# Separately exicited controller question



## CPLTECH (Sep 14, 2007)

The 6.7”motor mentioned is rated at 10HP & motors are usually rated for their highest voltage, so de-rate if used at 48V. Also, to keep their cool, they love 3-4K RPM’s, not 1-3K.

A HP is 746 watts (VxA=W) .5KW is less than a HP, 3KW is 4HP, 10HP is 7.5KW.
So the question becomes, how much assist were you looking for? This forum has mentioned a few toasted motors of this small size. So watch that ammeter very, very closely & add a motor temp gauge. Why not consider a slightly larger unit.

I question the advisability of using regen. In my research, some tried it & burned up the brushes. For a benefit of maybe10% vs. motor repair, I say “no”.

If I might be so bold, sounds like you are trying to keep this conversion cost low. I can appreciate that, but is this setup going to meet your expectations? If so, go for it. Just do the precautions. 

Just my 2 cents worth. 94 S10 9” 26HP


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## Xringer (Oct 12, 2008)

CPLTECH said:


> The 6.7”motor mentioned is rated at 10HP & motors are usually rated for their highest voltage, so de-rate if used at 48V. Also, to keep their cool, they love 3-4K RPM’s, not 1-3K.
> 
> A HP is 746 watts (VxA=W) .5KW is less than a HP, 3KW is 4HP, 10HP is 7.5KW.
> So the question becomes, how much assist were you looking for? This forum has mentioned a few toasted motors of this small size. So watch that ammeter very, very closely & add a motor temp gauge. Why not consider a slightly larger unit.
> ...



Okay, I can understand that. If I ever had the need for max rated HP, I'll need to be using the max voltage it's rated for. 
The need for lower RPMs is a sticking point.

This little peanut motor can make a couple of HP down at the lower RPMs..
http://www.electricvehiclesusa.com/product_p/mo-es-80a.htm
Just need to use less voltage.. Or will the PWM @48v allow for 2.3HP at 1830 RPM without smoking anything??


Since this this is_ *weak *_hybrid project, the regen needs to be working.
I'll need (want) the ability to charge the pack while driving unassisted
(in full ICE mode). 

Yeah, I'm trying to do this cheaply. I see that a basic motorcycle sized controller and motor can be had for about $1000. 
So, there is a possibility that a few hp of ICE assist could be added to a Gen1 Honda CRV for under $2000. 
If those few hp could increase the MPG significantly, it just might be worth it. If not, I could always start looking for a dead motorcycle.


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## Guest (Oct 29, 2008)

Kelly has a nice 72 volt controller and 600 amp SepEx controller. Regen too. 

Pete : )



Xringer said:


> I'm looking at this type of controller:
> http://www.electricvehiclesusa.com/product_p/co-kd72203.htm
> Kelly 24-72 Volt 200amp Separately Excited w/ Regen
> 
> ...


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## Xringer (Oct 12, 2008)

gottdi said:


> Kelly has a nice 72 volt controller and 600 amp SepEx controller. Regen too.
> 
> Pete : )


I may end up using a 40 to 60 AH pack and a motor with less than a 10kw peak, so I shouldn't need such a high powered controller.


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## CPLTECH (Sep 14, 2007)

CPLTECH said:


> I question the advisability of using regen. In my research, some tried it & burned up the brushes. For a benefit of maybe10% vs. motor repair, I say “no”.
> 
> From the WIKI section...
> *http://www.diyelectriccar.com/forums/showthread.php?t=8848*
> ...


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## frodus (Apr 12, 2008)

Xringer said:


> I'm looking at this type of controller:
> http://www.electricvehiclesusa.com/product_p/co-kd72203.htm
> Kelly 24-72 Volt 200amp Separately Excited w/ Regen
> 
> ...


Won't work. Sepex controllers do not work with series wound motors. That is not a sepex motor, it was the series motor I almost used (I ended up using a K91-4003)

HOWEVER, D&D does make two sepex motors that I know of in the same size as that ES-15A (ADC K91-4003):

ES-32A-50
72 volt
3600 rpm
Ia= 105
If=8.0
8.3 HP Cont

ES-89-14
72 volt
3500 rpm
Ia=80
If=12.0
6.5HP Cont

Sepex motor and controller packages start around $1200 for something that you'd be able to use.


