[jbman]

Hello, folks!

I'm very new to the electric scene, but I am familiar with ICE cars. I've done an engine swap in a jeep, helped with some clutch and transmission replacements, and done everything on my '66 Mustang short of rebuilding the engine myself. I'm familiar with all of the standard systems, so I have absolutely no concerns as far as the car itself and the standard systems in it.

What I am not familiar with is how this goofy electric motor works! I decided that I want to use a 3 phase, AC industrial motor. I found one that I like for a good price. My concern is how to power it, and how to link it to the drivetrain. From what I've been reading, I can wire up a bunch of batteries in series, and then run that through an inverter, through an AC motor controller, and finally to the motor itself. A variable resistor of some sort is actuated by the throttle linkage, and away I go. I figure I'll get a vacuum pump with a hobbs switch for the brakes, and either an electric power steering pump (I have one from a Mini in my Mustang), or some sort of EPAS column.

I'm not certain what vehicle I want to swap, yet. That's the easy part, in my mind, and cheap beaters in reasonable shape are plentiful.

I'm struggling to find an inverter, and I'm not even sure what rating of inverter I need. The motor I'm looking at is rated for 11.5kw, and it says 20 horsepower on the tag. Likes like a pretty big boy! Do I need an inverter rated for 11.5kw (plus whatever safety margin) constant? The motor I'm looking at will run on 230 or 460, is there any reason I couldn't wire the batteries in such a way to get the 12/24VDC that many of the inverters I'm seeing require, and use the 230VAC output for the motor? I gather that more voltage is less amps is less heat, so should I go for the 460 instead?

The motor I'm looking at has an output shaft that looks close to 1.6 inch with a pretty hefty keyway. The flange on the shaft has bolt holes, so I'm sure it would be possible to bolt it to a gear, or pulley, or put some sort of yoke on it.

Given these variables, should I start over and find another motor? Is there a place to get an inverter for less than a few grand? It seems like a lot of people are making their own; fabrication is not my strongsuit, nor is electrical just in general. But I'm excited to learn as I go here.

I've been Googling for three days, and I'm struggling to find some solid answers. Thanks for reading, and for any information you can send my way!

 

[madderscience]

If you are going with AC it's very difficult to mix and match motors and inverters unless you are an expert on both. This can be done with DC series wound forklift motors as the number of variables involved are far less and can be boiled down to whether the motor is physically large enough, has good enough insulation, big enough brushes and can be timed right. With AC the motor insulation, number of poles, delta vs. wye winding, and a gazillion other factors are involved.

The motor you have found might well be big enough to power your vehicle, but it probably isn't ideal. Also keep in mind electric motors are rated at their continuous load, and inverters at their peak load. You want at least 3-4x the inverter peak load rating vs the motor continuous rating. For example my solectria AC system has a 30kw rated motor and an 80kw rated inverter. Its no hot rod, but its adequate.

With AC you need to buy motor and inveter combinations that are known to work together. So look at stuff being sold by EV retailers, and find and attend any local EV enthusiast groups you may have in your area.

Good luck.

 

[jbman]

I was looking for controllers and inverters all day, and I realize what you're saying. Too many variables. The motor I'm looking at is only $150, and I'm planning on putting it in a midget. The power should be fine, but the rest of the electronics has me scratching my head. The primary reason I wanted the ac was for longevity (brushes, etc., not that it's a big deal...), and for regenerative braking (a much bigger deal to me).

Ill see if I can find some more information about running this motor, and I'll look into some more DC stuff. I very much appreciate your response!


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[Duncan]

Hi
The basic choices are
DC - can be cheap and cheerful - and lots of power
New AC - expensive and a bit wimpy
Re-purposed AC motors - I don't think I have seen anybody manage this
Motors from an EV - probably the cheapest and most power

For a Midget I would either use a Series DC - brushes and no re-gen - but you can probably ditch the gearbox as well

Or try and fit a Leaf motor - I would try and get a whole crashed Leaf and use as much as you can

 

[jwiger]

Welcome to the forum, jbman! The way you're talking about "inverter and controller" has me thinking you're looking at the wrong inverters. You don't want the kind that you add to a regular vehicle to turn 12 volts DC into 120 volts AC. The inverter you need is a controller, and very different from the 12vdc to 120vac kind.

