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I want to build an EV! Where do I start?

829K views 415 replies 165 participants last post by  whelmed 
#1 ·
For all new members and first timers, here is the basic guide to getting started.

If you haven't already you will need to Register to post in our forums

Start by posting a new topic in the EV Conversions Forum.
A good topic might be "Planning <make> <model> conversion"

What you will want to post is:
  • Your skill level with auto mechanics and fabrication
  • The range you are hoping to get (how many miles/charge)
  • What level of performance you are hoping to get
  • How much money you are willing to put into your project
  • What parts you've already considered, if any.
Members will help make recommendations and design assistance is generally good. They won't do all the work for you though so you must put in the time and come back with additional questions.

Make sure to have a look through the DIY EV Wiki, as much repeatable information is held there. If you make a discovery or want to help spread the knowledge you've obtained, please contribute. All registered users can add and edit existing wiki pages.

Once you've got your plan down and have started the build, head over to Technical Discussion to get into details of wiring, mounts, fabrication and any problems you've encountered. More savvy users will be able to assist you with your technical needs there.

If you're looking to build a much faster car or are trying to squeeze more bang for the buck out of your newly converted EV, post about in Performance Discussion.

If you're building or converting a motorcycle, bike or other two or three-wheeled vehicle, a good place to start would be in the Electric Bikes Forum.

As for parts and additional services, there are Classifieds, eBay auctions, and a Vendor Forum.

Good luck with your conversion!
 
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#253 · (Edited)
Re: I want to build an EV! Where do I start?

Hmmm, I must be missing something...

I found this:
http://nl.aliexpress.com/store/prod...or-Led/535200_32414884075.html?storeId=535200

That is 8,8Ah @ 3,7V for 2 bucks.
To make 88Ah (to run 44 miles, see list above) I need 10 cells parrallel.
To make 144 V I need to put 40 in series.
So 400 cells at 2 bucks each makes 800 bucks (plus a lot of work) I have all the capacity I need?!?

Or do the Li-Ions have problems I am not aware of? I know about balancing the cells and I have read about cooling / temp controlling them to avoid fire hazard, I think those are manageble.

Cheers,

Hugo
 
#255 · (Edited)
Re: I want to build an EV! Where do I start?

Well, I might just do that. What would be a sensible way to test them? I have my sights on the 500A ReVolt controller, so a 50A (10 cells parallel making 500A) test for 8 minutes (using 6,67Ah = 75% of the capacity)? Measure cell temp, and repeat a lot of times? I need a way to burn 200 Watts...

As a start I requested the datasheet from the seller. Let's see what we get.

Hugo
 
#258 ·
200 mile range (presumably, at 60mph or so) in a vintage F100 is going to require a very large and expensive battery pack. The very aerodynamic Tesla model S 90 can get about 300 miles on a 90kwh pack. The aerodynamics on your truck are going to be much worse, you would probably be looking at optimistically, half the efficiency.

So if you were able to transplant the drivetrain from a Model S into your truck, you would probably have about a 150 mile range. If driven more slowly, like 45-50mph, it might be able to do the 200 miles though.

As for hub motors, Nothing exists in the hobby/DIY space that can do it. Instead, Find a good sized (11" minimum, or 13" diameter DC motor or a large Siemens AC unit, and either use a 3spd stick or direct drive a part time 4wd transfer case. Optimize the axle ratios, probably 4.77 or 5.xx. Run locking hubs on the front axle so that you can disconnect the entire front half of the drivetrain. Put full synthetic non-hypoid gear oil in everything and run narrow highway tread tires, like 235/85r16's. A belly pan would probably help.

Best example I know in my local EV club: F250 supercab 4x4, 60kwh battery (2.5 nissan leaf cells) 6000lbs, dual (siamese) 9" motors, 70 mile range at 60mph.
 
#260 ·
Hi friends , i am mohan bhupal from india , chennai the so called Detroit of india, i dont own a car yet but i am sure that i dont want a gas car. I want to convert a hatch back to electric but have not decided which model as the"donor car" with kerb weight of 1000kgs and gross weight of 1500kgs after conversation , it will be a city comute car and a to office and back car,may be occational gradient of about 5 degrees ,max speed of 70 kms / hour and range of 100 kms/charge. I would like to have AC,Air Bags and ABS.

