[NycEV]

Hi there,

Here's a summary of what I have planned:

Vehicle: 1994 Mazda RX7
Motor: HPEVS AC-51
Controller: Curtis 1239e-8521
System Voltage: 144 volts
Batteries: CALB LiFePO4
Transmission: Yes - TBD
Charger: TBD
DC/DC Converter: TBD

I've had the RX7 for a while now. Back in 2012 it was street prepped and converted to run a small block chevy. I drove it twice before blowing the tranny. Since then it sat indoors. A few weeks ago in July we pulled the engine and tranny and then in August I scored a used HPEVS AC51 motor & Curtis 1239e-8521 controller. Since then I've been reading up and planning the rest of the build. I haven't purchased the batteries yet but I like the LiFePO4 chemistry for ease of use, safety and forgiveness.

I can wrench but I'm a software guy and not particularly knowledgeable about electricity, wiring etc. Everything I know I've learned for this project.

Here are some links that have helped me along the way for other newbies to check out:

1.) Calculating Battery Pack Size

https://www.youtube.com/watch?v=uLrCFStQQUU

2.) True Cost of Converting

https://www.youtube.com/watch?v=lEQoKTjsRMo

3.) Selecting a motor and controller:

https://www.youtube.com/watch?v=iqRdBtzv88c

4.) Here's a build schematic from EV West that I was stoked to find:

I'll post some pics later.

 

[brian_]

I'm looking forward to following the build.

I find it extremely tedious to watch and listen to hours of amateur videos, hoping for a few bits of real information... can you share with us a brief summary of the results for your conversion, such as the number and capacity of cells? Also, it looks like there was supposed to be a link to EV West's schematic but there isn't one.

 

[bawfuls]

I find it extremely tedious to watch and listen to hours of amateur videos

Richard's videos at EV4U are definitely slow and tedious, yet they also manage to leave out tons of details I'd like to see. I have watched a lot of his to get info on my build though, typically I set the speed to 1.5x on youtube and just pause/rewatch key bits.

I wish there were more people doing EV conversions. The quality of build videos on youtube is noticeably lacking compared to what you can find with normal ICE car builds.

 

[NycEV]

I appreciate Richard's videos. There's a lot of new stuff to learn when moving from ICE to diy EV. To be fair it took me a while to learn the ICE stuff too.

For noobs:

The video about selecting a motor and a controller explains how important a decision that is for the rest of the build as well as what it means on the AC vs DC side of that choice. Bottom line for an AC motor you typically have to use the matching controller. For a DC motor there are more controller choices.

True cost of converting breaks down the all in costs which is an important thing to be clear on when you start a build. Richard's experience is valuable there too.

Calculating battery pack size breaks down step by step how to calculate range and battery pack size. I think that's the most important video for me now. I still haven't decided on the 100ah or 180ah cells yet so I need to run through the calculations and costs again on that one.


In the meantime let's get to some engine pull pics! I don't feel like there's a lot to show on the EV side yet. It's just the motor and the controller. Not much to look at.

The exhaust is out. I started sizing up the gas tank and will need to get at that. I'm also thinking about where I want to put the batteries. The Zeva build puts some of the batteries in the "boot" by cutting the spare tire wheel well and recessing a battery box but I'd like to avoid cutting if possible (realize that may not be avoidable). I also would like to avoid that in order to not change the handling of the car. Be we will see.

 

[NycEV]

Also for noobs - The AC vs DC question. I probably would have gone DC if I didn't score the used AC system. DC is just cheaper. But AC has some benefits I liked in terms of regen braking, no brushes to maintain (which really isn't that big of a deal from what I've read), idle, ease of install and AC just feels more modern.

I think that's it for the noob section. I'm open to any other nooby questions out there. PM me instead of a thread hijack. It took a lot of reading and research for me to get my noob questions answered. If I can save somebody that time just hit me up. In my mind there's some way to make all of this easier for noobs but maybe that's wrong and it's all part of paying dues.

 

[brian_]

Also, it looks like there was supposed to be a link to EV West's schematic but there isn't one.

4.) Here's a build schematic from EV West that I was stoked to find...

Thanks for adding the link

 

[Emyr]

I have watched a lot of his to get info on my build though, typically I set the speed to 1.5x on youtube and just pause/rewatch key bits.

I'd like to confess that I always watch Damien at 1.25x, but 1.5x is a little too fast.

 

[MattsAwesomeStuff]

I'd like to confess that I always watch Damien at 1.25x, but 1.5x is a little too fast.

2x, and when he's recording video late at night without any sleep, I wish there was 3x.

Damien doesn't run off a script. He barely runs on bullet points. And by the time he's recording for us, he's at the end of a long day. He's at the point that most of the rest of us would call it quits and not document what they've done. But he does it anyway. I generally find that anyone running on a tight script is good for 1x. Anyone with prepared topics is 1.5x. Anyone having to think about how they want to say what they're saying, I'm good for 2x.

It's harder to come up with a way to convey a thought than it is to absorb that thought.

Also, I started saying "trottle" out loud the first couple times he said it, and now it's compulsive. "So I'll connect the trottle".. "Trottle!"...

Then there's EVTV, which, even 10x wouldn't be fast enough and I never watch.

 

[NycEV]

2x, and when he's recording video late at night without any sleep, I wish there was 3x.

...

Then there's EVTV, which, even 10x wouldn't be fast enough and I never watch.

Lol - I've come to value accuracy over speed. Especially as a beginner. Watching Damien/EVTV I just bit the bullet and dealt with the slow speeds. Damien was a huge inspiration too.

 

[NycEV]

I'm back on the case now that the weather is better. My kids helped me strip the interior, dash, etc and dump the old carpet. I bought a Can EV adapter from a member here. I'm going to get an RX8 tranny next. I need to run some calculations on the Leaf vs Volt batteries to power the 144 volt system I'm building. After that I have to mockup where the batteries will go.

I also need to tackle pulling the gas tank next - I'm most of the way there on that.

I really don't want to cut the trunk to fit batteries in the back. Any reason why I have to? I believe there are safety regulations about isolating and lowering the battery pack. I need to research that next in order to make a final decision.

I had a few moments of weakness and almost turned back to ICE because I was worried about the performance (speed) of my build with my components. At this point I'm all in. If I'm not happy with the performance I can always upgrade later.

Pics

 

[EVmattyP]

You sure you want to use an AC51 motor in an FD3S? From what I saw the AC-51 will only make 88hp and 108tq MAX. Also, depending on your pack size you're probably not going to be saving too much weight.

 

[[email protected]]

any new updates on this build?
newbie to this forum
love RX7 FD(been track racing them for 16 years)
also have a FB1985 and a 2011 RX8

looking for a donor RX or miata now to do a EV convertion

 

[NycEV]

Yep I'm still on it. I've owned this car since 2009. Looking at the Tesla powertrain now.

 

[NycEV]

This build is back on. I was tempted to switch powertrains but given this is my first build -- sticking with the AC51 which is tried and true, and then upgrading to the AC35x2 later repurposing the 1239e controller sticking with 144v -- is more achievable. Plus I got a great deal on a used AC51 and 1239e to begin with. Now I think the last agonizing decision is the batteries. I was set on Tesla batteries with the Orion 2 BMS thanks to this video but then I like how forgiving the LiFePO4 chemistry is. Then I read this thread and think I need to look again (5th time) at Leaf and Volt batteries.

So right now I just got a used RX8 tranny, the controller harness, and a few other bits on top of what I already have so I can bench test the drivetrain. Then I want to tackle the magic number and drivetrain fitment and battery placement. I need to finally get this car roughed out and moving.