closures, etc.) so a range of 50 miles at around 37 mph average (speed zones here are 40mph -a good portion- 35mph -a majority - 20mph -short duration- and 45 - not even a quarter mile, I would probably just go 35 in this area anyways)


Speeds up to 35mph
Range: 30 miles
eMPG: 60+ (My geo even in it's dead condition and no mods/driving techniques is at 38mpg)
Safety! (who needs that!)

Would like (ultimately):

Speeds up to 65 MAX cruising speed. (Simply to show off to friends and family. Practicality, 60mph)

Range: ∞ (just kidding! But seriously that would be a nerdgasm!) 50+

eMPG: 100+
Safety ( Again, what?!)
Luxury!!! (Heater/ cushy seats / nice custom interior / sweet paint job!)

Okay, with luxury, I'm sure I could get the heater, MAYBE seats, and I've got a buddy that does custom paint jobs! (maybe could show up in springfield/eugene area on another EV!) Interior... Well I always wanted to try my hand at wood working but I think it would be best if I went with an ultralight plastic or fiber.

Anywho, if you are thinking that my eyes are a bit bigger than my stomach... Probably :P

oil pan 4 08-07-2013 03:54 AM

Build a gen set trailer so you can have unlimited range when you need it.

Ryland 08-07-2013 09:04 AM


Originally Posted by oil pan 4 (Post 383919)
Build a gen set trailer so you can have unlimited range when you need it.

what size gen set are you using on your EV and how much did you spend on it?

mechman600 08-07-2013 07:40 PM

Gen set trailers are beyond the realm of beer budget. The massive charger to make this work puts it way over the top.

Vardom 08-08-2013 04:21 AM

It is still good information to have.

Let me put my "plan" for an EV conversion down so you guys understand where my line of thinking is.

I intend to do the conversion on a beer budget. A mix of looking for a used sit-behind electric forklift (so I can scrap that baby afterwards!), and perusing craigslist. I've found some interesting electric motors in my area for under $200 but I know little to nothing about EMs so I haven't really jumped at them.

Howard 2 hp electric motor

5hp 3 phase electric motor (most appealing to me so far)

Anyways, original plan is to get a forklift, get the needed parts, scrap the lift. This will be either before or after I choose and buy the donor car for the conversion depending on if I can find one of the other for a great price. I have a hook-up for batteries (my uncle owns a dealership and will sell to me at cost of a whopping $25/battery!).

The electric rates in my area are $0.0514/kwH and basing the next bit of information off of the eBooger, that would mean a total increase to ~$107.38, which would still be about $130 cheaper than my current gas-gussling car. That includes the PEAK of my electric usage during winter (never above $35, including the $9 delivery charge.)

What I would do with that extra $130, save 1/2 of it to invest, the other 1/2 into an "EV Upgrade" account which would get me nice things such as new batteries, upgraded motors, better controllers, better chargers, better etc. xD

So I am starting off with a beer budget but the end goal is the sky.

MetroMPG 08-09-2013 11:05 AM

Don't want to rain on your parade (agree with Mechman - it's a fun project - dive in!), but you need to manage your expectations.

I predict you're going to have a very hard time getting the range you want from the batteries you're being offered. To start, you're going to need to know the rated & actual (tested) capacity of the batteries you have access to.

My buddy & I paid scrap rate for the used golf cart 220Ah batteries in the ForkenSwift, and the best range they ever provided (about 3 years ago) was 35-40 km (20-25 mi) when driven extremely conservatively in ideal, warm weather, at a low average speed, probably below 40 km/h (25 mph).

With ForkenSwift, we would have been satisfied with a real world working range of 16 km. That's essentially a trip across town & back again. :D

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