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Is there a way to accurately calculate actual motor amp draw during a race? My class is 1/10 scale oval, 6 cell Trinity SPEC battery and 21 turn SPEC motor. Thanks for the help.

Ron
 

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Ron,
Yes, there is a way. First, you need to cycle your pack on a CE Turbo 30 (Or 35) and record the runtime. (I would discharge at atleast 30 amps).
Then, after the completion of your next race, discharge the remaining capacity of the battery. Now you have all the data you need to calculate average amp draw for your car that race.

Say you had a pack that cyled 400 seconds at 30 amps, and after a 5 minute race, (300 seconds) you had 90 seconds left at 30 amps.
Here is the equation:
Pack runtime minus remaining runtime equals capacity used. Divide capacity used by pack runtime and you will get a percentage. Divide that percentage by the discharge amp rate and you will have an average amp draw for your race:

400-90 = 310
310 divided by 400 = .775
.775 x 30 = 23.25
Your average amp draw for that race was 23.25 amps.

This can obviously fluctuate with different motors, gearing, driving style, number of wrecks, chassis setup, etc;

Hope this helps...:thumbsup:
 

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Formula???

Todd,
If the battery is used up in 390 seconds (300 seconds of racing and 90 seconds @30 amps remaining) and the battery is capable of 400 seconds @30 amps, then more than a 30 amp average was used during the race. I believe the formula is as follows:
400-90=310
310/300=1.03333333
1.03333333 X 30=31 amps
:confused:
 

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7334otdortoh, you are correct, tp must have dropped his calculator. i view it as this way.

400s * 30A = 12000 As (amp-seconds total availiable in the pack)
90s * 30A = 2700 As (amp-seconds left after the run)
12000As - 2700As = 9300 As (amp-seconds used during the run)
9300As / 300s (race length = 5min = 300s) = 31A average usage during the race.
 

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You are correct; My thoughts didn't make it from the top to the equation posted...
Harrington: that's why we pay you the big bucks...:thumbsup:
 

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Oh man your making my head spin, bring me another beer. :drunk:
 

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We used some om board telemetry, amp draw was lower than we thought, out of tight corners was 22-25 amps, less down the straights, the better the car was handling the lower the overall amp draw. Amp draw really spikes when you tap the wall or another car.
 
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