Hey Electrified Miata (the eMiata name was already taken) team, here's where we are at.
Let me first paint the vision for the Electrified Miata. I want to build electrified miatas in various performance levels, all the way from pedestrian to face ripping. To that end, I purchased 2.5 Leaf motors. One Leaf motor weighs 126lbs and its inverter weighs 36lbs. Here's Kurtis and his EV grin helping weigh the beasts
I've also ordered 1000 LG MH1 18650 3200mAh 10A batteries.
Before we can run (or face rip) we must walk and before we walk we crawl (pedestrian). So, our first pedestrian task is to see if those Leaf motors run or not. An intermediate step to the Leaf's spinning is re-purposing our old electric go-kart as a test prototype.
Very lucky for us, someone has already figured out the magic required to make a Leaf motor go. Even spinning the motor is not as easy as it looks. First we need a power source of 140Volt DC at around 10 amps. Then a 12 volt source, which I have thanks to Korey and his motor cycle upgrades. We also need to be able to send and receive Controller Area Networks (CAN) messages to the inverter. We're at the point where everyone can help on this project.
The tasks in no particular order where help, advice, and/or experience would be greatly appreciated are:
1. Assemble two battery packs in a 20S20P configuration. That is 20 cells in series, each of those comprising of 20 cells in parallel. These packs will do double duty. They will be used on our electric go-kart for battery pack and Battery Management System (BMS) stress testing. The completed packs can also be put in series to power a Leaf motor.
2. The go-kart needs to be re-assembled and the Alltrax 7245 controller needs re-programmed to 72 volts.
3. The BMS will need some assembly. I've never done SMD (Surface Mount Devices), I could use some guidance on how to assemble and where is the best place to order circuit boards.
4. Separate the wire looms on the Leaf hardware to have just the inverter and the required motor resolver interface. Below is the current situation.
There is only one motor connection needed, although the inverter needs 12 volt power, battery mains, and CAN interface connections.
5. Develop hardware and software needed to communicate via CAN with the motor inverter. I have a few BeagleBone Black's and a few raspberry Pi's computers sitting around that should be capable of that with a little bit of extra hardware. I also have some python examples of CAN code. Getting that all working should do the trick, although I don't know what it means to acknowledge a CAN message so more research will be required.
Getting the Leaf motor to turn under software control - sounds pretty easy, right? No, not really, but I've found when multiple people get together, it becomes a whole lot easier and usually quite a bit of fun. Looking forward to meeting with everyone who is interested. Leave me a message with how to contact you and I'll let you know the details of when and where. If you aren't in the ATX area you and your expertise are welcome to join us virtually.
I'm so excited. I've searched the web and found a junk yard that had four motors, not one or two - FOUR! Even better, they were selling them for $510 a piece. This is going to be great. I can't wait! I looked at typical shipping prices and they look like they are going to charge approximately $250 per motor to ship them. I looked at the map and see a 1800 mile road trip. My truck gets 17 mpg and maybe more on the highway so about $200 in gas. Another $100 on hotels and maybe $100 on food. Approximately $400 seems better than $1000 in shipping fees. My son says he can go with me! This is awesome as I don't always get to spend as much time as I'd like with him. I called the junkyard 7 days before the trip (the longest I could reserve them for and I had to wait till my son was finished with his first college semester) and reserve the motors. Everything is good and I'll pay $2138 for all four of them. Can't wait and looking forward to the trip.
A few days go by and again I called the day before I leave to verify my motors are ready for pickup. This time, I got someone else on the phone who explained that I talked to a new guy and they only had two motors that have a 90 day guarantee and one motor that is damaged. Talk about a let down... Now my math on shipping savings doesn't look as good. I asked him to send me pictures of the damaged motor. Bad news, one of the water jacket outlet/inlets is damaged. I called him back, and re-negotiated the price. We settle on $1300.00 and I decide that having a few motors is better than having no motors. Besides, I get to take a road trip with my son who just finished his first semester of college. Score!
The trip is going to be 894 miles one way. We're planning on driving all the way in one day. Pick up the motors and drive back the next day. It's going to be some long days but we plan to switch off driving and that should make it somewhat bearable. My son and I start off around 4:30 in the morning headed to Carrolton Georgia. Cousin John T, and cousin-in-law John C, Bruce, Jeff Quick, truckers, I don't know how you guys do that day after day. We saw some nutty stuff where a car cuts off a truck (the lanes merge and the truck has no-where to go) and the car is beeping like crazy at the truck who was slowly moving over. I'm amazed we don't have more accidents with all that power, mass and driver rudeness. Yikes! Enough talking, what happened when y'all got there?
We got up early the next morning (eastern time zone) and had to heat the truck up because there was this crazy stuff called frost (We live in Texas where it rarely freezes) all over my poor truck. We show up right as the junkyard opened up and were first in line. I pay the agreed upon price and the lady tells me I have to a a VIN number to have a valid warranty. Wow, I think, I wonder if she'll take the VIN number from my Ford F150? So now I probably don't have much of a guarantee. I drove back to the junkyard warehouse to pick up my motors. We had to wait because there are company trucks being loaded with parts to go to local repair business. I walked in the warehouse to look at my motors. The first thing I noticed is there is no trans-axle attached. The pictures I'd seen on the web implied the engine assembly piece included the trans-axle so I kind of expected one to be attached. My fault for not verifying. Then I found that someone had tried (or succeeded) to take the top off one of the non-damaged motors! Now I'm getting unhappy and very unsure of what I'm paying for. My son probably didn't see the frown cross my face. The lady in the warehouse was paying attention when the fork truck driver picked
up the motor. She saw my frowns and let the fork truck driver to be careful with the connectors.
