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Old 12-08-2009, 12:06 AM   #1
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Default What size mah lipo gives best punch/power?

Just getting into indoor touring, running a JRXS-R with Tekin RS Seems like the fast guys run like a 3600 mah battery, others run a 5000mah. All are around a 40C. I've heard the small mah batteries warm up quicker and generate better "punch". The larger batteries don't warm up quickly enough in a 5 minute heat or 8 minute main.

Is there any truth to this? Which size battery/C rating will give me the most punch and power?

Thanks guys.
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Old 12-08-2009, 07:17 AM   #2
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Let me show you about my problem, in fact i have also the same troublesome, but until now the answer is so uncleared and with many unknowns, then, just to judge by yourself about my story .

In our 3100KV 8min class, the guys which run in the front are using 4200 of GE power and BY energy, they tell me runnning with low capacity lipo in spec class is better than run with high capacity lipo. But in the last sunday, i saw many of them have finished their battery in earlier 7 min during qual. session.

Then i saw another guy which run in 4000KV class, he brought another car with 3000KV motor to make a test in the track. He ran with that 3000KV car with IP3800, IP5000 and Orion carbon molecular 5000 battery, then he tell me the 5000's have more punch than 3800 in that car. And i asked him about if really "low capacity batteries fits in 3000KV motors", he said me that he didn't hear this kind before, he just said me that you need to test it by yourself, which he really did.
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Old 12-08-2009, 08:16 AM   #3
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Sounds like there may be some confusion on this topic, glad I posted it. Anyone else have an opinion or advice?

Thanks!
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Old 12-08-2009, 08:40 AM   #4
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Higher mah "should" give better power due to the voltage staying higher for longer. Of course that only applies if all other factors are equal (which of course they are not). Some batteries are just made better than others. This is why some companies cycle test large groups of packs and only keep the best ones. Of course you have to pay extra for them...
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Old 12-08-2009, 08:53 AM   #5
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Here is an easy formula for you to follow:
mah x C rating = amps
Amps translates to torque (punch).
So for example:
5000mah 20c lipo will have 100amps (5 x 20 = 100)
Where a 4000mah 30c will have 120amps (4 x 30 = 120)

What you have to do is figure out the max continuous amperage your esc and motor need, and go from there.

You said that they are running a 3600 40c (144amps) and a 5000 40c (200amps). My logical guess here would be the the guys running the 3600s are lighter.

Edit: Another big factor in punch would be gearing.
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Old 12-09-2009, 08:24 AM   #6
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Quote:
Originally Posted by portyansky View Post
Here is an easy formula for you to follow:
mah x C rating = amps
Amps translates to torque (punch).
So for example:
5000mah 20c lipo will have 100amps (5 x 20 = 100)
Where a 4000mah 30c will have 120amps (4 x 30 = 120)

What you have to do is figure out the max continuous amperage your esc and motor need, and go from there.

You said that they are running a 3600 40c (144amps) and a 5000 40c (200amps). My logical guess here would be the the guys running the 3600s are lighter.

Edit: Another big factor in punch would be gearing.
Cool, good info. We have a minimum weight limit so even if the the batteries were lighter they would have to add weight to stay legal.

Any other opinions?
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Old 12-09-2009, 08:52 AM   #7
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Quote:
Originally Posted by portyansky View Post
Here is an easy formula for you to follow:
mah x C rating = amps
Amps translates to torque (punch).
So for example:
5000mah 20c lipo will have 100amps (5 x 20 = 100)
Where a 4000mah 30c will have 120amps (4 x 30 = 120)

What you have to do is figure out the max continuous amperage your esc and motor need, and go from there.

You said that they are running a 3600 40c (144amps) and a 5000 40c (200amps). My logical guess here would be the the guys running the 3600s are lighter.

Edit: Another big factor in punch would be gearing.
No 1/10th scale is capable of pulling anywhere near 100amps continuous. At top level mod touring car, the highest would be 35 to 40amps. If you were to run a 40C lipo at an actual 40C discharge rate, you would dump the entire pack in less than 1.5 minutes (no matter the capaicty). That just isn't possible on the track. For this reason, there is just no longer a need to worry about buying higher C ratings.

