Motor Controller Search

With this being a budget build, the motor controller has proven to be a bit harder to find than I had anticipated. I am trying to get one for a similar price as the motor, around $500-600. This has brought me all around the internet, and I have begun to realize I am going to have to get creative about this.

The issue comes in when many of the controller’s max amperages are taken into account. If you consider the equation kW = Max Voltage * Max Amps, this explains how voltage and amperage can be combined together to define the max kilowatt output of the controller. I am running a 144v system, and if my motor has a max output of ~150kW, then I need a controller capable of pushing around 1000 amps. And I would like to get something that can match those numbers, as this car is a bit heavier than the normal conversion. As such, this is where these items get expensive.

The controller I frequently came across is the Zilla 1k controller. This is a great controller with a ton of nice features for a DC motor like mine, but there’s a small problem. It starts around $2,000, or 4 times my budget. So that’s out of the question.

That leaves me with two real options right now. Either I can build my own, or try to reach out and see if anyone is willing to work with me to help with this project. I’ve found two potential results from both of these options, but I am not sure which to go with just yet. 

So it’s very much possible for me to build my own controller. I have some spare time here and there that could add up to be a sufficient number of hours to complete it. I don’t know if the cost will actually be better if I go this route though, as the controller that would be the best to built can end up costing $600-800 in parts. That isn’t saving me much, and I have to ensure I assemble it perfectly or else I’ll have to re-order things.

The other option I was given was a rebuilt EP-1000 motor controller. The deal is very good, about $500-600. This seems to be the better route, as it is a 1000 amp controller with a lifetime warranty. And it is built to work in conjunction with a motor like mine, so I know it will work together. This is definitely the option I am leaning towards, the only issue is funds at this point. Being a college student makes it a bit tough, and a bi-weekly paycheck ensures that saving can take a while.

The option of building my own is enticing because I can buy parts over time when I have funds, but the whole polished product feels like a better investment. So it looks like I am living on peanut butter and jelly sandwiches until I can save up for this, hope this all goes well!

About the author

Jameson Toper

I am a Computer Science Student at the Rochester Institute of Technology, and I have a strong passion towards the field of electric vehicles. When I am not working on this project, I teach a Computer Science course and make music.

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  • just found your blog.
    very seriously considering a BMW conversion myself.
    really appreciate you posting your experience here.
    keep it up!
    can’t wait to see how it comes out….

  • Great project! I have a sport motorcycle conversion under my belt and currently working on converting a 2003 e46 and a 2010 e90. Since you’re going the DC route check out Paul and Sabrina’s DC controller. Paul is active on the ecomodder forums I believe.

    • Those projects sound great! I’d love to see those cars you’re working on, those are going to make great conversions!
      I have checked out the schematics for the P&S controller and I have seen many people with great results, I am just not entirely sure if I trust myself to construct that from scratch. I’ve done circuitry and soldering, but nothing with this kind of power and importance. It’s controlling a motor that would be near to impossible to stop if it started getting full power, so the safety aspect is my real concern. I’ll definitely consider it and weigh the pros and cons.

  • Great Project!

    I’m starting my own in a couple of months. Similar to yours but my car is a bit heavier.

    Hope it goes well.


    • Thank you Peter! I hope some of my progress will help give you a bit of a guide on how to move forward with your own project. Which vehicle are you planning on using?

  • Hi, great reading.
    I’m just starting out myself, looking to do a DC conversion on a vintage car. I mean really vintage, like my -62 P1800, or a tiny -58 Opel if i can get my neighbor to part with it.
    I bougt a cheap series wound 80V dc motor from a forklift. I am also looking for a low budget option controller.
    Unfortunately, from what i’ve read, the EP-1000 controller seems to be a very low quality build and a bad option, even dangerous.
    You might want to do some more research into the ep-1000 if you are moving forward with it. I hope i’m wrong.

    Good luck!

    • I’ve heard some rumors of that too, I know one guy had his blow up on him. I believe I am going the homebrew route, it seems like Damien Maguire of has a real inexpensive IGBT controller that he is using in his cheap conversion. It’s just a matter of making sure I get all the right little chips and things for it and in a reasonable time frame.

      Let me know how progress goes on your own project!

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