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## Guest (Oct 30, 2008)

I use a Kelly KD-72605 Special SepEx controller designed for the old military starter/generator motors with interpoles. These are SepEx motors and are designed and timed for traction and regen. The modern controller is the next logic step for these fine motors and these motors are high rpm motors up to 8000 rpm. Screaming fast. Not so with your standard series motors. The Kelly Controller also includes field weakening so with the lower voltage set up the motor can be run faster when at speed with less power requirements. I get regen too. Oh, I said that already? Dooh! If you have a series motor with interpoles and have it timed right you can use a series for regen. I would not use regen if you do not have interpoles and don't have it timed for regen. 

Pete : )


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## Guest (Oct 30, 2008)

We may upgrade to a 120v SepEx and see how this motor can handle the power. We may not. These motors are built to last a long time. I'd love to see what we can do with one of them. Not for sure but maybe we will.


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## Xringer (Oct 12, 2008)

frodus said:


> Won't work. Sepex controllers do not work with series wound motors. That is not a sepex motor, it was the series motor I almost used (I ended up using a K91-4003)
> 
> HOWEVER, D&D does make two sepex motors that I know of in the same size as that ES-15A (ADC K91-4003):
> 
> ...


My mistake. I meant to pick out a Sepex motor to use in my example.
Since Sepex has regen without the generated reluctance loading when free-wheeling (I hope).

It would be nice to find a website with those two motors shown with some good specs & prices..


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## Xringer (Oct 12, 2008)

CPLTECH said:


> CPLTECH said:
> 
> 
> > I question the advisability of using regen. In my research, some tried it & burned up the brushes. For a benefit of maybe10% vs. motor repair, I say “no”.
> ...


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## JRP3 (Mar 7, 2008)

You might want to look at an Alltrax controller. They've been doing controllers for a lot longer than Kelly and have a better reputation. Alltrax controllers and D&D motors can be had here:
http://evdrives.com/index.html
Be sure to check out the newest featured vehicle there as well


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## Xringer (Oct 12, 2008)

JRP3 said:


> You might want to look at an Alltrax controller. They've been doing controllers for a lot longer than Kelly and have a better reputation. Alltrax controllers and D&D motors can be had here:
> http://evdrives.com/index.html
> Be sure to check out the newest featured vehicle there as well


I looked over their DCX controllers (with re-gen) and the config software.
http://www.alltraxinc.com/Products_DCX.html

They don't seem to have any analog input to control regenerative braking. Just a max setting in the software. 

I was looking at the Kelly controllers, because the Kelly SepEx controller has pins for connecting a throttle-like pot for precise regen current control. (In addition to the Max current software setting). 

The Kelly SepEx controller seems like it would a good one for my application. 
I should expand the name from Weak Hybrid, to Weak plug-in Hybrid.

The car would start off each day with a good SOC and the goal would be
to *use all the available *KWHs in the pack within xx miles.
That xx mile number would be adjustable from 5 to ~20 miles.

The two regen goals would be:
1. Turn on regen when MPG was higher than normal. (Automatically ?). 
2. Manually control regen amps in case of low SOC during long trips.
(with no grid hookup in sight)


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## JRP3 (Mar 7, 2008)

Xringer said:


> I looked over their DCX controllers (with re-gen) and the config software.
> http://www.alltraxinc.com/Products_DCX.html
> 
> They don't seem to have any analog input to control regenerative braking. Just a max setting in the software.


It looks to me as if there is a slider for regen from 0-100% in the software, "brake current", but the only way to adjust it is with a PC hooked up, and I don't know if it allows on the fly adjustment. 
http://www.alltraxinc.com/images/Controller-Pro-Screen-Control.gif
Even with full regen you only get back maybe 10%, would you really need to adjust that lower?


