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How high of Mah to go?

Old 04-29-2014, 10:29 PM
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Default How high of Mah to go?

So i have an HPI sprint 2 with a sidewinder v2, and a 3300kv motor, im looking to run some 3s lipos in it, i already ran it with a 2600mah 3s not sure the cc and it haled ass. But im looking to get some more bigger faster batteries and not fry anything.
Old 05-02-2014, 12:17 PM
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bump, I know some say 3s is high but its on a road car with low Kv So i think it will be fine,
Old 05-02-2014, 03:19 PM
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Regarding the mAh you can go almost as high as you want, as long as the battery physically fits in your car. As for the C-rating i don't quite know, but maybe in the 40-50 area will be enough?
Old 05-02-2014, 04:00 PM
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The c rating is the discharge rate, so for example some lipo batteries say 25c 30c or 45c.. The higher the number the better the power transfer and flow is from the cells to whatever it is powering. My lipo is a 7.4v 4500 45c
Old 05-02-2014, 10:26 PM
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http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html

you think 65cc would be too much
Old 05-03-2014, 03:23 PM
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Ive never experienced 65's to be honest but generally the higher the rating the better the battery is as it discharges more smoothly and more consistently
Old 05-03-2014, 03:28 PM
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It will never be too much C, so this will be fine. The number of the C-rating is how much current the ESC draws when fully loaded, if that makes any sense.
Old 05-04-2014, 12:02 AM
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Originally Posted by Lars from Norway
It will never be too much C, so this will be fine. The number of the C-rating is how much current the ESC draws when fully loaded, if that makes any sense.

This is is effectively the same as what I also said, just another way of saying it I guess.
Old 05-04-2014, 10:31 AM
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so does a higher c rating not necessarily mean the faster the motor will spin? comparing 2 batteries of the same cell count and Mah
Old 05-04-2014, 03:12 PM
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The C-rating has in a way nothing to do with the speed, unless the rating is that low that the battery will not cope with what the ESC is demanding. If so you will be experiencing total cut off, and no speed at all. The amount of cells is what you are looking for to get more speed, 3 will go faster than 2 and so on. The mAh is how long drivingtime you will get.
Old 05-08-2014, 09:54 AM
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Originally Posted by R32GolfTA06
Ive never experienced 65's to be honest but generally the higher the rating the better the battery is as it discharges more smoothly and more consistently
Originally Posted by Lars from Norway
It will never be too much C, so this will be fine. The number of the C-rating is how much current the ESC draws when fully loaded, if that makes any sense.
Both statements are incorrect. C rating is a way of expressing how many amps the battery is capable of supplying. It has nothing to do with how those amps are supplied or the esc. To determine the number of amps a battery is capable of supplying you simply multiply the C rating by the mah rating. So for a 5000mah 30c battery you multiply 5 by 30 and the battery can supply 150amps. Most batteries these days have a single C rating and this is supposed to be the "constant or sustained" rating meaning the 5000mah 30c battery can supply 150amps continuously. Some batteries will have two number in their C ratings and the first will be the sustained rating while the second number is a burst rating usually less than 10seconds. Example 5000mah 30c/50c would be capable of supplying 150amps continuous and 250amps in a burst of less than 10 seconds.

The C Rating has nothing to do with the voltage of the pack either. If you believe C ratings supposedly a single 5000mah 30c cell can supply 150amps. This is bs and one of the biggest lies in rc. If you search YouTube for "C rating test" you can see what happens when you try to push a battery to it's C rating. C ratings are seriously inflated in a game of oneupmanship between manufactures. They can still be used as a guide though, especially comparing models from the same manufacturer just don't take them too literally.

How many watts a motor will draw is determined by the motor, vehicle weight, gearing and the terrain being driven on. All these things determine the load on the motor and how many watts it will draw. You then divide wattage by the voltage of the battery and you get the amp draw unless you have a dark offer that does it for you. The motor doesn't care if your esc and/or battery can't supply the amps it wants, it'll try drawing them regardless. This can result in a fried esc, puffed Lipo or if pushed really, really hard, thermal runaway in the Lipo possibly resulting in a fire.

Last edited by Maj_Overdrive; 05-08-2014 at 10:00 AM.
Old 05-08-2014, 09:58 AM
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great response Overdrive, so will i notice a performance difference in cheeping out and getting lower c rating batteries? Do most esc use all the amps supplied buy high c batteries
Old 05-08-2014, 11:30 AM
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You don't need a 65c battery for the RS4, but the battery could be used in another vehicle that draws more amperage. For the RS4 you'll be just fine with a 30c pack. I run 6s 5000mah 30c in my Castle 1717 powered LST XXL and they're fine.

There can can be a performance advantage to higher C ratings but it has nothing to do with amperage. Higher c rating batteries can supply more amps and can usually do so while maintaining a higher voltage under load. Example, a 5000mah 30c with a 100ampmload on it may be 3.5volts under load, while a 5000mah 50c may be 3.7volts under the same load. This is where higher C ratings can have a performance advantage. Higher C rating doesn't always mean higher voltage under load though, especially if comparing two different manufacturers. Also on vehicles with low amp draw or that aren't pushing the battery hard may not notice any performance gain from higher c ratings. Your RS4 for example may have a 30amp load and a 4000mah 50c might have 3.7v under load while a 4000mah 30c may also be 3.7v under load since it's not being pushed hard.

Last edited by Maj_Overdrive; 05-08-2014 at 01:08 PM.
Old 05-10-2014, 08:57 PM
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The higher the c rating is like a fire hose with the tap turned up or down,its going to give more punch,in our racing meets we all use 60 plus c rates 80 is one of the highest ive used.

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