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[jbman]

Welcome to the forum, jbman! The way you're talking about "inverter and controller" has me thinking you're looking at the wrong inverters. You don't want the kind that you add to a regular vehicle to turn 12 volts DC into 120 volts AC. The inverter you need is a controller, and very different from the 12vdc to 120vac kind.

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Thank you for that clarification! I have decided to dial back my expectations. I want this whole thing to cost 5k over the next year, so it's going to be a bit of a squeeze. I've got a line on the Midget for $250. I'll be checking it out tonight, and hopefully towing it back to my place! I found a kit on eBay that will probably meet my needs. It has more power than the original Midget engine (not exactly a feat...), and includes the controller, motor, and some odds and ends for $2k. Please tell me what you think of the kit, found here: https://m.ebay.com/itm/Complete-Ele...%3A5e884e6215f0ab66ab226523fffcd401%7Ciid%3A4

That leaves $2750 for batteries and getting the Midget up to snuff. Selling the original motor and some parts should tip that a little more in my favor. Should be doable!

I'm a little leery of that kit, given the price of other motors of similar power. It seems to me that the motor is being overdriven with liquid cooling to meet those numbers... I have concerns about longevity. The pump for the cooling will also eat some power, but installing a small cooler, hoses, pump, and reservoir will be cake.

I'll do some more research on the motor and see what I can find...


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[jwiger]

What do you think the weight of the Midget will be once you strip out the ICE stuff? Also, how much range do you want?

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[jbman]

Curb weight is about 2300 lbs, supposedly. The ice comes in around 250, tranny is 50. Losing the ice, gas tank, radiator, hoses, wiring, etc... I'm hoping to tip in just shy of 2k. I'd like to keep the tranny, I think.

Edit: less than that, actually, once you lose the exhaust system and such... motor and batteries will bring it above the original weight, but it'll probably feel faster with the torque and power curves of electric.

I'd like to get 30-50 miles out of the car on a charge. The more I look at the numbers, the less likely that seems.

Edit 2: curb weight I closer to 1600 according to Wikipedia.


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[jwiger]

Rule of thumb is about 100wh per mile, per 1000 lbs of car. Your weight is realistic. I would have guessed 2500 lbs myself. So figure 250wh/mile. Times 50 is 12,500wh of energy to drive that far. It's a stretch, and you would have to go with used batteries, but I think you could do it.

Don't forget the golden rule of hot-rodding: fast, pretty or cheap -pick two.

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[jbman]

Rule of thumb is about 100wh per mile, per 1000 lbs of car. Your weight is realistic. I would have guessed 2500 lbs myself. So figure 250wh/mile. Times 50 is 12,500wh of energy to drive that far. It's a stretch, and you would have to go with used batteries, but I think you could do it.

Don't forget the golden rule of hot-rodding: fast, pretty or cheap -pick two.

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Haha, right? I may luck out yet with the Midget. The body is suspiciously clean from the pictures. We'll see in person, though. I don't need another rust bucket. I'm not entirely clear about the curb weight of the Midget, though, because Wiki says it's about 1620, which is pretty amazing when you take out the guts. 1200-1300lbs? Yes, please!


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[jbman]

Is there any reason I couldn't ditch the entire drive train, including the tranny? It seems to me that I could mount the motor to the transmission cross member location with some reinforcement, put a yoke on it, and run that through a drive shaft with a slip joint in the middle. Does that sound reasonable? I'd like to avoid as much drive train loss as possible, since the numbers are already pretty tiny. It also reduces the complexity of retaining the clutch and transmission.