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## Xringer (Oct 12, 2008)

JRP3 said:


> It looks to me as if there is a slider for regen from 0-100% in the software, "brake current", but the only way to adjust it is with a PC hooked up, and I don't know if it allows on the fly adjustment.
> http://www.alltraxinc.com/images/Controller-Pro-Screen-Control.gif
> Even with full regen you only get back maybe 10%, would you really need to adjust that lower?



That 10% number seems awfully low.. Regular hybrid cars that don't plug-in to the grid are using _*regen*_ & the _*ICE *_for 100% of their recharging needs.

Ideally, my weak-plug-in-hybrid would mimic the Honda Insight system of
getting better MPG..


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## JRP3 (Mar 7, 2008)

Xringer said:


> That 10% number seems awfully low.. Regular hybrid cars that don't plug-in to the grid are using _*regen*_ & the _*ICE *_for 100% of their recharging needs.


Yes, and the ICE is probably providing providing 90% of the charging. Hybrids don't get much of their efficiency from regen.


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## Xringer (Oct 12, 2008)

JRP3 said:


> Yes, and the ICE is probably providing providing 90% of the charging. Hybrids don't get much of their efficiency from regen.


I really don't know.








What's that say? 50 watt hours? Not much..
Regardless of how they do it, they sure can get some good MPG..
Maybe some Prius owners could post what they are seeing for regen.?.


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## frodus (Apr 12, 2008)

JRP3 said:


> Yes, and the ICE is probably providing providing 90% of the charging. Hybrids don't get much of their efficiency from regen.


I agree 100%

regen can capture 10 MAYBE 15% energy back from braking.... But its free. It'd be heat otherwise.


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## Xringer (Oct 12, 2008)

frodus said:


> I agree 100%
> 
> regen can capture 10 MAYBE 15% energy back from braking.... But its free. It'd be heat otherwise.


How about coasting?? 
There are a few hills around here about a mile long. I leave my CRV in 5th
and the ICE braking slows me down. BUT, I still have to step on the brake petal a bit, to avoid speeding. (or downshift).

During the coast, the ICE goes into fuel-cut-off mode and the SG2 shows 999.9 MPG.. 

It's times like that when I start thinking that a regen joystick might be useful.


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## frodus (Apr 12, 2008)

well, there's a difference in % back from regen and total Wh back from regen. Wh can increase quite a bit, but % means how much you convert from mechanical to electrical. Its not that efficient.

50Wh isn't that much... it'd take a 500Wh pack 10 hours to recharge.


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## Xringer (Oct 12, 2008)

frodus said:


> well, there's a difference in % back from regen and total Wh back from regen. Wh can increase quite a bit, but % means how much you convert from mechanical to electrical. Its not that efficient.
> 
> 50Wh isn't that much... it'd take a 500Wh pack 10 hours to recharge.



Humm, 50WH=180,000 Watt seconds. So, if you needed an extra 18KW of power for about 10 seconds to get across a busy intersection. Maybe a *free *50Wh would be nice to have, to back up your ICE..


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## frodus (Apr 12, 2008)

but it doesn't do a ton for range.


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## Xringer (Oct 12, 2008)

frodus said:


> but it doesn't do a ton for range.


Every little bit helps.. 

Because I want to the assist system to be light weight, I'm not going
to have much assist range in the pack. 

It will be designed to use all the available power within about 10 miles.
At 30 MPH, that's ~20 minutes of run time. 

The amount of ICE assist is going to depend on the pack..


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## frodus (Apr 12, 2008)

you'll have to account for the electrical load that the batteries have on the motor. Generators don't spin freely when connected to a large load. Also, there's the weight of the motor/batteries as well as the spinning resistance of the motor/brushes to consider.

Not saying it won't help... but they're things to consider when designing.


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## Xringer (Oct 12, 2008)

frodus said:


> you'll have to account for the electrical load that the batteries have on the motor. Generators don't spin freely when connected to a large load. Also, there's the weight of the motor/batteries as well as the spinning resistance of the motor/brushes to consider.
> 
> Not saying it won't help... but they're things to consider when designing.



