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from lead to lithium

This section of the website is not intended to be a step-by-step documentary like I did for the Swift. This 'blog' is focused on what I did to upgrade a '94 Mazda MX5 (Miata) from a lead build to Lithium. The goal was to add a 'high-performance' EV to my garage so I could demonstrate the range of build options and cost to prospective clients seeking to rent, lease, or buy an EV conversion.

The original conversion of the vehicle was done by Henry Herndon in CA. He did a very nice job with reasonable high-performance components: Warp9 motor, Zilla 1k controller, Manzanita charger, Belktronix dc-dc, and a good job racking 144v worth of Optima Yellowtops. Henry also added some nice extras like a suspension upgrade and a heavy duty clutch to handle the added torque of the Warp9+Zilla. The batteries had predictably died after about 18 months of use, and Henry was headed off to Grad school and not wanting to put the money into a set of lithium batteries. I bought the vehicle hoping to be able to re-use almost everything and cut my labor time to almost nothing.

I intended to keep the motor, controller, dc-dc the same, recover a little capital by replacing the Manzanita charger with a less flexible Elcon, and hopefully make minor modifications to the battery racks to hold 156v worth of LiFePO4 cells. I wanted to go with 130ah-140ah cells so that I could pull the occasional 500amp or even 1000amp burst for high acceleration without killing the cells too fast. At the time, the 'new' CALB cells were not available, otherwise I think I would have stuck with the smaller and lighter 100ah cells! It will be nice to have the added range though for the people that live a little out of town. Unfortunately, the CALB 130ah cells are considerably taller than the old Optima Yellowtops, which forced me to re-design and re-fabricate the front battery rack and controller mounting location; adding a good 15 or 20 hours of labor I had hoped to avoid. The end result was well worth the time... a VERY fun and sharp looking performance EV, 200+HP, 60+ mile max range, and all for less than $20k in parts, batteries, and donor vehicle!

What's new...

This section I have decided to turn into a brief 'blog' noting significant milestones. There are more images in the Gallery of more of the details, click on the thumbnail image to jump to the appropriate section. Note that the most recent comment will go on top... 6/24/2013 - Odometer= 2950 miles - final pre-sales projects Wrapping up the last projects to prepare the Miata for Sale/Lease/Rent. Replaced the soft-top, Finishing up the carpet in the back. Replaced broken antenna with a 'shorty' amplified one... buffing things up for the car show on the 4th! I have been LOVING to drive this car daily, it's going to be hard to let go of it, but that's the reality of trying to do this as a business.     3/1/2013 - (new) Odometer= 725 miles - Official Re-Birthday for the Miata I'm going to consider March 1st as the Miata's official re-Birthday. Even though it was rolling at the end of December, I had it parked for a while trying to sort out the dc-dc issues, and then 3 weeks in the body shop. I'll be picking away at a few minor things, but its road worthy and ready for daily driving at this point.     12/28/2012 - 0 miles - ON THE ROAD !!!! Got down to MVD today.... re-titled, registered, inspected, licensed! Had fun explaining to clerk that I really wanted the registration to show '00 cylinders', which did flip the vehicle type to 'electric' in their database.... first one she had done. ;) So, its drivable.... VERY fun to drive as a matter of fact. I'll figure out how to run some performance numbers soon. Just have to tweak top balance a little bit, fabricate covers for the mid and rear batteries.... and a few small things before I would call it 'done'. One sizable project in particular would be adding a cabin heater. Henry had pulled all the ductwork and heater core in the original build, so it'll be a fair amount of work probably involving pulling the dash, which I dread in any car...   12/18/2012 - 0 miles - wheels are turning! Whoo Hoo! Wheels are turning! Turned the key, and everything worked! Just need some lids on the mid and rear battery cells, put the belly pan back on, and get this sucker on the road! ....and a little cleanup like a new rear window for the soft top, some carpet in the trunk, and figuring out what to do with the cracked leather seats (which can all wait till after its on the road!) A great xmas present to myself. ;)   12/12/2012 - 0 miles - Finished under the hood! Big milestone! Got everything 'done' in the motor bay... All components are in final positions and wired up, new rack bolted in, and battery cells are installed and cabled up. Just have a few hours labor left to rack and connect 12 cells behind passengers, and 12 more in the spare tire wheel well! Getting close to rolling...   12/1/2012 - 0 miles - Got controller radiator mounted, plumbed and grill re-installed. Motor bay is ready for batteries to get loaded into new battery rack now that controller cooler is mounted in grill, plumbed to controller, and grill is re-installed. Next is to fab lids for the front battery rack, which will double as hold-down for cells.     11/12/2012 - 0 miles - Got the front rack 'almost done'... needs lids still. Moving along at a slightly better pace.... got controller/contactor moved to firewall, re-fabbed hairball and vac pump mounts, and design/fabbed front battery rack and mounted dc-dc and new Elcon charger. Almost ready for batteries; just have to design/fab controller cooling system and put the front grill back together.     9/27/2012 - 0 miles - Got the lead out... Didn't get much time to work on it for the first month or so, but got enough time in to get the lead out, and brought it all down to the salvage yard! Became evident that old rack is just not quite gonna cut it with the 130ah cells, so will have to move things around a little and re-design/re-fabricate the front rack.     8/27/2012 - 0 miles - New batteries arrive... Batteries actually arrived on my birthday.... nice present to myself. ;) Now I can get them top-balanced, and use them to fabricate the battery boxes. Much easier to set up, clamp onto actual cells, and fabricate around them than to measure and attempt to jig square corners and such for this type of fabrication. It's going to be a challange fitting these 3 crates of batteries into the little Miata!     7/31/2012 - 0 miles - Miata arrives from CA. Still operational on the tired Optima yellowtops.... enough juice to make it up the driveway, charge, and drive around the block a couple times just for fun before pulling things apart.