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 lipo C rating

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crash1983



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Age: 30
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PostSubject: lipo C rating   Sat May 14, 2011 7:58 am

what does the C rating mean and what is the lowest rating that should be used in a rustler with Castle SCT system
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THEANVIL



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Age: 18
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PostSubject: Re: lipo C rating   Sat May 14, 2011 8:22 am

C rating means bassically means the amount burst of power and the continus of power when your flooring it down the straight, and when you take off. But when you look at a battery it will probably have 2 C Rating "Burst" "Continus". So the higher the C rating the more burst of power and the continus of power when your on the gas. For you Mamba Max SCT system I wouldnt go lower than 25-30C. Remeber the C rating can be part of how faster or slower you go topspeed and the how fast the distance you cover with the lower or higher C.
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Dominator
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PostSubject: Re: lipo C rating   Sat May 14, 2011 12:37 pm

I'll start by saying an electrical engineer type such as Romano will probably laugh at how I'm going to explain this, but I'm going to give it to you in simple layman's terms that are practical for how you use your RC cars.

"C" is a letter value given to equal the battery's capacity rated in amps meaning that 1C is equal to the capacity. "C rating" is the total amount of amperage the battery can put out based on it's capacity.

To calculate or understand a "C rating" you first need to convert the battery capacity from milliamps (mah) to amps which is really simple, you just at a decimal point. So it goes like this... a 5000mah battery is 5 amps, a 4600mah battery is 4.6 amps, a 4200mah battery is 4.2A... and so on. The amp number you just got is a "C"... so for a 5000mah battery, 1C = 5A.

Now the "C rating" is the "C-number" multiplied by the amperage. So using our 5000mah example again... if it has a 25C rating with a 40C burst, it means that the battery can safely put out 125A (25 x 5A = 125A) of power continuous (25C) and 200A burst (40C) - burst meaning a quick 5 to 10second surge of power like accelerating from a dead stop.

This goes for charging also. What they mean by saying you can charge your battery at 2C means you can charge at twice the capacity. So for a 5000mah battery, you can safely charge at 10A.

The problem is that marketing has caused people to put way to much emphasis on "C" ratings. People are paying big money for batteries with a 60C or 65C rating. Do you realize how much power and heat that puts out?!?!? If a 5000mah battery can put out 65C, that would be 325A which would more than likely melt the ESC, wires, solder, and/or connectors. Even the hard core drag racers aren't pulling more than 200 or so amps, so that means the average racer and basher are NEVER going to pull that many amps.

When buying lipos, make sure you stick with a quality brand. I don't mean high dollar, just a name that you know people use successfully with no problems. Stick to about the 5000mah range, give or take a couple hundred mah's and a 25C to 30C rating is more than adequate. Save your money and avoid the hype of the 45, 50, 60 C batteries. If you want to buy batteries locally, the Dynamite brand batteries are a good value. They are good quality and fair priced. If you want to order online and wait for a while, you can try some of the Turnegy and Zippy batteries from Hobby King. Many people use them with no problems, however while I worked at Randy's I saw several failures where the solder connections come loose, or the cells puff up and in a couple cases a brand new battery was below voltage and completely dead. There are many other brands out there, just ask around... but remember you don't need a super high C rating, it's just a waste of money. However, I would not recommend Venom batteries. I really don't trust them. I've personally seen some bad things happen with them.

LiPo ratings can certainly be more in depth with a lot more information out there, but that's the basics of it in a nutshell. I hope that helps and I'm sorry to be so long winded but "C" ratings confuse a lot of people so I just wanted to try and give a good explanation.

-Dean
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crash1983



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Age: 30
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PostSubject: thanks Dean and Wes   Sat May 14, 2011 3:14 pm

thank you for the info. I will stick with what yall are recommended
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Germanese
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PostSubject: Re: lipo C rating   Sat May 14, 2011 3:46 pm

Shocked Notepad ... !!!

I should make this a sticky
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THEANVIL



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PostSubject: Re: lipo C rating   Sat May 14, 2011 8:37 pm

Yea Dean I was going to say that too. about Romano.
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snellemin



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PostSubject: Re: lipo C rating   Mon May 16, 2011 10:23 am

You did good Dean.

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Guff



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Join date: 2011-05-06

PostSubject: Re: lipo C rating   Tue May 17, 2011 8:33 am

How does the size of the motor, or scale come into play from an amp draw perspective?

For instance...what kind of amp draw would a 1/10th scale running a 2S pull as compared to a heavier 1/8th running 4S?
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snellemin



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PostSubject: Re: lipo C rating   Tue May 17, 2011 9:33 am

Well, you are comparing a 2s vs 4s in two different vehicles. Too many variables to deal with. The 1/8 and 1/10 can equally use the same amperage no matter the chosen voltage.

Motor design dictates power and not the physical size of the motor
A Lehner Basic XL motor is the same physical size as a 1/10 540 motor. However, the 2 pole little Lehner puts out the same power as a 4 pole 1512 Neu motor.

So to make any sense here, you have to look at it differently.
A family of motors all produce the same amount of power. For example the 1512 Neu motors all produce 1000W of continuous power. The Turn of the motor dictates the Voltage and amperage needed to come up with the 1000W. So you choose your batteries C rating based on your powerplant/motor.
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Guff



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Join date: 2011-05-06

PostSubject: Re: lipo C rating   Tue May 17, 2011 9:54 am

Too technical there bro.


I have 1 - 20c 5000 mah that I run in my short course. I was hesitant when I bought it, but it was so cheap I gave it a shot. It's fast..runs with no problem and is just as fast as every other SC. I don't believe a 20c would do well in 1/8th scale though.
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snellemin



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PostSubject: Re: lipo C rating   Tue May 17, 2011 10:22 am

A 6S 20C will do well with a low kv motor. Would be a more cheaper an more efficient setup. But for 1/8 scale with off the shelf motors, a 30C continuous is recommend on a 4s setup.
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