I could mount the motor in the engine bay with a longer driveshaft and probably do the same thing, too... putting it under the car frees up room for batteries, though.

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[jbman]

Gosh I'm tired... 60 more miles to home. That being said, I have never seen such a straight car from the 70s, at least not for $250! This thing is unreal!

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[jwiger]

Ditching the transmission is an option, but you would want a motor that can give you more torque than your ebay motor provides. Remember that in 1st gear, most transmissions double the torque of an engine by 3 to 4 times. Most EVs have to double their motor power if they eliminate the transmission.

If the bottom side is as clean as the top side you have a great project car? What's the condition of the 12v wiring? 40 year old wires are always suspect.

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[jbman]

Ditching the transmission is an option, but you would want a motor that can give you more torque than your ebay motor provides. Remember that in 1st gear, most transmissions double the torque of an engine by 3 to 4 times. Most EVs have to double their motor power if they eliminate the transmission.

If the bottom side is as clean as the top side you have a great project car? What's the condition of the 12v wiring? 40 year old wires are always suspect.

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The car is 100% rust free aside minor surface rust here and there. I know stuff always pops up, but I checked everything. Floor pans are clean and smooth. I'll check it out in the morning and see

As far as the tranny... that ICE probably makes very, very little torque at low RPMS. It wouldn't surprise me if that motor at least matched it XD I'm looking at other motors as well, but that one seems to have respectable power. A little expensive, though... bleh.

1st gear appears to be 3.4~, and the rear end is between 3 and 4 from the factory. Maybe you're right about the tranny.

The torque at 1k RPM from the ICE looks like about 27.5 ft lbs. the tranny would bring that up to 93.5 off idle, and it increases from there... the electric motor beats the ICE, all other things being equal, but the ICE does better through the tranny for takeoff than the motor does with direct drive. I shall have to see what else I can arrange!

I'm unclear on the state of the wiring, but we shall see in the AM.

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[Duncan]

Hi
That midget is far too nice to put that ebay motor in - not enough power not enough volts, I predict that it will be a slug

A Midget is not a sophisticated car! - it will be better with a DC motor and a decent bit of power

http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan

My forklift motor cost $100 - the controller was $600 and it was enough to remove the need for a gearbox so that the motor went were the gearbox would have gone and freed up the entire "engine bay" for batteries

I used a Chevy Volt battery - much much cheaper and better than using Chinese cells

 

[jbman]

Hi
That midget is far too nice to put that ebay motor in - not enough power not enough volts, I predict that it will be a slug

A Midget is not a sophisticated car! - it will be better with a DC motor and a decent bit of power

http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan

My forklift motor cost $100 - the controller was $600 and it was enough to remove the need for a gearbox so that the motor went were the gearbox would have gone and freed up the entire "engine bay" for batteries

I used a Chevy Volt battery - much much cheaper and better than using Chinese cells

Well, I'm more than happy to save some coin I'm trying to understand how the forklift motors are generating sufficient power. Is everyone driving them above their ratings? I saw that you went with a Hitachi forklift motor. It sounds like I should find the highest possible voltage, largest possible motor if I want to do direct drive. Is that accurate?

Also, the eBay seller got back to me about that motor... it's only rated for 25 ft/lbs. We can throw that out the window! Searching for forklift motors now...

 

[Duncan]

Hi
There is a thread on using forklift motors - worth a read

Basically there are two useful sizes - 9 inch in diameter and about 60 kg - and 11 inch - 100 kg
My motor in the forklift was 48 v and 200 amps - at that it would last forever

I started feeding it 144 v and 500 amps - that was good!
In something like Midget that would be able to break the rear tires loose and would give a top speed of about 80 mph

In my car with 55% of the weight on the rear wheels I have gone up to 1200 amps and 340 v
That is scary! - I drive at 45% current on the road - 540 amps

