Conversion to all electric

[wizkid057]

So, I've been considering and brainstorming a project to convert the CR-Z to a lithium ion powered all electric vehicle.

To do this on the semi-cheap, I'd be constructing as many components needed myself. Most notably by building a custom 3-phase inverter to power and control the electric motor or motors.

So, some basics. To have a rate of acceleration that is reasonable for driving, somewhere in the 40-60 HP range would be needed at a minimum, assuming the weight of the CR-Z doesn't increase substantially.

With the existing IMA motor alone, without the ICE (Internal Combustion Engine) attached, an approxmate acceleration of 2.2 ft/sec^2 could be achieved. This would result in a 0-60 mph acceleration time of around 40 seconds even without any wind resistance (which is impossible...). It would take longer because the drag on the CR-Z at ~60MPH would be roughly 13HP, the most the IMA could make.

So, that said... I'm considering using multiple IMA motors, likely salvaged from wrecked Insights, since they can be found on fleebay for around a few hundred bucks, come with the stator, and are pretty much made for the application.

I figure the original IMA, stacked to 3-4 additional IMAs (using machined adapter plates and a custom shaft to align and link them together) should be sufficient for a reasonable target of 0-60 in say, 10-13 seconds, while also providing for a reasonable range of driving speeds.

Gaining control of the CVT through custom hardware or other means would be an added bonus to tweak acceleration and such. Although, that may be beyond my pay grade so I may have to trade in for a 6MT to make things easier.

One IMA motor draws roughly 10,000 watts of juice. Not counting efficiencies, that means the stock battery could run it at full power for maybe a couple of minutes at most from a full charge. However, the stock batteries will be great for developing the inverter and motor controllers, since even though they couldn't run an IMA for long, they can still run one. So, good for testing.

So, I see a point to start this would be to develop or locate a 100VDC to 3-phase AC motor controller for the 3-phase IMA motor that can be controlled by my own hardware.

Next, its pretty likely that the normal Honda ECU will just have to be scrapped for this project, so, everything that would still need to function that relied on it would have to be recreated in some fashion, most notably the dash.


All of that said, has anyone even considered something like this? Just looking for some input/opinions/ideas/etc.

Honestly, I'm probably not going to end up converting the CR-Z itself any time soon and will likely opt for an easier route using a random manual transmission vehicle with a bad engine or something. In any case, I want to make an EV very soon.

-wk

[jcrhee12]

Sounds interesting. Will be keeping an eye on this thread. Personally I would like to swap out the Ni batteries that we have with Lithium.

[wicked1]

I wouldn't want to use Honda's motors for all electric.. They're pretty well designed to be used with the gas engine. Honestly, best bet for this is to start with picking out an appropriate motor from some industrial equipment or something (Im assuming you want to find things used and piece it together). Then you'll have to purchase the batteries, which you wouldn't want used and will cost a lot!
From there it wouldn't be too difficult to design the motor controller and charger if you or a friend have some EE background.

And about the gearbox.. you don't need multiple gears w/ all electric.. Electric motors usually have all their torque available across their entire speed range. (Think about RC cars when you were a kid.. or look up specs on modern all electric vehicles to get ideas)

[hoisumguo]

You could grab some ideas from Electric Motor Werks.

I just saw them on my work campus. Interesting ideas, but they suck at showing off their stuff. Super road rashed wheels and didn't even bother to wash them. But back to OP topic. Sounds like a kwl idea. I always wanted to see a tesla conversion of the cr-z.
There is a bunch of goverment grants for electric vehicle projects, maybe you could snag some of that dough.

Good luck with your project and definitely post back if you start it up.

-Hoi

[sneak1413]

Now one thing that i have wondered from my limited electrical classes i have took in my MET studies is why don't some of these company's wrap a coil of wire around the axles of these electric cars and use either some permanent magnets or some electro magnets to create an extra source of electricity that woudl be created from the drive shaft on either the front or rear wheels(or maybe all 4). With this extra power you could constantly be charging your main batteries(may not be enough power for that though) or just your small battery to run the side electronics such as radio lights gauges etc. May be something to look into for your project.

[sleighman]

I say find a wrecked CRZ and buy it cheap and then mod. A salvage title would not matter and your daily driver CRZ can be used to travel to collect the parts.

[wizkid057]

Originally Posted by sneak1413

Now one thing that i have wondered from my limited electrical classes i have took in my MET studies is why don't some of these company's wrap a coil of wire around the axles of these electric cars and use either some permanent magnets or some electro magnets to create an extra source of electricity that woudl be created from the drive shaft on either the front or rear wheels(or maybe all 4). With this extra power you could constantly be charging your main batteries(may not be enough power for that though) or just your small battery to run the side electronics such as radio lights gauges etc. May be something to look into for your project.

Basically because you can't get something for nothing. I've heard every idea of this nature, and I assure you if it really worked like that, everyone would have electric vehicles.

If you add a generator of any kind to the car (on the axles, wheels, driveshaft, wind turbine, whatever) its going to "cost" energy to run that device to make it produce energy.