I am very intrested in an AC motor system and suitable controller and required battery pack.

I am a diy person but have little hands on mechanical work so i plan on using experianced workers for all my work but under my instruction.

I require your best wishes and advices for my projects.:)
 
#264 ·
I have owned a yellow 1971 VW Beetle for the past 45 years which I have used as my daily driver. I now want to convert it to electric as I have other vehicles for long distance driving.

I have an electrical engineering background and have serviced most mechanical aspects of the VW for the past 45 years. I am still hoping to drive the electric conversion to work but probably not on the Interstate. The range per charge I am hoping for is 30 miles. I will have recharge capability at work. I am willing to spend $5,000 at least. I am considering a DC 72 volt system thinking that I could achieve maximum speeds in the 45-50 mph range.

Any suggestions would be welcomed!
 
#269 ·
I want to own an EV, I might just have to make it myself!

Hi Im new to this forum. I want to own an EV and it may be that the best way to do this is to build one.

I will give you a few details to outline what Im thinking.

Some time ago I was inspired by Kiwiev Gavin Shoebridge (I’m also from New Zealand, Go Gav!)… and purchased his online eBook.

For a short time I owned a Toyota Estema 2.4L 7 seater van and liked it except for its hunger for fuel. At the time I wondered about converting it to an EV.

I currently have the opportunity of getting a 1996 Estema, and because it is at the right price, wonder if it would be a good donor car for an EV project?

Other models were called the Lucida or the Previa (wide body) or the Tarago in Australia.

One reason for this is that I think there is plenty of room for batteries under the floor. I don’t know if this has been done and want any advice from anyone who has experience.

I wonder if a good idea would be to bolt an electric motor onto the existing auto trans, either using an external pump to keep the trans pressure up at standstill or simply ‘idling the electric motor’.

The power steering needs to run, is it plausible to run an electric motor to spin the existing pump via belt drive? How about running the front ancillary drive system (Supplemental Accessory Drive System, or "SADS.") which is on these vans via an electric motor? This could be turned off when the vehicle is moving and only come on when low speed or stopped, even possibly used to power the ac although that is not necessarily a priority for me. Alternatively, is it possible to run the SADS off the front of the drive motor?

A vacuum pump for the brakes seems straight forward enough.

I would like the van to be able to go 100km on a charge and up to 100km/h. It would mostly be used as an urban day runner, but occasional 50km (100km round trip) trips to other towns. Most of the use would be in basically flat terrain.

In New Zealand at the moment you can buy a second hand 2011 Nissan Leaf for as low as NZ$16k (about US$11.6K). Im thinking its ok to spend 10 or 12K (about US$7-9k) to make the van a runner. Aside from the cost, I would like to have the experience of doing the conversion and include my son in on the project too.

Im good with engineering and limited with battery knowledge, this means that I can ‘see’ myself making this work using a 144v Lead Acid battery set up (maybe limited to 60km range) and so not reaching my 100km goal within a budget, but I know with some help I could learn and work safely with LiFePO4 batteries.

So, in summary,
1996 Toyota Estema EV conversion.
Use existing Auto Trans.
Run ancillaries off another electric motor.
Use 144v system with suitable batteries to achieve 60 (preferably 100km) range at up to 100km speeds.
Mainly used for urban flat daily commutes.
Budget up to NZ$12k.

Please comment and offer any feedback. What do you think, am I dreaming? Do you think my goals are possible?

I am really interested to know if anyone out there has any experience with converting a pre 2000 Toyota Estema, Lucida, Previa or Tarago? Has anyone done this?

Thanks heaps and thanks Gavin for your inspiration!

Garth.
 
#270 ·
Re: I want to own an EV, I might just have to make it myself!

Hi Garth
Where are you - I'm in Gore
I've just noticed - Hamilton - so I'm not going to be dropping over!

