# motor choice



## B.C. (Oct 7, 2009)

I'm new to the EV game. I want a car with performance and a 50 or more mile range. I have been looking at this site for a day and there is some excellent posters here with a lot of knowledge. I would rather not try to reinvent the wheel so my questions are. Who are the best motor manufactures? I don't fully understand the power curve on an electric motor but I think I should plan on using a transmission. Is this correct? There are a lot of choices to be made in a motor selection and as this seems to be the most expensive single component should I start with the motor and build around it or take a different direction for my build plan. 
I know these are a lot of basic questions and I will continue research into this project but I only have about an hour or so a day to dedicate to it so any help would be appreciated. 
My goal is to build a practical, cost effective EV that has the style that people would want to be seen in. I think this could make a good DIY project that people would be interested in. Thanks in advance for your help.


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## MJ Monterey (Aug 20, 2009)

My opinion is that the motor and controller as a package will guide your build.

Motor and controller will drive your requirement for trans and battery pack.

Are you looking for a one off build or a replicable kit?

Replicable kit requires current product form a solid source. I'll give you my high level run down and let others fill in details. 

Four motor manufacturers come to mind for new product. 

D.C. is dominated by Netgain/Advanced and Kostov. The D.C. motors will also need a controller added to make a basic package. The controller has been making significant strides over the past few months. If you decide to go D.C. a seperate thread may be a good idea.

A.C. has two significant players, there are others but the cost becomes high or the manufacturers only want to talk to major manufacturers. Solectria has a few distributors and has been around for many years converting cars and trucks to electric. HPGC is better known for golfcarts and movie cars however their A.C. product line is getting powerful enough to use in smaller road cars.

I'll throw this back to you for questions and the others for added details on real world data.

Jack


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## B.C. (Oct 7, 2009)

I don't mind a couple of prototypes but the first one needs to be the foundation for the next one. We build kit cars now and the advantage we have over our competition is that we build turnkey cars ourselves. That way we can see the problems first hand and correct them. 
Ideally we pick the right EV drive train to start with and stick with it. It is our hope to be able to offer a complete DIY kit for the home builder as well as offer parts and pieces all the way to turnkey's. Our focus is building the platform, using proven technology and parts from the EV world for the drive train.


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## MJ Monterey (Aug 20, 2009)

O.K. so to go to production right now, with street rod cruiser/performance goals, I would start with a Netgain 9" and make allowances to accommodate Netgain 11" (standard and high performance cut). They are proven reliable from proven domestic producers.

Controller choices:
1) Solitron1: designers and engineers (hardware, Tesseract and software: Qer) are on this board and I like there approach for design and implementation.

2) Logisystems: They are working to get the product up to snuff and are giving good customer service but too many have blown up recently. (design quality concern)

3) Zilla: They dropped from production for a while but EVComponents has committed to restart production. These things are "THE" controller for performance. They have a history of long lead times though. Hopefully the production delays are resolved with the new partners. Keep an eye on them, if production gets stable I would bump them to #2, maybe #1 but personality wise I like the new guys (Solitron)...


Trans. 
Lightweight car: Manual shift powerglide shorty with torque converter eliminator
Mid Weight: th350 again with torque converter eliminator.

If you must go manual I would look for an aluminum three speed. I think some are done up for circle track use. And keep the clutch, most folks do not tolerate clutchless shifting well.

My straight up opinion, others may vary.
Jack


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## Bowser330 (Jun 15, 2008)

IMHO

For budget performance....

I would do Kostov 11" with Soliton-1 or Zilla 1K

Build the pack up to ~300V nominal

And a strong transmission/rear-end...


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## B.C. (Oct 7, 2009)

I haven't tried hard but have not found a good place to purchase the Soliton-1. Thanks again for all the help. this is a whole new world for me and I need to do a lot more studying to be able to ask good questions. I just started looking into batteries. 
Am I very for off when I think the cost of the power plant less batteries will be somewhere around $6000


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## EV-propulsion.com (Jun 1, 2009)

BC,
Welcome aboard-
We have the Soliton 1 available
http://www.ev-propulsion.com/controllers-throttles.html
if you haven't read the build thread here is a link to it:
http://www.diyelectriccar.com/forums/showthread.php/new-controller-prototype-29062.html
Good luck in your projects!
Mike


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## MJ Monterey (Aug 20, 2009)

Solitron is available here: http://rebirthauto.com/soliton1byevnetics.aspx

$6k does not feel too far out of line, I have not totaled it out but feels right.

I should point you toward a difference between the Kostov and the Netgain Motors. The Kostov are designed to use higher voltage than the Netgain motors. Because of the higher voltage the Kostov will have lower amperage requirement for the same power. With of the lower current less power may be lost in the cables and such and may therfore give a slight favorable bump to efficiency.

The higher voltage will change the character of the battery pack. Were the Netgain pack spec out along the lines of 156v and 200 ah, the Kostove could use 312v and 100ah. Both are about 30kwh (voltage x current) packs just different ways to get there.

Oh, and batteries, be ready for sticker shock in the ball park of $10k.


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## Tesseract (Sep 27, 2008)

B.C. said:


> ..I want a car with performance and a 50 or more mile range. ... Who are the best motor manufactures? I don't fully understand the power curve on an electric motor but I think I should plan on using a transmission. Is this correct? ...


