Quote:
Originally Posted by BrianG
jhautz: why you get less runtime with motor braking is still puzzling to me. Without a consistent and repeatable test method, results are simply objective. Not trying to shoot ya down, just my $0.02.
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I hear ya, but thats just about as consistent and repeatable as I will be able to get in a real world test. This is something that I just observed when I went from mechanical brakes to motor brakes in my truggy. I was trying to just simplify the system as the mechanical brakes werent giving me any lap time benefits on the high traction indoor track. So when I took the mechanicals off I noticed I used a little more mah. I wanted to understnad what was happening. it could have been differences in the track layout or the traction from one day to the next so I did my little experiment to try and eliminate all of the other variables except the mechanical/motor brake difference. What I saw confirmed my suspision. Not a highly scientific or overly controlled experiment, but the results were clear enough that I am assuming what I am seeing is real.
I'm not arguing that regen braking isnt happening, I'm just wanting to understand if it means anything at all to the runtime. my suspision is that the motor brakes take energy to work. Of course... I have no real proof of that except for my little experiment and what I personally have observed.
I didnt mean to totally derail your thread Brian, but at this point I do hope that we get some input from someone who truely understands this all. I had the same discussion with Mike and we didnt come up with a real answer either.
FYI: I went and found my notes from my test. I know its not a huge sample size or a super controlled test but it seems like pretty simple clear result to me. I dont think I would have the time to put together something that would be statistically significant and completely controlled. Its enough to convice me personally.
Setup was:
RC8T, 1515/2.5D, MMM, 5s lipo, 15/50 gearing.
Lipo Pack #1 was a 5s 4300mah Neuenergy 25c
Lipo pack #2 was a 5s 5000mah Zippy Flightmax 30C
Track was a medium/small sized track. (125ft x 75ft with a 100ft straight) indoor high traction clay surface with alot of quick burst straights and sharp 180 corners. The layout required alot of braking to get around it quickly.
mah usage on a 5 minute run with mechanical brakes:
Pack #1 =1122mah Pack #2 =1146mah
mah usage on a 5 minute run with motor brakes:
Pack#1 =1241mah Pack #2 =1296mah
Pack #1 results 1241-1122=119 119/1122= 10.6% increase in mah used with the motor brakes.
Pack #2 results 1296-1146=150 150/1146= 13.1% increase in mah used with motor brakes.