Forget Lead - its expensive here and 60km is more than you can get with lead! (more like 20 max)

Your best bet would be a crashed Leaf - BUT - you may not be able to get one
And the usual shippers seem to be wary of crashed hybrids/electrics

I got a Volt battery from the USA - total all up about $3,300NZ

There is a hot rod concern here in Gore that supplies both islands with hot rod stuff from California - they brought my battery over and another one that is being built into a BMW in Rolleston

Your project is doable - but the budget will be VERY tight
 
#271 ·
Hi Duncan, thanks for your reply, hey, is there much ev conversion activity in New Zealand? Looking through these feeds it seems that there was lots of interest up to 4 or 5 years ago, then things have quietened down? Is it my imagination or are less people active in ev conversions now?

Kind of funny, watching things change, for example when I purchased KiwiEV's e-book a few years ago, Musks Model S wasn't being produced... We are seeing an evolution taking place... cool!

So, you haven't heard of anyone converting an Estema?
 
#272 ·
Hi Garth
There is still some activity - probably more than before

Two things have changed
(1) You can now get the parts to make a decent machine
(2) You can now buy a decent EV

A lot of the people who converted because they wanted an EV can just buy one
We are left with the "Hot Rodders" who want to convert

As far as your van is concerned - are you trying to "save money"? - or to build a fun project?

If it's "save money" - then it's not going to work!
Any modified vehicle is always more expensive that the "use a decent old clunker" strategy

If it's a "fun project" then are you sure you want to convert an Estema?
 
#273 ·
Hi Garth

As far as your van is concerned - are you trying to "save money"? - or to build a fun project?

If it's "save money" - then it's not going to work!
Any modified vehicle is always more expensive that the "use a decent old clunker" strategy
I want a cheap to run EV daily runner, and like the size, utility, versatility of the van.

After the cost of the mods, what are the real world running, maintenance costs? I expect main electrics are very reliable, but how long do batteries last? I have seen Lead batteries dead after 500 cycles? What about LiFePO4? After paying for these, how long will they last?

Why do you say "any modified vehicle is always more expensive..." It is obvious that it costs a lot to pump money into an old car to convert it and its easy to blow out on the budget, but what i mean is after the build, the ongoing running costs.

Sorry, obviously im a novice at this, also, i would probably find all these answers if i go through more threads on this forum, but i would really like to talk to someone with first hand experience.
 
#275 ·
Hi , I want to convert my 68 Karmann Ghia . I'm doing 65miles per day total travelling to work . I'm located in Quebec Canada so this car will be used in summer only .
I manage a scrapyard for a living so access to auctions and scrap cars and parts is not a problem . I have a pretty good general knowledge of cars , access to very good mechanics and fabricators , shop time , tools and lift .
I will be driving the Karmann Ghia at 120km /h ( 75miles/h) .
My question is simple ; will it be cheaper to buy a damaged ev at a car auction and adapt everything in my car or is it better to build everything from scratch ? I'm pretty new to ev vehicles but I've already converted a couple of gas car to diesel and numerous swaps at this point . Thanks in advance !
 
#284 ·
If you are looking to save money, using Leaf or Volt or i3 or Tesla batteries is a must.

The downside to using a OEM motor is that you would have to make your own adaptor, if you get an AC50 or a DC motor then you can get an adaptor for your VW transaxle off the shelf. EVWest and probably others sell them.

Jack and Brian of EVTV fame built a Ghia, so I would check out those episodes if you haven't yet. They did a nice job nicely using the stock style gauges and installing air conditioning.
 
#277 ·
Hi adphil

Simplest would be to get hold of the bits and fit a DC motor and controller

Best (by a long way) (and probably cheapest) would be to get a crashed Nissan Leaf and fit all of the bits you need
As you have room I would advocate keeping absolutely everything of the Leaf until after you have your car up and working
 
#279 ·
Hi adphil
There are some people already using leaf bits - if you fine something unusual you may end up on your own!
I would worry not about the mechanical/electrical side but about the computer/software side

There seem to be two strategies
(1) - con the cars computers into thinking that they are still in the leaf
(2) - replace the motor controllers "brain" with your own

(2) will probably give you a lot more power but loses all of the other functions
(1) could retain all of the charging and BMS stuff

If you were feeling adventurous how about a crashed Tesla?

The leaf approach is the best/cheapest - but not necessarily the easiest
 
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