A progress report on EV Gearbox Magazine’s “in house” project truck, covering controllers, and some things looking forward in general.
Last time I talked a lot about batteries and range, this was a logical starting point as the choice of batteries due to my budget dictated heavy weight lead acid batteries, and the desired range (around 35-40 miles) pointed towards a larger pack, and therefor a truck.
I’d now like to look at controllers. There are a lot of factors that determine controller choice, but for me, and I’m sure for many of you, cost is going to be the deciding factor. First is system voltage. Controllers range from 24 volt all the way up to 300+ volt for some applications. My pack voltage will be 120v, and to move a truck from a dead stop with a normal pace , I think I need something that will pull 500 amps safely.
500a x 120v is 60kw This amount of power is only used for a fraction of accelerating time. 1st or 2nd gear, within the 3-4 second range, after that, the amp draw will fall off to below 200-150a. (60 kw is roughly 81 hp)
So, what are my choices ?
Top of the line:
http://www.cafeelectric.com/ – The Cafe Electric Zilla – high voltage 1000 and 2000 amp configurations. As I’ve said before in previous interviews with conversionists, this is the most coveted controller for any EV enthusiast. There is a waiting list, and they start at about $2,500 so for me it’s a bit of a stretch. I aim for this conversion to come in under $10k
Soliton 1 DC motor Controller – If you’ve got the money it is highly recommended, especially since it comes already with build in water cooling. – Between $2,900 and $3,200
Warp Drive controller – In the 72-200v 1000amp config this controller costs $1,900, so realistically it is still in the running, costing only $400 more than the Curtis. Also comes pre-piped for water cooling.
http://www.evalbum.com/dcp – DC Power Systems Raptor 600/1200 – These controllers are more Top of the line than most out there, I’ve heard good and bad. Unfortunately they are no longer made. I have seen a reconditioned unit for sale for $800.
http://www.cloudelectric.com/product_p/co-1231c-8601.htm – Curtis 1231C-8601 96-144vdc 500amp – around $1,500 new, and perhaps 8-900 used.
I’m pretty sure this is where my solution lies. It’s not too expensive, I’ve seen lots of conversions with them and I don’t have to build it myself (not keen on that ;) If I could get my hands on a pre-built version of Paul Home’s open source controller I would probably consider that over this one.
Specifically as Joe Yanoff mentioned, the Curtis does want to go into voltage cutback given our Arizona temperatures. For this reason, I will be adding active cooling, either Peltier devices or water block cooling, in addition to high power fans.
The advantage of this controller is also that it tops out at 144vdc, allowing for greater pack voltages will help if I ever manage to make the jump to lithium. Or a small scale arc reactor. ;)
(More on Curtis products here – http://www.curtisinstruments.com/index.cfm?fuseaction=ProductsGrid.Series)
http://www.cloudelectric.com/product_p/co-kdh12600b.htm – Kelly 24-120vdc 600 amp
If I can’t get a used Curtis, I will most likely end up with a brand new Kelly :)
By the way, for anyone looking for used EV parts like me here is an indispensable site – www.evtradinpost.com
Is slow. But its coming. I hope to have the engine removed by the end of January. The next step will be to replace the clutch and slave cylinder.
The radiator was junk, the overflow tank was full of oily sludge. The Exhaust system was barely attached and quite easy to remove :) I lucked out, no problem nuts. The bed is loose, but it has still yet to sprout legs and leave my garage.
Here’s what I hope my battery pack will look like:
Pictured are 16 batteries right behind the cab. I need 20, so I will add 4 in another row, or perhaps behind the rear axle, or in two smaller boxes either side of the drive shaft, under where some sort of bed will go. I don’t want any batteries (other than the accessory battery) under the hood. I’d like that area left as open as possible, so I can see the motor. The charger will most likely be under the hood also, more on that later ;)
EV Gearbox will be continuing into the new year and nurturing a database of interviews. Hopefully along the way I can help provide some sort of technical insight into building an EV with the interviews and also progress reports on the truck.
It’s been a great experience so far and I have learned a lot, I will continue the trend :)
As always I would be delighted to hear from any EV owners who want their conversion featured on the site. I admit I am not that good at searching for story leads, so if a conversionist emails me first it really helps ;)