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Discussion Starter · #1 ·
My wife says that I should start a new project to keep me sane during this pandemic since I'm no longer racing with my track car or UTV. My initial desire was to buy a forthcoming z06 C8 corvette but considering I work from home now and am no longer driving much farther than to pick up my son from school, she thinks I won't find nearly as much enjoyment out of just "having" this car than building a new one.

Being in California, my choices are traditional engine swap using a 50-state legal crate (the e-rod LS swap @ $12-15K) into a 95 or older donor or something cheaper into a pre-1974 chassis. At the end of the day though, I'll end up with a car that if it takes me a while to build (call it a few years), I expect I will only have a few years (IMO <10 yrs) to enjoy it while a) gas is affordable and b) California starts cracking down further on gas-powered vehicles.

This has led me to consider an "interesting" car, with a timeless look, and doing an EV conversion on it.
This isn't something to build and then resell later; I would want to keep it for the rest of my life and fortunately, I have the garage space (even in SF) to do so.

Anyway, my wifes only stipulation is that she wants a car that seats 4. My son is only 6 so even a 911 sized back seat will be sufficient.
  • Use-Case is not as a DD (I have an appliance - a white Prius - for that) but as a car to enjoy on weekends and for other errands. I don't mind having the car in pieces for an extended period of time as I find THAT more enjoyable vs just writing checks and having someone else do the swap for me.
  • Given the budget, I want a donor will all the trim/minor switch bits in the $20-$60K. Having the car running would be a plus because I don't mind enjoying the car as an gas powered vehicle while I fix up the other systems which will likely need work (suspension/brakes).
  • My expectation is that the Tesla DU based EV kit (like the one sold by electricgt.com) will run me ~$40-42K. I'm OK with that even though I recognize I could buy a whole poverty spec Tesla for that price (which I don't want). Based on my research, it seems to be a fairly "straight forward" swap with the hardest custom parts will be building your own battery box and the LDU mount bracketry.
  • I want something nimble which means decent handling with a preference for the engine being in the middle (never had one).
  • I'm not afraid of tearing apart a car and replacing/upgrading whole systems with that. I've done that with my lemons track car (V6 -> V8, automatic -> manual, complete car harness stripping/rebuild, brake/caliper upgrade, DIY suspension using parts meant for another car, and tweaking the ECU firmware using Moates quarterhorse).

I have one 70s exotic in mine but am open to suggestions.
  • I did consider the volvo amazon but the trim bits/parts availability worries me. I'm also not 100% sure handling will be great and I suspect I'll have to spend a lot of time dealing with that.
  • The BMW 2002tii is another option (wife likes the timeless greenhouse) but Id like the engine in the middle.
  • Finally, the 911/912 variants seem like a good mix of parts and EV KIT availability but they don't speak to me (capable car but there are plenty around).

Anyway, I'm also interested in feedback on the ElectricGT kit.
It seems like it has all the parts I need and the AEM VC software has a lot of control functions I would need to tune the car for driveability -- not everything is lived a 1/4mi a time at WOT
I see that its their own battery modules using LGChem pouches but I need to do more research on them.
Q: Are there other EV kits I should consider?
 

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Your wife is a wise woman. Idle hands being the devil's plaything and all that. Nice to be encouraged to spend less time around her :p.

"Kits" aren't really kits, with how much everything needs to be customized. Shops, if they have kits, often specialize if a very narrow set of donor vehicles to have any chance of compatability.

If you're looking at a several-year long project, I wouldn't buy a kit. You clearly have the budget for toys, but I don't know that it would provide you much value, especially as someone who enjoys tinkering anyway. DIY EV is changing fairly rapidly. The meta of your build will be obsolete before you're done.

Your component selection can be almost completely agnostic. A motor just needs a power signal to spin, that signal can come from any (suitably configured) motor controller. The controller just needs battery in a general range, and it can be any battery. All your little supplementary components can be whatever.

The current DIY meta is seeing a lot of development towards VCUs, vehicle control units, off of a common base infrastructure. A touchscreen and visuals and integrated CAN and all that. These are rather nascent at the moment, proof of concept, but by the time you're done they'll be much better fleshed out. There's also a current microchip shortage that'll bleed into the next year, so I wouldn't be too keen on choosing any particular solution just yet.

Buy your batteries next to last, until then keep an eye on what you're likely to choose and how much space you have to put them. They're big, heavy, cheaper-the-more-you-wait, and better-the-more-you-wait.

