20kw continuous motor enough for small 2000lb 40-45mph car ?

[flez1966]

that golden motor looks more like it would suit a motorcycle then a car.

if your looking to cars, I'd suggest a look at the youtube vids of 'marionrickard' aka evtv.me

he goes on an one and is a bit opinionated at times, but look at the kit he uses, it works.

 

[whatever]

I was also looking into a car conversion, there are a number of different cars that are hybrids which have been around for some time.
They use an electric motor in conjunction with petrol motor, some drive via gearbox some via rear differential. My thought was to find one of these cars
which had been written off and re-use as much as possible of the electric motor drive sections, seems 50kw is common figure thrown around for some hybrid electric car motors. It may be a cheaper option to get a high power car motor.

 

[whatever]

hers an example, toyota prius for $1,000aud ( western australia), a quick search found quite a few being wrecked in australia.
I think lexus 2007 toyota also hybrid

http://www.gumtree.com.au/s-ad/maddington/wrecking/toyota-prius-1999-hybrid-nhw10-parts-wrecking-or-sell-complete/1003371652

 

[rjoe]

I used to have a 94 Tercel, and I loved it -- they are great cars. I highly recommend board.tercelonline.com, which is how I know about this blog by a guy who made an electric Tercel

PS I don't think they ever sold a 99 Tercel in the US.

 

[neptronix]

Prius generation 1: Really ugly and not all that aerodynamic. 6.27 CdA. The late 90's Tercel has 6.26CdA. Gen 2 MR2 has 5.67 CdA, early 90's Nissan 240SX has 5.88 CdA. I'll let someone else fix up that car!

Prius generation 2: You're gonna spend $8,000 here in the USA for one that runs but has a half-dead battery. Or around $5,000 for one that doesn't run ( if you can ever find one ). It's a heavier chassis which will require more power to pull around. A MR2 or 240SX have similar or better better aerodynamics, so the Prius's aerodynamic advantage isn't all that great.

The 3 cars i'm looking at for conversion can be had for $1,000 non-working, or up to $3,000 working. I would be better off going with one of those.

Leaf or other prebuilt car lease: 180AH x 25S of CALB batteries ( 14.4kw-hrs ) would cost me $6,200 ( w/o shipping ). That's under 3 years of $199/mo lease payments right there. If these batteries can last 6 years, then i've got quite a deal.
Downpayments on leases are usually $3,000 or so. My powertrain cost for a netgain motor is $2,400 + shipping.

So for the cost of a 3 year lease, i could almost build my own ~50mph city car. If i stick to city speeds ( 30-45mph ), then the range calculators say that i have a 70-75 mile range at 40mph continuous. that's pretty damn good. Shipping and other miscellaneous stuff like motor mounting plates will drive the cost into the $10,000-$12,000 range. But that's quite a deal VS. buying a brand new electric car.

I can only get away with this because i live in a flat area with lots of frontage roads, and don't, nor will ever have kids. A 2 seater for me, my lady, and groceries in the trunk is all i need.

 

[drewjet]

I think the 9" motor is overkill for a Tercel. I think you could get away with the 6.7" motors and save a bunch of weight

 

[neptronix]

Which 6.7" motor?

http://www.evparts.com/products/str...8-to-96-volt-street-vehicle-motors/mt2114.htm

Here is a 6.7" motor.. it is rated for less continuous power than the 10-20kw golden motor unit i linked. 18hp (13kW) continuous for 1 hr on 120v.

I'm sure that the golden motor with liquid cooling can do 15kw continuous at least.

it's the periods of 30kw-20kw going up hills is what i'm worried about.

There is the impulse / warp 8" which are 106-110 pounds, but they seem discontinued. I can't find any specs on them showing the continuous horsepower.

For 10-20 pound extra, the impulse 9 does seem like a good deal considering that i could run it on 114v later down the road and probably have something that burns a bit of rubber.

 

[Arlo1]

On DIY electric car there is a civic that used a 6.7 with the tranny and does ok but is undersized.