We loaded the motors up and they fit nicely 3 across in the bed of the pickup. We pull out out of the loading bay and my son and I re-strap the motors for traveling. My son did a great job with little guidance from me. I'm a very proud dad to have helped raised such a useful and helpful young man.
We set off to go 894 miles back from where we came from. Home sweet home.
My son had tunes on his phone and we played 'Sweet home Alabama' as soon was we crossed the state line into Alabama. We talked about when he first learned to play guitar (that was one of the first popular songs he learned). Around three in the afternoon and not quite 1/2 way there, my son and I decided we weren't going to be truck drivers for a living. We made it back safely and postponed unloading to the next day.
Unloading was definitely interesting, to say the least. The motors have lots of wires hanging out. Some of the connectors were smashed and it's obvious that the junkyard personal tried to separate the inverter, power delivery module and the motor, but they may not have been aware of the internal connections. As always, you get what you pay for, and these motors looked "used".
Let's look at the 12V connector. On motor 1, we have the stud where the 12 volt connects. On motor 2, the stud and connector are broke off. On motor 3, we have the entire connection intact. Overall, I'd say we have about 2.5 motors plus or minus a little bit.
The good news is all motors spin freely and feel about the same indicating no physical damage to the internals.
Wow, how are we going to turn this pile of junkyard stuff into a running electric car? Hah, that's a story for another day. Stay tuned for the adventures of E-Miata Team.
It's happening again... It has been a little over a year since I sold my Pantera and I'm getting the itch. The itch to drive something really high performance. The itch to drive something that can scare you if you take it just little too far. The Pantera was a so much fun, but I've felt that electric can do even better. Thanks to Kurtis Klein, driving a Tesla P100D confirmed it! I've been around just long enough to know I need to pay attention when I get an itch. In fact, while planning for 2020, I realized that a part of me would literally die if I didn't attempt this project. The part of me that tackles big bold audacious ideas. I fear getting old and dull. So, with the blessing of my wife, Teresa, I'm gonna scratch this itch! The real question for me is how to do this project, not break my bank and to still get performance that will beat my 500 foot/points (ft/lbs), 525 HorsePower(HP) Pantera. That's one tough problem. Enough talking, let's survey the current solutions and areas that appear to be problems.
Lucky for us, the internet has so much information available that the bottleneck is how fast I can read articles or view YouTube. I've spent a fair amount of time reading the postings on Do It Yourself Electric Vehicle forums. There are two areas where a lot of problems occur:
Surveying the motor/controller landscape here shows there are several routes to choose from, but none of them very cheap or easy. First there are AC and DC motors. When pushing parts to their performance limit, all the components need to be matched in strength and it's highly desirable to me to have no wearable parts, so and AC motor is a must. Looking at manufactured solutions, there aren't too many to choose from at this point. Here in the U.S., I've seen Tesla motors, Chevy Bolt motors and Nissan Leaf motor. Both the Tesla and Bolt motors are relatively expensive at $5-10K as a package (both motor and controller). If you choose 'off the shelf' varieties, say from evwest.com , the AC (and some DC) motors are $3K for 'go-kart' type motors to $10K for the really high performance motors. That's *without* a controller/inverter to drive them! Yikes. DC motors and controllers are a little better in terms of price (and low RPM torque) but you loose regenerative braking and have brushes which wear, especially if subjected to high levels of stress. I'm not a fan of maintenance if I can avoid it.
The reader who's been paying close attention will realize I skipped the Nissan Leaf. At first glance the Leaf motors seem too weak at 80 Kilowatts( KW)/ 100 HP. However, they do have about 250 ft/lbs of torque and they are relatively CHEAP at $500-$800 each. In recent news, Tesla has been turning decent lap times on a three motor solution for the model S. If three motors are good, isn't four better? I can buy four Leaf motors for less than price of 1 Tesla motor. Not only that, but there appears to be an upgrade path for the Leaf motors, as one enterprising soul is claiming 300 HP from a Leaf motor after replacing the stock controller and inverter.
The video of him spinning the tires at will, even after moving 30 mph on front wheel drive gives every appearance of a reasonable amount of torque and horsepower. So it looks like I can get started rather cheap on the motor/controller end by going with some Leaf motors and later change the inverter section to get the HP I want if 100 HP increments prove to be insufficient. I'm sure there are cooling issues with running 300% more power than stock, but that's a problem for down the road. Choosing the Leaf motor dictates using a 375 volt battery pack or closer to 500 volts to get some more horse power! Yikes, that means I better get some class 0 electrical gloves for the garage, cause I really *hate* getting shocked, not to mention all those volts can abruptly shorten my lifespan to zero. Lets talk about batteries.
Batteries are both very expensive and time consuming to put together, and somewhat dangerous if not treated with respect. To put some perspective on it, a small 30 mile round trip, uses roughly the same energy as my house does for 24 hours. That implies that a fully charged Electric Vehicle has a lot of power, similar to a gasoline tank. Treat that power with respect. Surveying the battery landscape looks like there are several key areas where I have some flexibility for design solutions.
As anyone who has completely restored/converted a car (electric or otherwise) knows, there is *so* much to do and I could use some help. If this seems to be be of interest to you, leave me a comment on the blog. I'm in the Cedar Park/North Austin Texas area.
OK, enough talking. Let's go get some Leaf motors. Four Leaf motors reserved, road-trip with my son! Will let you know how it goes.