Yeah I know what you mean about the load of the pack. But the info I've seen 
on controllers seems to show they can be preset to a max regen current level.
The safe charge rate of the pack is going to be one limiting factor.
And the other factor will be the *braking effect*. Starting off, I would like to control 
the braking effect with a joystick to get a feel of what the braking is like.

I plan to try keeping the motor weight under 40 pounds if possible.
My goal for the pack may be about 200-300 pounds. 
I've already removed about 130 pounds from the rear end (the rear wheel drive parts) 
and will try not to put back more than 20-30 pounds with the motor mount and coupling hardware.


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## frodus (Apr 12, 2008)

Xringer said:


> Yeah I know what you mean about the load of the pack. But the info I've seen
> on controllers seems to show they can be preset to a max regen current level.
> The safe charge rate of the pack is going to be one limiting factor.
> And the other factor will be the *braking effect*. Starting off, I would like to control
> ...


40lb motor, thats kinda small for a car... I know its assist....but also realize, you're not going through a transmission, so there's only the rear diff for gear reduction, so its going to need more torque to really be that helpful.


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## Xringer (Oct 12, 2008)

frodus said:


> 40lb motor, thats kinda small for a car... I know its assist....but also realize, you're not going through a transmission, so there's only the rear diff for gear reduction, so its going to need more torque to really be that helpful.


 I'm looking for something in the weight & power range of the Mars ME-0709 PM motor, but that works well at low RPMs.. That may not be possible within my budget.. Since my drive shaft (Propeller) is not too heavy, I was thinking of using it to apply power back into the engine via the transfer case. Positioning the motor back where the old rear diff used to sit..







video of transfer case rotating. http://s46.photobucket.com/albums/f147/Xringer/CRV/?action=view&current=M104.flv The motor would sit right here..







Taking the place of this old rear diff.. (Which is in storage now).


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## frodus (Apr 12, 2008)

doesn't your vehicle have 3 diffs? one for front, one for rear and another one for the front/rear? Are you just going to "stop" the f/r diff from spinning? or let it free spin?

I think mechanically its not going to work, can you explain a little bit more?


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## Xringer (Oct 12, 2008)

frodus said:


> doesn't your vehicle have 3 diffs? one for front, one for rear and another one for the front/rear? Are you just going to "stop" the f/r diff from spinning? or let it free spin?
> 
> I think mechanically its not going to work, can you explain a little bit more?


 The rear wheel short axles (& CV joints), main drive (propeller) shaft & rear diff are gone. The rear wheels are free wheeling now. What I would like to do is re-install the main drive shaft propeller and add a motor back where the rear diff used to be..







The main problem I see is, at 60 MPH the transfer case is only turning at 1900 RPMs..


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## frodus (Apr 12, 2008)

So how does the front transmission function? I mean, can you put it in FWD only? It seems like the shaft that used to go to the rear diff would spin freely and you wouldn't go anywhere.


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## Xringer (Oct 12, 2008)

frodus said:


> So how does the front transmission function? I mean, can you put it in FWD only? It seems like the shaft that used to go to the rear diff would spin freely and you wouldn't go anywhere.


 http://s46.photobucket.com/albums/f147/Xringer/CRV/?action=view&current=M104.flv With the rear end RTAWD parts removed, it's a plain old FWD with a 5 speed tranny. The front diff is directly connected to the transfer case. When the front wheels turn, so does the transfer case output. If you ever drive behind a CRV, you can look under and see the drive shaft spinning all the time. In 4WD mode, the rear wheels are engaged by a special clutch inside the rear diff.


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## frodus (Apr 12, 2008)

Oh, so there's just a front and rear diff, with no front/rear diff. I wasn't sure how it distributed power, some cars have 3. Totally understand now. Thanks for the video.