I would suggest
a 9 or 11 inch motor
The Paul & Sabrina Controller - $600 as a kit
Chevy volt battery - $2000

This will give you enough oomph to give anything else on the road a fright

 

[jbman]

Hi
There is a thread on using forklift motors - worth a read

Basically there are two useful sizes - 9 inch in diameter and about 60 kg - and 11 inch - 100 kg
My motor in the forklift was 48 v and 200 amps - at that it would last forever

I started feeding it 144 v and 500 amps - that was good!
In something like Midget that would be able to break the rear tires loose and would give a top speed of about 80 mph

In my car with 55% of the weight on the rear wheels I have gone up to 1200 amps and 340 v
That is scary! - I drive at 45% current on the road - 540 amps

I would suggest
a 9 or 11 inch motor
The Paul & Sabrina Controller - $600 as a kit
Chevy volt battery - $2000

This will give you enough oomph to give anything else on the road a fright

I found a couple of 11 inch motors from forklifts. I also found an ADC FB1-4001A for 300. That would be my preference. I'm trying to work out shipping arrangements. If the ADC motor falls through, I'll get one of the fat forklift motors I found.

As far as the midget, I just picked up a top, found some wheels/tires, and some little bits and bobs like a window crank and an antenna to start cleaning it up. It's in much better condition than my mustang was when I started on it, so I'm happy for an easier project! It definitely needs some shocks now, and maybe some springs later. I need to get a line on some small seats that wont look outrageous, as well. I also found some nice repro door panels, though I wouldn't call mine awful, I'd like to replace them. The brake system is very high on my list as well. I have been able to dig into it yet, but I expect to replace 90% of it. The steering column is a little worse for wear visually, but a new cover, turn signal switch, and ignition switch are probably all it needs. The car has this adorable rack and pinion, and turns very, very easily even when standing outside of the car and just leaning down with one hand. That being said, parts availability for this little thing is almost as good as it is for my Mustang!

I looked up the P&S controller, and they're selling it as a kit for $700 unsoldered. If the unit were fully assembled, I'd happily buy it, even at a higher price. Soldering boards is not my forte. I'll see if I can find any reasonable alternative. If not, I'll take that on.

I found a used Curtis 1231C-8601 at a reasonable price. Is a used controller a good option, or should I spring for new? I am unsure how these things fatigue.

 

[jbman]

I was looking for a forklift motor, and I did find several that matched your description, but they were prohibitively expensive. Called/email industrial repair joints, Craigslist, eBay, etc...

I finally landed a K11 at what I hope is a good price, new in the crate. Compared to the prices of the forklift motors I could find, I'm happy with the Kostov.

I pieced together the parts for a direct drive setup, though I haven't purchased anything. I need it all mounted before I can measure the length for the driveshaft. I'm planning on mounting the motor in a cradle suspended between the stock engine mounts. I'd like to mount it low enough to allow the drive shaft to pass all of the way through, and maintain a good angle.

At this point, I'm trying to find a controller that will push 250V at 1k amps. I've decided against that Curtis controller I had mentioned earlier. I don't know if I'll use all of that power right now, but I'd rather build to the capability of the parts and spend a little more on the front end, instead of buying everything all over again in the future. Does that make sense?

I'll deal with batteries and a charger soon. I'm looking for a volt battery like you recommended, and I found a few decent deals so far. I think those batteries will work well.

 

[Duncan]

Hi
Try and fit the motor a lot further back - ideally where the gearbox normally lives
For weight distribution and for battery space
Batteries are bulky and you really want them as low as possible - in my car the whole "engine bay" is for batteries and I could not fit my whole Volt pack - I fitted 6 off 2Kwh modules and 2 off 1Kwh modules but the remaining 2Kwh module is sitting in my workshop

Forklift motors - you need to go to the forklift repair place with cash in hand - they keep motors "Just in case" then scrap them off - normally the day before you visit

I'm using the Paul & Sabrina - 350 V 1400 amp controller - I have a Beta version