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Discussion Starter · #1 · (Edited)
1) Your skill level with auto mechanics and fabrication

I have been driving (and in direct correlation, learning about cars and parts) for the past year. I currently have an auto subaru legacy 95 (fantastic car) Its taught me a great deal about how cars work mechanically but especially how subarus work. As for fabrication, I have zero experience outside of clipping out mounting brackets from sheet metal with sheers. I've been excited to try welding however so if enthusiasm counts for something there is that.

I don't know very much about EVs except the basic concept of how the 2 systems (AC/DC) work and components involved.

2) The range you are hoping to get (how many miles/charge)

Honestly I really just need it to get me to work and around town. I'm thing 30- 50 mile range is all I really would need. I understand lead acid is currently the cheapest battery option and until tesla floods the market with cheap lithiums I'm alright running an acid setup.

3) What level of performance you are hoping to get

I absolutely fell in love with the idea of Evs being able to launch so freaking fast. I don't consider myself a drag racer by any means but I do like the idea of smoking cars of the line. Thats not so say thats all I want and expect, its more of a good goal to shoot for. As far as performance I'd like it to be able to do 80-90mph but its NOT an ABSOLUTE necessity. I do think of this as an around town car so I'm ok if it tops out at 50mph. Given that it is a DC setup that I would shoot for to get my feet wet with EVs, I do want it to at least get off the line quickly. (I would like to try autocrossing it)

This video gets me excited about doing a conversion: https://www.youtube.com/watch?v=cjQtrysPzVI (I know I can't hope to hold a candle to this level, but it gives me hope for where EVs are going and they can be a viable replacement for gas cars)

4) How much money you are willing to put into your project

If I was any cheaper they'd call me Mr. Krabs. Obviously the Lead acid battaries and DC motor will help keep costs low but I am in no hurry to build if I can have great deals and save money.

Bottom line if I spend $3000 tomorrow (to have everything I need) or $1000 (car not included) over next 2 years or so, I would think it a good day. Tell me I'm not absolutely batsh:mad:t for having such an expectation?

5) What parts you've already considered, if any.
Lead batteries
DC motor (used 9inch forklift from salvage)
Manual transmission RWd car (I want to learn stick shift before converting to learn the skill) I am currently not planning to convert the subaru for several reasons: adapter plate needs to be more complex as the fly wheel sits inside the engine rather than trans, auto trans is inefficient for conversion, awd will rob efficiency. Plus I always wanted a Z car, here is one more excuse to buy one. (fear not, I'm planning to find a rusty looking one and patching up rust areas on my own, Its more work but I want to also learn welding.



Now my questions:
What dc motors should I be looking for? Is 9 inch forklift motor enough for my needs? what difference does an 11 inch have? Can you explain how voltage and amperage relates to performance of a motor and what numbers I should be looking for.

Are there lighter weight lead acid batteries out there that I can use than the fat old school 12vs that run a car? How much voltage am I looking for and How many should be put in series v how many should go parallel?

Can Some one please link any good articles on building an EV and especially a z car?

I've been scrolling through "Electric cars are for girls" and "forkenswift" websites, as well as "electric subaru" I still feel like I do not understand the very basics of motor + battery performance. Basically the place that I'm at is I know Impulse9 and Warp9 are motors I can use, but if I go to ebay or a salvage yard and look at a motor I have zero flip-flopping idea if the motor will make a monster dragster or a limp wristed turd. I also don't really understand amperage and how that translates to performance.

Any good youtube channels for budget ev builds? I've seen several videos but nothing really anything explaining motor performances that I've seen I may be wrong.


Side note: How does electric overdrive work?
https://www.youtube.com/watch?v=xy3Po20XLlg
https://www.youtube.com/watch?v=ZAwIsKC7ROQ @ 4:44

I understand the basic concept of 2 motors bolted together, receive power in series, overdrive activated, they switch to parallel. This I get what I'm having a hard time with is that the motor controller shuts dow? and then restarts and rewires the motors? how does it reset itself? what can go wrong if the controller shuts off but doesn't restart itself?

Also I undertand that a dc motor you don't want to run without a load on it, please explain this to me a bit further. Does that mean at full "throttle" or with any load? talk me through this if you would... Say I have my 280ev that I wanted to build. If i disengage the clutch from the trans and I "rev" the motor, will it explode fantastically? If I floor it will it break? Say the motor is only able to do 50mph, If I "redline" it will it break down or will it casually just hold 50mph?


Sorry for the many questions, please be gentle, I'm still brand new to EVs.
Let me know any great resources to help me out
 

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Hi and welcome:

Lead is dead. Unless you don't intend to drive it and it's just a project for proof of concept and fun, get a pack from a wrecked Leaf or Volt. Volt packs, at around 16.5 kWh, can be had in the US in the $1500-$2000 range which is cheaper than lead. Your 30-50 mile range goal will be no problem with a Volt pack.

If you have no fabrication experience, the cheap hard-work route of going with an old DC forklift motor and building your own controller is going to be tough for you to accomplish. People with good fabrication skills can tend to have problems making the required transmission mounting plate, so you'd need to count on having someone do that for you.

Can you do this for $3,000? Probably not realistic. At least $5,000 to have a minimally outfitted conversion is more likely. If you want it to be easier and more reliable, you need to spend more still. With a Volt pack I could have done my "easy", reliable AC conversion for about $10,000 USD.

Another option is to buy parts from a conversion that someone is done with. It could save you a few bucks for sure.

Others can answer your more detailed questions.
 

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Discussion Starter · #3 ·
That's a good idea! What is the chemistry of a leaf or volt pack? Does it require any BMS other than what the car uses? Do you have to program the stock BMS that attaches to the pack? Btw what do you think of Prius batteries?

Yea I was sort of figuring I needed a machine shop to make the adapter. I'll see when I come to it, first I need a car and I need a motor.

Is there a good place to buy conversion parts?


Thanks for the advice, really appreciate it!
 

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1) If i disengage the clutch from the trans and I "rev" the motor, will it explode fantastically?
Yes...

If you want cheap and performance:
-Chevy Volt battery
-Modified used forklift motor
-Used 1000 Amps controller
 

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I like the Prius cells, but they are not cost competitive with Leaf and Volt cells from what I've seen. They are in high demand for rebuilding/replacing Prius packs, so you'd easily pay $500-1000 per kWh.

Rob
 

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I got my used 16kWh Volt pack (bought from the Netherlands) for 88$ per kWh. Still working like a charm. Just saying...:)
 

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I got it from a breakers yard at 1250 euro. I did find some offers for over double that price though.
 

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Re: Planning Datsun 280z conversion + que

Both Leaf and Volt packs are high energy density Li ion, and yes both require BMS for charging and to avoid over discharge. Some get away without BMS by basically acting as their own BMS - that's possible with forgiving chemistry like LiFePO4 but not recommended long term. Some reading here and care with the batteries is required to avoid big problems- some here have had fires. The original car's BMS may be difficult to reuse but other options exist. Look at Elithion, Orion and the miniBMS. The advertisers here sell conversion parts.

Most motor/controller arrangements use an encoder to avoid over speed damage to the motor, and for other reasons too.
 
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