One thing you might consider, is keeping the rear diff, and coupling it to the motor.

or couple it and keep the RWD, and use the EMIS

http://www.electric-cars-are-for-girls.com/hybrid-cars.html
http://www.go-ev.com/EMIS-Desc.html


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## Jimdear2 (Oct 12, 2008)

Xringer said:


> The rear wheel short axles (& CV joints), main drive (propeller) shaft & rear diff are gone. The rear wheels are free wheeling now. What I would like to do is re-install the main drive shaft propeller and add a motor back where the rear diff used to be.. The main problem I see is, at 60 MPH the transfer case is only turning at 1900 RPMs..


A FYI;
The AWD right angle drive unit that replaces the stub axle normally installed on FWD only vehicles is generally called a Power Take Off Unit (PTU). It is directly connected to the Transaxle's differential side gear and will turn and react directly with the front axle on that side of the vehicle. These units rarely have any form of internal disconnect.

A possible solution to your shaft RPM problem woud be a 2 to 1 gear reduction unit on the front of the motor. Your motor supplier/builder may be able to directly connect you to a supplier for a unit designed to mount on the motor.

Otherwise go to McMaster-Carr look under steel gears. Using those gears.
A good machinist should be able to to build you a gearbox for about the price you would pay for a custom motor adapter plate. We used two of these gears (5 inch dia.) to couple two 120 HP motorcycle engines together in a pulling tractor. It has never broken in 5 years of pulling. We did have the gear teeth hardened. The 3 inch gear on the motor shaft and a 6 inch on the output shaft look prommising.


Hope this helps
Jim


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## frodus (Apr 12, 2008)

Here's a ton of gearboxes.... all sorts of ratios. C-face mount (6.7" face) too!

http://surpluscenter.com/powerTrans.asp?UID=2008110518102411&catname=powerTrans


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## Xringer (Oct 12, 2008)

frodus said:


> Oh, so there's just a front and rear diff, with no front/rear diff. I wasn't sure how it distributed power, some cars have 3. Totally understand now. Thanks for the video.
> 
> One thing you might consider, is keeping the rear diff, and coupling it to the motor.
> 
> ...


 I have considered keeping the rear diff and driving the rear wheels, since there is a clutch system inside the diff that would (I think) disengage when the e motor dropped below a certain RPM. (wheel RPM * 2.533). Since I would still need 1900 motor RPMs @60MPH, I would need to add a gearbox or use a low RPM motor.. However, the rear diff is a big load on the engine, so I would need to use a Larger motor than I really want. And the pack would need to be larger too. And the diff & shafts would add around 100 pounds itself. I want to keep it light and simple as possible.


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## Xringer (Oct 12, 2008)

Jimdear2 said:


> A FYI;
> The AWD right angle drive unit that replaces the stub axle normally installed on FWD only vehicles is generally called a Power Take Off Unit (PTU). It is directly connected to the Transaxle's differential side gear and will turn and react directly with the front axle on that side of the vehicle. These units rarely have any form of internal disconnect.
> 
> A possible solution to your shaft RPM problem woud be a 2 to 1 gear reduction unit on the front of the motor. Your motor supplier/builder may be able to directly connect you to a supplier for a unit designed to mount on the motor.
> ...


 IF, I could use direct connect and skip the gear boxes etc, that would make things so much simpler. Here are some plots of the Mars 0709 PM motor that I've been looking at. http://www.evdrives.com/Manuals/Mars_Electric/ME0709 Performane Data.pdf Maybe I'm wrong in my interpretation, but this motor seems like it might perform pretty well in the 1000 to 2000 RPM range. It seems to be a good motor for motorcycle conversions.. Maybe it would be ok assisting a little 2L Honda engine. I realize it won't be running a lot of HP, but I won't have a big pack anyways. I just want a small assist for the ICE. What do you guys think of it? Thanks!


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## JRP3 (Mar 7, 2008)

That will be a very small assist for the ICE. Since you aren't using a gear box this motor will be under heavy load at low RPMs, the opposite of what you want to preserve the life of a motor.


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## Xringer (Oct 12, 2008)

JRP3 said:


> That will be a very small assist for the ICE. Since you aren't using a gear box this motor will be under heavy load at low RPMs, the opposite of what you want to preserve the life of a motor.


