# Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...*

I am also wondering about the lockup point of the torque
converter - I'd expect that it would be no higher than at
2300 RPM, because that is 55 MPH in Overdrive.

You have given me a clue why I am burning so much of my
power in the transmission - it may not be the best to
keep my motor at or over 4000 RPM the whole drive home,
it could lower the loss in the transmission if it is
switched to higher gear once I reach freeway speed.
So, I will test the current draw at different gear
settings to maintain the same speed and figure out
how to avoid burning almost half my energy in the
transmission.

I will also ask for advice from a friend about removing
the transmission completely and simply run direct drive
which should result in a good efficiency improvement,
but might be not as easy as I think about - simply
removing the entire transmission and extending the drive
shaft.
The drawback is loss of torque (again) at lower speeds 
though I still need to check the motor current limiting
as I never see the battery amps go much over 300A so
I am guessing that the new shunt that I put in with the
new IGBTs might be a higher resistance than stock,
causing the motor not to receive full amps from the
controller.
I expect that an 11 inch GE motor can be fed more than
300A.
Maybe in further future a Lithium upgrade is a good
thing - will reduce weight and improve acceleration
as well as giving a stiffer pack so power stays higher
and we have the double whammy effect.
Still I will look into efficiency improvements, so
thanks for the discussion and the suggestions!

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Morgan LaMoore
Sent: Saturday, June 23, 2012 5:07 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Transmission is getting hot (motor too) and I use
toomuch power...

I wonder if the torque converter isn't locking up and is burning up lots
of power. 4000 RPMs in second gear would be heavy acceleration with an
ICE and wouldn't be a nice, efficient, low-reduction or locked operating
mode. If the losses are based on RPMs more than torque, an extra 10-15kW
of losses while accelerating hard wouldn't be a big deal like it is
while cruising.

Also, is the transmission oil pump pumping at a higher rate/pressure at
higher RPMs? Is some of the energy being transferred to the transmission
lubricant then being dissipated as heat?

-Morgan LaMoore

On Sat, Jun 23, 2012 at 2:35 AM, Cor van de Water <[email protected]>


> wrote:
> 
> > Apologies in advance for the long post, but instead of asking a short
> > question and then subsequently posting the info after each of you ask
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...*

Something else to throw into the mix is the S-10 is significantly more aerodynamic than the Ford, so aero drag might be part of your power loss. The GM Factory S-10 electric had just a 0.34 Cd, and the gassers had ~10 to 20% better aero than the Ford Ranger.
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...*

Have you checked the possibility of manually energizing the converter lock-up
solenoid?

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...*



> Cor van de Water wrote:
> 
> > What RMP do you suggest that the torque converter should
> > (dis)engage? 2000 RPM?
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Transmission is getting hot (motor too) and I use toomuch power...*

I like the idea of mounting the motor in the driveshaft tunnel. That frees 
up more underhood space for batteries, to improve weight balance.

It would mean a lot of fabrication work, but if you have access to the 
necessary facilities, that sounds like a good plan.

Another approach would be to fit a manual transmission. If you lock it in 
gear (second or third?) as USE did with their car conversions, you'd avoid 
the hassle of a clutch and shifter. 

David Roden - Akron, Ohio, USA
EVDL Administrator

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