Take your example. Lets say I add a generator of some sort to the rear wheels thats capable of making say, 2000 watts of usable electrical power. Well, in order to make that 2000 watts of power, 2000+ watts of mechanical energy needs to be put into it. That comes to roughly 2 3/4 HP. So, the car's engine, electric or otherwise, be be taxed an additional 2 3/4 HP while going down the road to generate that power. So now the output of my electric motor is cut by 2 3/4 HP or more, depending on inefficiencies. You'll never get back what you put in to drive the generator, let alone anything extra to charge batteries or run accessories. You'll lose power.

I refer you to the laws of thermodynamics if you don't believe me. Most notably laws 1 and 2.

[wizkid057]

Originally Posted by wicked1

I wouldn't want to use Honda's motors for all electric.. They're pretty well designed to be used with the gas engine. *snip*

Well, the thing about it is, they're still just 3-phase electric motors. They have the RPM range needed, decent HP to weight ratio, and they can be found on the cheap.
I don't really see a downside to using them in this fashion, as long as they're appropriately cooled.

Also, using multiple IMA motors in parallel means that my inverter/motor controller can fire up only whats needed, and average any wear from longer driving across all of the motors. Can also make it so that during any cruise, no motor is run at 100% capacity. All in the controller logic, which I could have full control over since I'd be building it.

Another advantage of using multiple smaller motors would be redundancy. "Aw man, an IMA motor died. Oh well, I have 4 more, just down 13 HP." And then still limp home.

A disadvantage would be the electronic synchronization of the motors. The good thing is that there would be no ICE to worry about syncing with, so, shouldn't be difficult.

And about the gearbox.. you don't need multiple gears w/ all electric.. Electric motors usually have all their torque available across their entire speed range. (Think about RC cars when you were a kid.. or look up specs on modern all electric vehicles to get ideas)

I know that technically this is not needed. Of course I could rig up a beefy electric motor straight to the wheels if I wanted. But, personally, I'd rather have some sort of gearbox, manual or CVT, just in case. Especially if I'd be running at under 60HP electric, it would be nice to have at least a couple of gear ratios so not to have to run the motors at full power for moderate acceleration. There are advantages and disadvantages, but, I think leaving the transmission has more advantages.

I say find a wrecked CRZ and buy it cheap and then mod. A salvage title would not matter and your daily driver CRZ can be used to travel to collect the parts.

Yeah, I've been keeping my eye out, but, haven't seen any up for grabs. Lots of Insights, though.

I say find a wrecked CRZ and buy it cheap and then mod. A salvage title would not matter and your daily driver CRZ can be used to travel to collect the parts.

Most of what I've seen are tax credits and after-the-fact type deals. If you know of any specific grants that would help in the shorter term, I'm all ears.

[andrewr]

Very cool idea, going to be hard to pull off though. I wanted to convert a car to all electric once, even have a geo metro to use for it, but I never did for a few reasons.
1) Costs - Need a really big motor with LOTSA batteries to get very far very well.
2) No actual use for an expensive 2000 pound car that can struggles to keep up the speed limit with less than 50 miles reliable range.

Honestly, the reason we don't have masses of EVs isnt because the oil companies are stomping them out. Its cuz the technology required of motors and batteries just isnt there yet. It takes an entire car stuffed so full of cheap batteries its sagging on its suspension to make it 60 miles or the cost of a nice house to have (still a crap-load of) expensive lithium batteries to still barely make it 100 miles. Cars in general are just too heavy, existing batteries weigh to much per their energy density to carry themselves very many miles. Motor technology is... not bad... but expensive once you want one that can handle the kind of power that will give you ICE-like performance.

Thats why I'm all about 2 wheeled electric vehicles now, their power/weight ratios match up better with currently available motor and battery technology which keeps the cost way down. Ive been building electric bicycles to prepare for a full-on electric motorcycle project in the next year or two. I believe I can build a 70 mph all-electric motorcycle with a 20-30 mile range for between 2 and 3 thousand, depending on what specific batteries I choose. To get similar speed and double range out of something as massive as the CRZ will not only be much more complicated, but also cost 10x more. You can reduce cost slightly by increasing your investment of time, but even building your own motor and controller wont help enough to offset the pile of batteries your gonna need.

I don't mean to be a downer, thats just the harsh reality as I see it, from one electric vehicle enthusiast to another. Then again, for all I know your a full blown engineer with the capital to tackle the difficulty of an E-CRZ. Have you built any EVs before? I love seing other people's projects

This is my latest project, over 150 miles on it now cruising around town, to work, to school, etc. Its a long ways from an electric motorcycle, but you gotta start somewhere
Super Scamper - My 2nd Electric Bike Build | Facebook

This was my very first [sucessful] bike project, simple electric bicycle conversion using parts from grandma's old electric wheelchair. Its ugly, but it worked and hardly cost me a benjamin.
http://www.facebook.com/media/set/?s...1&l=7c969be6af

[wizkid057]

You make valid points. I can't argue with most of it.

You are correct about the batteries being the bulk of the cost regardless of the other components. However, even that cost can be offset by some good old DIY. I don't think I plan on having a total mutt for a battery made up of whatever I can get cheap in the lithium ion department.

As for making an EV before, no, I haven't. Not a full blown street EV anyways. I made a lithium ion go-cart a few years back that was pretty badass, though, lol.

So, its a doable project, in any case. Just takes a lot of time and patience.