I would have to really limit the amps at low speeds. It would likely work best if turned on after the car gets up some speed.

Installing a gear box will mean some extra drag when off and maybe getting more regen rpms than I want.. 

If I had a gear box or belts, using a clutch would be good.
Like on an AC compressor..


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## JRP3 (Mar 7, 2008)

Xringer said:


> I would have to really limit the amps at low speeds. It would likely work best if turned on after the car gets up some speed.


Which is exactly the opposite of what you want in a hybrid. Most hybrids get a good boost by using the ev motor to get the vehicle moving where the ICE is less efficient and the torque of the ev motor is highest. I have a feeling you may be doing a lot of work for very little benefit in the end.


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## Xringer (Oct 12, 2008)

JRP3 said:


> Which is exactly the opposite of what you want in a hybrid. Most hybrids get a good boost by using the ev motor to get the vehicle moving where the ICE is less efficient and the torque of the ev motor is highest. I have a feeling you may be doing a lot of work for very little benefit in the end.



There could still be some benefits when driving around town above 30 MPH and for short trips down I-95 etc. 
Especially when going up long hills at 55 MPH (cruise control) and the fe drops off to less than 20 MPG for 30 or 40 seconds. 

After seeing how hub motors work, I know it must be possible to get some low RPM E-power.. Somehow! 

When I saw this site, I was encouraged. 
http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac-induction.php

But, there is some question about how well the motors listed actually perform. (Not much documentation around).


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## frodus (Apr 12, 2008)

Xringer said:


> There could still be some benefits when driving around town above 30 MPH and for short trips down I-95 etc.
> Especially when going up long hills at 55 MPH (cruise control) and the fe drops off to less than 20 MPG for 30 or 40 seconds.


Not if you're not geared right, you'll be sucking amps out of the motor, controller and batteries. Its extremely inefficient for motors at low RPM, almost Always. Look at the torque curves, the RPM's are much higher for the higher efficiencies. You NEED a gearbox.

Also, consider this, If you DON'T uncouple the motor somehow, what happens when you go 70? you spin that motor apart. You need a balance of low RPM torque and ability to go to the max RPM at say 70mph.

That motor is way too small for what you're trying to do, especially without a gearbox. Motorcycle guys use a 6:1 gear ratio between motor RPM to wheel RPM. Even then, we might go 5000RPM max and get 60mph out of it.


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## Xringer (Oct 12, 2008)

frodus said:


> Not if you're not geared right, you'll be sucking amps out of the motor, controller and batteries. Its extremely inefficient for motors at low RPM, almost Always. Look at the torque curves, the RPM's are much higher for the higher efficiencies. You NEED a gearbox.
> 
> Also, consider this, If you DON'T uncouple the motor somehow, what happens when you go 70? you spin that motor apart. You need a balance of low RPM torque and ability to go to the max RPM at say 70mph.
> 
> That motor is way too small for what you're trying to do, especially without a gearbox. Motorcycle guys use a 6:1 gear ratio between motor RPM to wheel RPM. Even then, we might go 5000RPM max and get 60mph out of it.


Looking at these plots http://www.evdrives.com/Manuals/Mars_Electric/ME0709%20Performane%20Data.pdf 
I'm not 100% sure that I understand them correctly, but it seems like they would work okay between 1000 and 2000 RPMs. 

With the size tire I'm using and the transfer case output being 2.535 * each tire rotation, it seems like 30 MPH would be 971 RPM, 60 MPH would be 1941 RPM and 80 MPH would be 2589 RPM. 
So, I don't think there is any danger of over-speeding the motor.
(I never drive over 75 anyways). 

With a 72V pack, the Mars 0709 should get up to 2600 RPM easily..

Even if it's running with low efficiencies around town at 30 MPH, every
bit of help it gives to the ICE is almost free. (well 20 cents KWH).

After 5 miles and the pack is getting low, I could steal 60 watts off the ICE using regen mode to start the pack charging again, 
for that big hill when I'm heading home.


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