 

[neptronix]

Actually.. I think i may have just hit a home run.. in Golden Motor's ballpark.. :lol:

http://www.goldenmotor.com/eCar/HPM5000B72V6000rpm Performance Data.pdf

http://www.goldenmotor.com/eCar/HPM5000B72V6000rpm Performance Curve.pdf

This 5kW 72V golden motor in particular sure seems to like a lot of load on it. 88-89% efficient from 4000-5000RPM pushing 9,500 watts. This motor also comes in a liquid cooled configuration. At optimal conditions at full tilt, one of these would need to only shed 1000W each. Given that the 10-20kW has the same sized liquid cooling block, then the liquid cooling block on one of these would be capable of dissipating twice the heat.

See where i'm going here with this? here is someone that did a budget metro with 2 eteks. But the eteks only really put out 5kW or under continuous..

Perhaps 3 of these motors, pushed to a leisurely 7.6kW ( 76v x 100A )each, could make for 22.8kW continuous, or 30.5 horsepower continuous. When cruising along on the flats, each motor would only be pushing 2-3kW continuous.

I would hook them up via chain to one big rotating shaft on 2 big mounted bearings that go into the transmission.

33kg = 72lbs + rotating shaft, chain, bearings, sprockets etc = 8-10 lbs additional.
3 x $466 = $1,398 + $200 for the other bits = $1600
3 x 4110 36FET greentime controllers = $474

Before shipping, ~$2100 for all of this.

OK, i believe that i have reached lightweight Budget EV nirvana.

Now the question is - can the greentime controllers do 100A continuous for 10 minutes? or 90A? Maybe John in CR would know :lol:

 

[Arlo1]

I think to push the average car 60mph you use 22 hp. Yes these are very generic numbers but you can accept ~ 15 kw continuous to hold 100km/h. As well how much are the controllers? I think controllers are almost always more then the motor for pmac.

 

[neptronix]

I think to push the average car 60mph you use 22 up. Yes these are very generic numbers but you can accept ~ 15 continuous to hold 100km/h. As well how much are the controllers? I think controllers are almost always more then the motor for pmac.

I'm never going to hit 60mph/100kmh though, so this is no worry.
Utah has lots of long flat frontage roads with max speeds of 35-55. These are actually better to take because traffic on the highway can get REALLY bad.

http://www.johnsavesenergy.com/EVRangeCalc.html

Here is an ev range calculator that seems to give similar results as others i've seen online. It's pre-programmed for the early 90's geo metro hatch, which has +/- 5% the aerodynamics of the tercel i'm thinking of.

Let's do some math on the Tercel.
Let's assume that the car would be 1,700lbs with the ICE stuff ripped out.
Add 100lbs for the 3x golden motor + controllers
Add 350lbs for the 24S 180AH CALB pack ( 13.8kw-hr ) ( 300lb battery weight, 50lb for bms, wires, boxes etc )
2,150lbs.
Add my fat ass.
2400lbs.

Frontal area is 19.6, CDA is 0.32. Block off the front grille, install an underpan and the CD should drop to 0.30.

55mph: 8.81kw
50mph: 7.24kw
45mph: 5.89kw
40mph: 4.74kw

These numbers might not add motor efficiency and gear loss into the equation, so the true numbers might be 15% higher at worst.

The greentime controllers are $158 each before shipping, but i don't think they can push >100A for long. 90A-100A is where i would limit them to prevent blowing them up on hills. It looks like the 72v motor can take >130A for some time, but in order to deliver 130A continuous, i'd have to go with something like the golden motor HPC500, which are $580 each. That's $1,740 worth of controllers.

 

[neptronix]

Arlo, now that you bring up the controller price.. i'm thinking that if i go brushless, i am basically making a bet on the greentime controllers - that they will be reliable, long lasting, and capable of pushing 100A continuous up hills.

That might not be the case. John in CR might know how these perform in real life.

Another motor option is 2 of the largest brushed double stator etek motors.

http://www.electricmotorsport.com/store/pdf-downloads/emc-rt200_data.pdf

http://www.cloudelectric.com/product-p/mo-me1003.htm

Their dyno only runs up to 50v and 6kw though, wtf? at 200A x 72v though, that would be 14,400W continuous. I would have to give them a phone call about this one though.

These would be 39lb each.

http://www.cloudelectric.com/product-p/co-spm72300.htm

2 of these would cost $1,200
2 Alltrax SPM-72300 would cost $920

Total cost would be $2,120. Similar weight as the trio of golden motors.

28kW continuous at 85% efficiency would mean that each motor has to shed 2.1kW continuous. Or at 20kW and 85% efficiency, each one has to shed 1.5kw continuous.