90% of your enjoyment from the vehicle is going to be in your selection of the original vehicle, especially because you've got the budget to get what you want, so, I'd spend a lot of time playing there. Pick something older, the newer something is the more struggle there'll be disabling and fooling it to just being a normal car.

You could pick a motor now, or a motor target. Motors are going to be just about brainless. If you know what kind of performance you want, that'll help guide what you pick and how you're going to start integrating it into the car.
 

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Discussion Starter · #3 ·
Thanks Matt. I may in fact go the piecemeal route but one of the reasons I might lean towards a kit (that's basically a pile of parts vs a turnkey pile of parts + every cable+hose cut to the right length and prefab):
1) by writing one company a decent enough check, I would hope that I would get some amount of technical support. I'm just now learning about EV conversions and all the componentry necessary to make it work. Even now, looking at a build from 2014 I can see that some things you'd do back then you wouldn't necessary do 6 years later (ex: I like the idea of keeping a stock transmission but the reality is that if the build requires a flipped and shortened G50 porsche transmission @ $15Kish ($8K + mods) + custom bellhousing adapter when the alternative is just use a Tesla LDU in F/N/R, I'm going the Tesla route.

It definitely seems that mounting the motor and fabbing up your own bracketry is the first key to this project. I have some ideas on how to tackle this project.
Q: If I did NOT go the Tesla LDU path, what are the common motors to consider to mate to stock transmissions with adapter plates for something like a BMW2002? From looking at various kits it seems like the AC51 or AC34x2 seem like popular choices. I guess it will be interesting to see if Ford/Chevrolet are able to compete with suitable motor+controller+charger combinations (it seems that the ford solution is a motor without a controller)

2) I'm not excited about making my own battery modules. I know this isn't a today or tomorrow problem but I know my limits. I can build a box. it might not be perfect with gorgeous tig welds like a row of dimes but it will work. I'm NOT excited though about making my own modules or designing + milling out my own chill plates. I'd much rather throw money at this part of the problem and get something that can drop right into a box.

Q: Are the OxDrive OXDP modules any good? This is clearly not something I would buy tomorrow but I'm curious where they fit in the ecosystem

3) It also keeps that the High voltage junction boxes are something else I'd rather buy off the shelf vs fabricate myself.
Any opinion on this design (I suspect the plugs are optimized for the packages they sell)
 

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Hi
I built my car using a forklift motor
If I was doing it today I would be using the parts from a production EV

Its not so much the motor that you use as the complete power unit - motor, reduction drive and dif

Treat that as a single unit

Batteries
Batteries split easily into "modules"
Modules are very hard to split into "cells"

Treat a battery "module" as your building block

The BMW 2002 would be a great choice - a very light body shell
 

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Q: If I did NOT go the Tesla LDU path, what are the common motors to consider to mate to stock transmissions with adapter plates for something like a BMW2002?
Non-problem. Just drop both off at a machine shop and say "connect these two together", and they'll do it for you. Probably run you $1000. Perfectly custom, anything you want. You'll pay more than that for the "kit" one, and be confined to their choices anyways.

All the savings of mass producing an adapter plate are swallowed in the markup of the company selling you the kit, which only limits your options.

For a machine shop, this request is like a 1/10 for difficulty. I wouldn't consider it a design constraint in any way. Do what you want, throw a little green at it, and the coupler and adapter plate is solved.
 

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Thanks Matt. I may in fact go the piecemeal route but one of the reasons I might lean towards a kit (that's basically a pile of parts vs a turnkey pile of parts + every cable+hose cut to the right length and prefab):
1) by writing one company a decent enough check, I would hope that I would get some amount of technical support. I'm just now learning about EV conversions and all the componentry necessary to make it work. Even now, looking at a build from 2014 I can see that some things you'd do back then you wouldn't necessary do 6 years later (ex: I like the idea of keeping a stock transmission but the reality is that if the build requires a flipped and shortened G50 porsche transmission @ $15Kish ($8K + mods) + custom bellhousing adapter when the alternative is just use a Tesla LDU in F/N/R, I'm going the Tesla route.

It definitely seems that mounting the motor and fabbing up your own bracketry is the first key to this project. I have some ideas on how to tackle this project.
Q: If I did NOT go the Tesla LDU path, what are the common motors to consider to mate to stock transmissions with adapter plates for something like a BMW2002? From looking at various kits it seems like the AC51 or AC34x2 seem like popular choices. I guess it will be interesting to see if Ford/Chevrolet are able to compete with suitable motor+controller+charger combinations (it seems that the ford solution is a motor without a controller)

2) I'm not excited about making my own battery modules. I know this isn't a today or tomorrow problem but I know my limits. I can build a box. it might not be perfect with gorgeous tig welds like a row of dimes but it will work. I'm NOT excited though about making my own modules or designing + milling out my own chill plates. I'd much rather throw money at this part of the problem and get something that can drop right into a box.

