# Motor "idle" power?



## DavidDymaxion (Dec 1, 2008)

Out of the car, my motor was about 250 Watts to spin it on 12 Volts. I haven't checked the clutch in / clutch out thing yet, I'll have to do that. I don't hear the motor slow at all clutch out, so I'd guess the difference is small. More info than you asked for: It take about 2.5 kW to drive neighborhood speeds on the flat, about 7.5 kW to climb the hills, and gives about 2.5 kW of regen down the same hills. That works out to be in the neighborhood of 100 Whr/mile, that's about right for 20 to 30 mph speeds. That's also done with a cold tranny, since I've only done 1 mile runs in cold weather so far, things will likely improve a bit with things all the way warmed up.


EVfun said:


> I was wondering how many watts it takes to run the motor in your EV when it is in neutral. How much does it take when you have released the clutch? How many amps is only useful if you give the pack voltage. What motor you have in your EV would be interesting to note as well.
> 
> I have been doing 12 volt tests on the ADC 8 inch motor in my Datsun. I'll post my test number later, after I get some other EVers input
> 
> Thanks!


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## EVfun (Mar 14, 2010)

I was hoping for a little more contribution. Thanks David for your assistance. 

My motor installed with the stock flywheel and old 4 speed Datsun gearbox (same one used in the Datsun Pickups) is 420 watts with the clutch pedal held down and 550 watts spinning the the gears. That works out to less than 5 amps from the pack once I install the it


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## Tesseract (Sep 27, 2008)

Hey EVfun... the Soliton1 generates reams of performance data while running and can idle the motor at a constant rpm to the p/s, a/c and torque converter (if applicable) happy. We have found - so far - that power consumed during idle varies quite a bit. 

I'm guessing, though, that you really want to see how much power it takes to keep the gears spinning inside the transmission even when it is in neutral. You need to compare that with the power consumed at the same RPM with the clutch pushed in to see how much of that power is attributable to the motor's losses and how much is in the tranny.

Worthwhile data to collect. Clarify what you are after here and I can do a few tests for you.


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## EVfun (Mar 14, 2010)

I am interested in the power required to spin the transmission in neutral, though at 130 watts I'm not too concerned about it. I'm mostly interested in learning how much power commonly used series motors require to spin at low rpms, as installed. My motor, installed and packing a heavy flywheel, needs around 420 watts (that includes the throwout bearing losses and I can hear that old bearing a little.) My transmission appears to require around 130 watts to spin with synthetic gear oil (Redline MTL.)


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## TheSGC (Nov 15, 2007)

I idle my automatic transmission and on a cold day it takes 576 watts and on a warm/hot day it takes 288 watts. On a freaking cold day you can hear the ATF slush around for a few minutes before warming up. My flywheel/TC is about 40 lbs filled up with ATF and the TC locks at 34 MPH.


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## Tom Thomson (Jun 11, 2008)

Hey EV fun
Why do you want to spin the gears if you're not going anywhere? Just curious.
tommyt


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## EVfun (Mar 14, 2010)

The alternative is testing everything all at once in the local traffic. That doesn't seem like a good idea. My style is to test every stage as I build so I can be confident when I wheel it into traffic the first time.


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