These are ventilated and i think they have fans inside too. If they don't, i could set up a ram air system.

28kw would be 38hp peak. That would be badass on a little car like this considering the torque.

Gee, now i really don't know which direction to go on :lol:

 

[nieles]

what about the smoothness of low speed control?

the brushed motors will do fine in this department, but in general the "cheap" brush-less controllers lack a bit of low speed control.

 

[neptronix]

http://www.diyelectriccar.com/forums/showthread.php/anybody-adc-6-7-8hp-motori-40756p2.html

Here's a guy with a 6.7" motor, who seems rather underwhelmed by it. 60km/h ( 37mph ) when stomping on the pedal on flat ground at 72v. The max voltage for that motor is 96v, which isn't too much more.

Seems that the single 10-20kw golden motor idea i had originally would be more powerful than that.

 

[Hillhater]

55mph: 8.81kw
50mph: 7.24kw
45mph: 5.89kw
40mph: 4.74kw

These numbers might not add motor efficiency and gear loss into the equation, so the true numbers might be 15% higher at worst.


something doesnt add up here ?
I have seen power calculations for Ebikes that show kW number is that range ?
how can a much larger vehicle not need more power ?

I suspect the bigger problem would be how much kW you need for accelerating a 2400lb car from 45 to 50 mph ?
IE: kW's in addition to that 6 kW just to stay at 45mph
Also, you could deduce from those numbers that at 45 mph, a 10 mph headwind will add another 3kW or so ! ( 50% more)

 

[neptronix]

I just got off the phone with the guy at motenergy ( they are always super helpful and knowledgeable when i call them, TOTALLY the opposite of golden motor, how refreshing ).

The spec sheet they have up is for the 48v, but they don't have a 72v spec sheet for whatever reason.
But apparently their definition of 'continuous' is something like 100's-1000's of hours in a 100f room.

The man i talked to said 72v x 200A should work fine, and the efficiency band is very broad, around 90% at that level.
He hinted that the power level is conservative.

Also, the motor sucks in air through the back, and blows it out the front with an axle driven fan. Not bad. You could design sort of a ram air system to help this out.

Attached is a visual on how the air flows, and also a 72v graph of the ME0709. Apparently the ME1003 ( AKA RT-200 ) is effectively a ME0709 with more copper and magnet to it. So the fellow at motenergy says that i can expect this level of efficiency at 200A ( 200A X 72V = 14,400W ).

I think this is the best setup possible. I don't really need all that power, and the 3 golden motor setup would be good and all, but I'll take American built brushed goodness over China built brushless.. it's possible that the efficiency is much higher here anyway.

 

[Hillhater]

Wow ! who was that ?.
Managed to get a reply INTO my post !
Neat trick !

Really? at 40MPH on multiple motors, i only use about 2000W. the ebikes.ca simulator shows numbers like that.

Keep in mind that a bike and rider have AWFUL drag coefficients on an upright bike! like 0.9cD! the frontal area is low, but the cD just kills you! For comparison, the cD of a modern car is around 0.30.

But due to the lower frontal area, mph per mph, according to my calculations, a bicycle can consume around 1/3rd of the power at highway speed versus a car. Maybe you can ask liveforphysics for a confirmation on that :lol:

40mph may only need 2kW, but that next 20mph will need a LOT more !

 

[neptronix]

Heeeyyyy... is it possible to run two brushed motors on one controller?? just hook them up in parallel?
This setup could get even cheaper if so.

An alltrax SPM 72500 could be used.
http://www.electricmotorsport.com/store/ems_ev_parts_controllers_alltrax_SPM-72500.php

380A x 72v makes 27,360W power continuous. 190A continuous per motor.

That's a ~35 horsepower setup for $1,888.

OK, bang per buck ratio has been maximized.

 

[neptronix]

LOL DAMNIT... i'm sorry. I fixed your post.
I'm bad at being a moderator apparently.

I think the 'edit' and 'quote' button are swapped now, OR i am so used to seeing the 'edit' button that i just click on it and assume it's my post.

Don't tell Justin about this, i might have to chop off my pinky or commit seppuku for this dishonor :lol:

Wow ! who was that ?.
Managed to get a reply INTO my post !
Neat trick !

