Converting A Miata To All-electric

[Henry Herndon] converted a Mazda Miata to an all-electric vehicle. There’s a ton of great information in his archives, as well as a round-up video that we’ve embedded after the break. It’s interesting to see him implement two different types of Nalgene bottles as coolant reservoirs. The polycarbonate on the first shattered on him but the soft plastic replacement seems to have done the trick. The batteries add a lot of weight to the vehicle and he ends up refitting the suspension to compensate. [Henry] registered the vehicle with the state and now has a street legal EV of his own design.

Also worth a look is his post covering the 2009 Wayland Invitational. There as a large collection of electric vehicle conversions at the get together.


[Thanks Anthony]

23 thoughts on “Converting A Miata To All-electric

  1. neutral, so he actually is still using the transmission! hallelujah!

    I understand that having a single gear means less losses in efficiency, but it also limits speed, and makes sure there will be more noise at higher speeds. I’d much rather bolt an electric drive in place of the ICE, and leave the tranny as it is than have a great big huge tall gear that does everything.

  2. Very curious as to the BOM for the drivetrain/electrical. I am planning to build on of the AC Cobra “clones” and think this would be an awesome addition since I would need to buy the drivetrain anyway. No existing stuff to get in the way, and (at least in my feeble mind) I would chalk up the saved cost on not buying a combustion engine and trans as a “discount” to the electrical part.

    Also, I didn’t see in the blog, but is there an estimated range? How about speed?


  3. i competed in an Autocross race one time with a all electric miata running slicks and that thing was fast, but sorry i’ll take my turbo 2.0 sr20det over any motor any day boost gets you laid

  4. Is he using deep cycle lead acid batteries? Jeez, put a decent battery in there! Sure Lithium polymer might be too expensive for the project nature of this build, but you can at least find some decent NiMh cells that would double the range and give better acceleration for the same weight

  5. i looked at doing it with a split screen kombi…LiOns were the way to go and MASSIVELY expensive… even NiMH were out for as many as one would need…and lead acid??? land fill anyone… I estimated that it would be about $14,000 to do the kombi…take me 10yrs to make it back, right around the life cycle of the cells would be up

  6. FAKE.
    You can’t even hear the engine running!
    I think I would add some woofers that would output to the car’s exterior (wheel vents?) and make it sound like a growling V8. Or a jet engine. Anything to keep the vision-impaired informed.

    ooo ooo, the Jetson’s car! Yeah!

  7. That is cool but I bet he likes unicorns. I don’t care how well a Miata handles, he ruined it with all that weight. I live in Austin and hippies just kinda make me want to puke.

    Muuuuuuchhhh more into “hacking” on a turbo car that has no emission devices… and programming the ecu for maximum power.

  8. hmmph, so now it’s heavier (by a lot), has a very limited range, costs more money per mile than it would if it simply ran on gasoline when you take battery wear into account (he claims 20-30 miles/charge. Expect to see <200 cyclic charges on AGM cells – so if we shoot on the high-range side – that's only 6000 miles before the twelve ~$160/ea batteries are toast – a cost of $0.32/mile + electricity costs). Nooo thanks.

  9. Okay, then don’t build an electric car… Was it really that hard to think about?

    The craftsmanship and work done on this project vehicle is outstanding and that’s what matters the most. Hack your turbo car however you want, everyone else has done this. For what it’s worth Henry’s built a custom BMS for his batteries.
    Flashing different fuel/spark maps on EEPROM and playing with the wastegate? Yeah that’s pretty innovative there.

  10. For the doubters, if you’ve never driven an highway capable electric car, do so someday. You can test drive a Tesla Roadster at a showroom near you. The smooth, linear, seat-of-the-pants feel of electric torque is quite simply, addicting, and it will put a big grin on your face. Couple that with the exotic whine of the gears, motor, and controller, and it will get your pulse going in a different but entirely satisfying way. Once you experience that feeling, even a relatively short range becomes acceptable. I drove an electric Ford Ranger for a couple years. “Only” 70 miles range on a nice day, but I drove it to work 35 miles round trip every day, never had to waste my time at a gas station, and instead charged it at home while I made dinner. The gas car hardly got used except for long drives. It can work, people.

    Kudos to the author for doing a fun car.

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