Q: Are the OxDrive OXDP modules any good? This is clearly not something I would buy tomorrow but I'm curious where they fit in the ecosystem

3) It also keeps that the High voltage junction boxes are something else I'd rather buy off the shelf vs fabricate myself.
Any opinion on this design (I suspect the plugs are optimized for the packages they sell)
The OXdrive modules are decent, but very expensive and you need to design your own heating/cooling system.

Tesla modules are the way to go. High energy density, integrated coolant loop, and reasonably priced. Each cell is also fused for safety. That's not something that can be easily replicated in a DIY module.
 

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Tesla modules are the way to go. High energy density, integrated coolant loop, and reasonably priced. Each cell is also fused for safety. That's not something that can be easily replicated in a DIY module.
There is no need to fuse each cell in large-format cells, which typically have only two or three cells in parallel. This is only required when using the tiny cylindrical cells, and thus having dozens of cells in parallel. The fuses are just the fine wires which connect each cell to the bus plates... but attaching those wires is an issue for DIY construction.
 

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Discussion Starter · #9 ·
The OXdrive modules are decent, but very expensive and you need to design your own heating/cooling system.

Tesla modules are the way to go. High energy density, integrated coolant loop, and reasonably priced. Each cell is also fused for safety. That's not something that can be easily replicated in a DIY module.
I understand the value that the tesla modules provide. I need to research this component more but realistically, step 1 is to find the right donor car for my project first before I go too far down that rathole.

After that: I know the car I want can fit the Tesla LDU between its rear frame rails so buying a car, upgrading/refreshing the brakes/suspension/steering on the vehicle, fabricating the bracketry to mount the LDU to drive the rear wheels are higher priority than the battery box stuff.

The battery stuff is a bit academic now. Since its an interesting enough topic though

Q: Don't most people who buy tesla modules have to replace the BMS system from OEM to a 3rd party module?
Therefore, in the process of building your battery box it seems to me that you buy the tesla battery pack, you replace the OEM BMS PCB with your own, and then wire it in alongside the cooling paths and the drive current cables.

With the OXDP setup, it seems that you buy the modules and they have chill plates through which you would route the cooling system. It seems that OXDP also specs in the AEM BMS system which uses CAN-based modules that allow the head BMS unit to talk to each of the module boxes. I need to dig into this further but at face value, this seems pretty straightforward to use.

One area of concern for me is that while the OXDP battery modules seem to be based on the LG Chem pouch cells.
Q: Aren't these the same cells which are having issues with Bolts catching on fire? I have a friend who's Bolt seems to be in the process of being bought back/replaced.
 

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I understand the value that the tesla modules provide. I need to research this component more but realistically, step 1 is to find the right donor car for my project first before I go too far down that rathole.

After that: I know the car I want can fit the Tesla LDU between its rear frame rails so buying a car, upgrading/refreshing the brakes/suspension/steering on the vehicle, fabricating the bracketry to mount the LDU to drive the rear wheels are higher priority than the battery box stuff.

The battery stuff is a bit academic now. Since its an interesting enough topic though

Q: Don't most people who buy tesla modules have to replace the BMS system from OEM to a 3rd party module?
Therefore, in the process of building your battery box it seems to me that you buy the tesla battery pack, you replace the OEM BMS PCB with your own, and then wire it in alongside the cooling paths and the drive current cables.

With the OXDP setup, it seems that you buy the modules and they have chill plates through which you would route the cooling system. It seems that OXDP also specs in the AEM BMS system which uses CAN-based modules that allow the head BMS unit to talk to each of the module boxes. I need to dig into this further but at face value, this seems pretty straightforward to use.

One area of concern for me is that while the OXDP battery modules seem to be based on the LG Chem pouch cells.
Q: Aren't these the same cells which are having issues with Bolts catching on fire? I have a friend who's Bolt seems to be in the process of being bought back/replaced.
My wife says that I should start a new project to keep me sane during this pandemic since I'm no longer racing with my track car or UTV. My initial desire was to buy a forthcoming z06 C8 corvette but considering I work from home now and am no longer driving much farther than to pick up my son from school, she thinks I won't find nearly as much enjoyment out of just "having" this car than building a new one.