Really? at 40MPH on multiple motors, i only use about 2000W. the ebikes.ca simulator shows numbers like that.

Keep in mind that a bike and rider have AWFUL drag coefficients on an upright bike! like 0.9cD! the frontal area is low, but the cD just kills you! For comparison, the cD of a modern car is around 0.30.

But due to the lower frontal area, mph per mph, according to my calculations, a bicycle can consume around 1/3rd of the power at highway speed versus a car. Maybe you can ask liveforphysics for a confirmation on that :lol:

 

[neptronix]

Allright, back 1 step. Can't use brushed motors in parallel. Liveforphysics seems to have answered that question on another forum. I hate it when he's right.

http://www.elmoto.net/showthread.php?1932-Dual-motor-setup-what-have-we-learned/page4

Two Alltrax SPM-72300's it is, i suppose.

 

[amberwolf]

Heeeyyyy... is it possible to run two brushed motors on one controller?? just hook them up in parallel?

Yes, BUT: if they're not identical (probably they wont' be) they will not take the load the same and the current thru them will be slightly different. This is less of a problem if they are fixed to the same shaft.

Look up "White Zombie" over on evalbum or DIY Electric Car; it uses two motors ont eh same shaft, and using a set of contactors on the controller outputs, it shifts between parallel and series to make things work out better for it's main purpose: dragracing.

FWIW, DayGlo Avenger's friction drive 2.x used two radiator fan motors in parallel on a single controller, and it worked fine, even though they werent' on the same shaft, just with each it's own roller on the rear wheel. I'm sure it could've been more efficient, but since both motors got hot enough on the outside to flash icewater into steam after a while, I don't think it would've made a lot of difference in that particular application. :lol:

 

[darkone040]

i doubt the the golden motor one would have enough torque to accelerate your car to the speed you require in a respectable amount of time..
youll take off from one set of traffic lights and only get to your 40mph by the next set, while every driver behind you is tearing their hair out screaming obscenities..

i say take the warp9 or equivalent they can be run to 170volts or so before the brushes start wearing prematurely, itll have more torque, you can even force air cool them..
you can even pump 100-200kw into them for a small period of time, you-tube white zombie drag car...
wasnt there a thread not long ago in the for sale section where some guy was selling these for $500 each that he got from a bulk auction or something, thats a bargain too, get 2..

the hardest part with all mid drive setups (just like bikes) is getting the gearing sorted out...

 

[neptronix]

The problem with >72v, is that the controllers start to get very expensive very quickly.
I'm not interested in building a particularly quick car, like i stated from the first post - i just need a city commuter.

The duo of ME1003's is definitely enough power. I won't even be driving them to their limits either.

Getting this conversion done in a year would mean that i have to pick up a second job and work my ass off all year long. So the imperative is to keep it as cheap as possible.

I want off gas now, damnit :lol:

 

[Arlo1]

I want off gas now, damnit :lol:

I here you man. That's Why my fiance and I own 2 honda CRX's I almost have enought to do it brushed onther then batteries. But I want brushless like you.

 

[boostjuice]

Hmmmmm, yeah that's something to consider.

The interior of the stator would be really hot trying to ditch 3000W of heat on hills.
Only one side of one stator would get cooled.

Well, you kinda took a crap on my rainbow to be honest :lol:

Do you have any other pics of the interior by the way?

Sorry to mix all the colours of your rainbow and make it brown :lol:

I didn't take any more pics, but here's a good video showing the guts of a HPM10000B after the magnets were overheated/degaussed in a car conversion. It's interesting to note that the HPM10000B stators have double the stator teeth per side and a different winding scheme as compared to the HPM5000B (unexpected to me). However, the crappy thermal path from coils to the factory coolant labyrinthe is clearly evident as I mentioned earlier.

IMHO, the motor's heat dissipation would be better improved by scapping the factory water cooling and simply filling the stator/rotor casing cavity with ATF to a fill height below the bearing housing and accepting the small hit on mechanical efficiency from the added drag. Although the majority of the stator coils wouldn't be submerged in fluid, at least the magnets on the rotor would be continuously dipped in the ATF (well thermally coupled to the casing) on every revolution, and as we know the magnets have a lower max temp than the coils. That should increase continuous power above and beyond the factory performance.

[youtube]vJqrwCmpJ3A[/youtube]