As a controller manufacturer I am technically motor neutral, but I will say not all motors are equal. In the 9" size the WarP 9 is pretty hard to beat, IMO, but in the 11" size the Kostov would be my choice. Both sizes and brands use the same mounting bolt pattern so as long as you leave enough room around the motor you can interchange the two.

My feeling is that unless your glider is really, really light - like 1500# or less - and even with a high current controller (i.e. - 1000A or more) you still want to use a transmission with at least two gear ratios if you want good range AND performance. If fed with enough current, the series DC motor will deliver a tremendous amount of torque right at 0 rpm, so the low gears are not as important, and the clutch - if a manual tranny - is only needed when actually shifting gears (which greatly extends its life). That said, the motor will be a lot happier, and both the performance and range much improved, if you use a transmission. Just two gears seem to cover everything nicely in an EV, though: say, 2nd or 3rd and 4th or 5th. Driving around town in Rebirth Auto's demo vehicle (an old VW bug) you end up just leaving it in 3rd (though the Kennedy Engineering clutch still protests when accelerating hard from a stop in 3rd, and smokes like an opium den if in 4th).

As for a 50 mile range, depending on the mix of driving - with a higher penalty being paid for _highway miles_, unlike in an ICE! - you need to plan on using anywhere from 250-500 Watt-hours per mile (Wh-mi or similarly abbreviated) and you should also not discharge your batteries - if lead or lithium - more than 80%. E.g. - 50 miles of range at 400Wh-mi requires 400 x 50 = 20,000Wh, then divide by 0.8 to get the pack size needed: 25,000Wh (25kWh).

This pack size, in my opinion, totally precludes using lead-acid batteries because of weight. So MJ Monterey is right when he says be prepared for sticker shock when you go to buy the lithium batteries. That said, the total ownership cost for lithium is far lower than lead, and both ownership and operating costs are far lower than the original ICE, so it DOES make financial sense, it just costs a lot more up front to cut the price to go 300 miles from, say, $80 down to $10-$30.

Current pricing on lithium iron phosphate (usually abbreviated LFP) cells is around $1.50 per Ah when all is said and done getting them to your doorstep. At a nominal cell voltage of 3.2V, that means a 25kWh pack would cost somewhere around $12,000, which is surprisingly close to MJ Monterey's estimate of $10,000


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> ... and smokes like an opium den if in 4th....


HAHAHAHAHA

I also choose the higher voltage DC motor....
The Kostov can handle high amperages, albeit for not as many seconds as the Warp, however it will be able to tolerate higher amperages for greater range of rpm (assuming indentical gearing as the Warp) ...meaning better acceleration @ higher speeds....example: 50 to 80mph, The higher voltage motor would have more torque available for that speed range...useful for everyday driving...

Keep in mind also that John Wayland owner of the "whitezombie" dragster drove his 2000 lb. datsun with 11" kostov and 1000A controller (Zilla 1K HV) through the 1/4 mile in 13 seconds with LA batteries...which is about as fast as an E46 BMW M3.....


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> ...
> I also choose the higher voltage DC motor....
> The Kostov can handle high amperages, albeit for not as many seconds as the Warp, however it will be able to tolerate higher amperages for greater range of rpm...


That does SEEM to be the case, but the Kostov's are definitely less efficient at the higher amperage level. The WarP 9 is a good 15 percentage points more efficient at 800A than a Kostov 9 by our measurements... So, while the Kostov 9 is capable of producing a higher peak power than the WarP 9, the extra heat it produces when over-amped is much more likely to destroy it... you know, catch on fire and that sort of thing.


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## B.C. (Oct 7, 2009)

Thanks for this great input. I just had some family medical issues come up so if I don't post for a day or two it's not because I lost interest. Also I just did some ruff numbers and as it refers to the battery pack I can buy over 100,000 miles worth of fuel for $12,000. I say this ONLY because the cost issue does fit into the equation. The cost of an electric motor vs a gas engine is close enough to call it a wash especially if you consider maintenance costs. I know these are issues for a different thread but I just wanted to voice them before I have to go.


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## Woodsmith (Jun 5, 2008)

B.C. said:


> Also I just did some ruff numbers and as it refers to the battery pack I can buy over 100,000 miles worth of fuel for $12,000. I say this ONLY because the cost issue does fit into the equation. The cost of an electric motor vs a gas engine is close enough to call it a wash especially if you consider maintenance costs. I know these are issues for a different thread but I just wanted to voice them before I have to go.


I was just considering this myself earlier today.
I could spend £10,000 on LiFePo4 batteries - 50 x 200ah cells at about £200 per cell at a guess.
I would have a 10 year battery life.
Using the EV for 4 days a week for 50 weeks of the year I will save £20 per week and £1,000 per year on my fuel costs.
Over 10 years I will cover the cost of the batteries at the end of their 10 year, 2000 cycle, life.

I could only hope that the cells really do have at least a 10 year 2000 cycle life.


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## paker (Jun 20, 2008)

With an ICE car in that 100,000 miles you have oil changes, antifreeze, timing belt, drive belts, water pump among other things that can go wrong along with the money spent on gas.


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## Bowser330 (Jun 15, 2008)

paker said:


> With an ICE car in that 100,000 miles you have oil changes, antifreeze, timing belt, drive belts, water pump among other things that can go wrong along with the money spent on gas.


+1 with all the moving parts in an ICE there is a higher chance of something going wrong than in an e-motor...


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