Being in California, my choices are traditional engine swap using a 50-state legal crate (the e-rod LS swap @ $12-15K) into a 95 or older donor or something cheaper into a pre-1974 chassis. At the end of the day though, I'll end up with a car that if it takes me a while to build (call it a few years), I expect I will only have a few years (IMO <10 yrs) to enjoy it while a) gas is affordable and b) California starts cracking down further on gas-powered vehicles.

This has led me to consider an "interesting" car, with a timeless look, and doing an EV conversion on it.
This isn't something to build and then resell later; I would want to keep it for the rest of my life and fortunately, I have the garage space (even in SF) to do so.

Anyway, my wifes only stipulation is that she wants a car that seats 4. My son is only 6 so even a 911 sized back seat will be sufficient.
  • Use-Case is not as a DD (I have an appliance - a white Prius - for that) but as a car to enjoy on weekends and for other errands. I don't mind having the car in pieces for an extended period of time as I find THAT more enjoyable vs just writing checks and having someone else do the swap for me.
  • Given the budget, I want a donor will all the trim/minor switch bits in the $20-$60K. Having the car running would be a plus because I don't mind enjoying the car as an gas powered vehicle while I fix up the other systems which will likely need work (suspension/brakes).
  • My expectation is that the Tesla DU based EV kit (like the one sold by electricgt.com) will run me ~$40-42K. I'm OK with that even though I recognize I could buy a whole poverty spec Tesla for that price (which I don't want). Based on my research, it seems to be a fairly "straight forward" swap with the hardest custom parts will be building your own battery box and the LDU mount bracketry.
  • I want something nimble which means decent handling with a preference for the engine being in the middle (never had one).
  • I'm not afraid of tearing apart a car and replacing/upgrading whole systems with that. I've done that with my lemons track car (V6 -> V8, automatic -> manual, complete car harness stripping/rebuild, brake/caliper upgrade, DIY suspension using parts meant for another car, and tweaking the ECU firmware using Moates quarterhorse).

I have one 70s exotic in mine but am open to suggestions.
  • I did consider the volvo amazon but the trim bits/parts availability worries me. I'm also not 100% sure handling will be great and I suspect I'll have to spend a lot of time dealing with that.
  • The BMW 2002tii is another option (wife likes the timeless greenhouse) but Id like the engine in the middle.
  • Finally, the 911/912 variants seem like a good mix of parts and EV KIT availability but they don't speak to me (capable car but there are plenty around).

Anyway, I'm also interested in feedback on the ElectricGT kit.
It seems like it has all the parts I need and the AEM VC software has a lot of control functions I would need to tune the car for driveability -- not everything is lived a 1/4mi a time at WOT
I see that its their own battery modules using LGChem pouches but I need to do more research on them.
Q: Are there other EV kits I should consider?
If you could find a wrecked one, a DeTomaso Pantera would be an interesting car for an EV swap. ;)
 

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The chill plates are not nearly as effective in the OXDP modules as the snaking coolant lines in the Tesla Model S/X modules. They do use pouch cells in the OXDP modules, but the failure incidence on the LG pouch modules is so low that it's not worth worrying about. There's way more likely ways to start a fire in a conversion than a folded separator tab in one of your pouch cells.

Also, just to make the cost difference more clear between the Tesla modules and the OX Drive modules:

I bought 10 Tesla modules for $950 each. $9500 for 53kwh of capacity. To get 53kwh with OXDP modules, you would need 20 2.66kwh modules at $968 each. That's $19,360! More than double the price for modules without integrated cooling and heating loops, and without a proven track record. Tesla modules are so good that you will find almost every high end, long-range conversion uses them.

As for BMS options, the SimpBMS is the way to go if you use Tesla modules. It wires up to the balance boards on each module and is relatively inexpensive and easy to set up. The SimpBMS takes the place of the master BMS in the Tesla, so you don't have to replace the OEM PCB boards, just connect signal and 5v wires to them from the SimpBMS. A number of people on this forum have used this BMS in their conversions (myself included). I ended up liking it so much that I brought it over for sale in North America, since it was previously only available in Europe. I don't know of any other BMS that controls the OEM boards in this way, except for the EVTV Battery Module Controller. I've yet to see one of these in use in an actual conversion, but I'm sure it works great. EVTV has been a good EV parts retailer for a long time.

Almost no one keeps the Tesla modules in the original housing, as it rarely can fit in the converted vehicle. Instead, the modules are removed and arranged in a configuration that is more suitable to the structure of the vehicle they're going into.

I'm not sure what you mean by the AEM BMS. I don't believe AEM makes a BMS. They do sell a controller (VCU) for Tesla drive units that is quite popular. But that controller doesn't have any BMS functionality.
 
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