The 5000mah 20C will hold it's voltage higher and longer than the 4000mah 30C. The higher the voltage, the more current the motor will draw and the more power & torque you will have for longer in the race. Remember, it's up to the motor to draw current. The battery cannot push it. Higher voltage = more current...
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Old 12-09-2009, 10:59 AM   #8
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Quote:
Originally Posted by 94eg! View Post
No 1/10th scale is capable of pulling anywhere near 100amps continuous. At top level mod touring car, the highest would be 35 to 40amps. If you were to run a 40C lipo at an actual 40C discharge rate, you would dump the entire pack in less than 1.5 minutes (no matter the capaicty). That just isn't possible on the track. For this reason, there is just no longer a need to worry about buying higher C ratings.

The 5000mah 20C will hold it's voltage higher and longer than the 4000mah 30C. The higher the voltage, the more current the motor will draw and the more power & torque you will have for longer in the race. Remember, it's up to the motor to draw current. The battery cannot push it. Higher voltage = more current...
excellent info there.
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Old 12-09-2009, 11:03 AM   #9
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Quote:
Originally Posted by CBR1000RR View Post
Cool, good info. We have a minimum weight limit so even if the the batteries were lighter they would have to add weight to stay legal.

Any other opinions?
Being a good driver helps a lot(not saying you're not bc i don't know you ). Proper throttle control, gearing, and even playing with motor timming.
The other biggesr advice is to ask the fast guys what they are doing. Most will tell you.
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Old 12-09-2009, 01:29 PM   #10
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The internal resistance of the battery has more effect on "punch" than the continuous C rating, just like with NiMH batteries. The lower the IR, the more "punch" the pack will have. The higher capacity packs generally provide a higher average voltage (over the normal race duration) since you are using a lower percentage of the capacity.

Think of a V8 with a lot of torque vs. a 4 cylinder that revs high. Even though the peak HP may be the same, the big V8 probably has more torque, so it jumps off the line, vs having to rev the heck out of the 4 banger to get decent output.
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Old 12-09-2009, 06:35 PM   #11
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i have tested a few battery packs of different brands, Cs and capacities and "conventional wisdom" about high C packs are often not true.....

i have a 5000mah 30c pack that holds more oomph than a 5000mah 45C of another brand... within the same brand, it also beats a 5000mah 40C... so not all lipos are made the same and C ratings might not be accurate...

in short, buy high capacity packs from reliable brands and just be more concerned about your driving... forget abt splurging more for that extra 5 or 10Cs..... at least my slow fingers cant feel it....
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Old 12-10-2009, 09:05 AM   #12
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My experience is the higher the mAh the better, even with a 10.5BL. I run a 10.5T LRP X11 and spx stock spec ESC. Using a Trakpower 3600mAh 30C battery (with about 100 charge cycles on it). I noticed voltage dips down to around 6.8V (using a a Novak Sentry datalogger) during accleration. The motor was pulling 45Amps, but battery is theoretically able to supply 108 Amps....

I replaced the battery with a new Trakpower 5000mAh 40C Darkpower series battery and the car is transformed - voltage drop is negligible (down to 8.2V), and keeps the voltage more constant during the race. Acceleration is MUCH improved, far outweighing the increased weight of the battery. Obviously the battery is new, but the old 3600mAh was still well within capacity and number of charge cycle limits.

I think this is down to the low internal resistance of the higher capacity battery rather than capacity or "C" rating as such. Also bear in mind that "C" ratings are not a regulated measure, so one is at the mercy of manufacturer claims. Trakpower is a well known, reputed brand tho!

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Old 12-10-2009, 09:13 AM   #13
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Don't forget that the C ratings on the battery are the *continuous* current ratings. Generally, most LiPos can provide 2x the continuous current rating for something like 10 second bursts. So your 30C rated pack can provide 60C for short bursts.
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Old 06-24-2011, 02:57 PM   #14
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im trying to figure out which size i should use. 4400 or 6000. its going in a basher so would the 6000 be better?
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Old 06-24-2011, 04:56 PM   #15
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+1 to most of the guys posting here. Higher capacity keeps the voltage up for longer. My previous 4200mah started dropping in power after 4 minutes, where as 5300mah stayed more consistent (fast) through the entire run.
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