C ratings

[Ozzyguy]

My Titan RC 2700mah battery arrived in the post today. Something I overlooked is the discharge rate. To my mind it shouldn't matter. The ESC's will only draw what they are rated to so I shouldn't fry anything. Anyone know otherwise? Also it's a 2 c charge rate so is that 2.7 amp max charge. I forget how it is calculated

 

[ElGuano]

My Titan RC 2700mah battery arrived in the post today. Something I overlooked is the discharge rate. To my mind it shouldn't matter. The ESC's will only draw what they are rated to so I shouldn't fry anything. Anyone know otherwise? Also it's a 2 c charge rate so is that 2.7 amp max charge. I forget how it is calculated

You didn't post the discharge C-rating of the battery?

If it's 20C or above, you'll be fine. The Phantom works with the stock batteries at 20C, and a 2700 at 20C can discharge faster than a 2200 at the same rating.

1C is 2.7A for that battery, so 2C is a 5.4A charge rate.

 

[Ozzyguy]

Yeah that's what I thought for the charging but I second guessed myself. Ooops on the discharge rate. It's 35-70 C

 

[ElGuano]

Yeah that's what I thought for the charging but I second guessed myself. Ooops on the discharge rate. It's 35-70 C

35C is more than enough. It's getting to the point where I'd wonder if the higher weight of the big-C rating is starting to eat away at the flight time, but that's just me; it's generally not a problem.

 

[Ozzyguy]

It's actually lighter than my turnigy 2200

 

[RichardWendt]

IMO, charge at 1C was the safest way for your LiPo batteries pack

 

[Big Ben]

If you could and would use 100% of the charge then in theory a 20C battery could be discharged at that nominal rate in 1/20th of an hour or 3 minutes. You'll have to have a pretty heavy bird and do some very aggressive flying to run it down in that short a time. At 6 minutes flying time the drain is reduced to 10C and because you'll use perhaps 80% of the charge in that time the real drain will be lower again so a battery with a true 20C rating should be up to the task of powering a Phantom perfectly well. A higher C-rating isn't really necessary.

 

[Ozzyguy]

I wasn't really concerned with the C rating when buying. More so the extra capacity. As long as it was over 20C

 

[ElGuano]

If you're doing really acrobatic flying, or given to punch the throttle a lot past 50-60% of the battery, you can get some benefit to a higher-C battery with less voltage sag. But it's nearly impossible to find a flight battery sold that is too low for the Phantom. It's like trying to buy a 3mp DSLR today. Everyone just looks for the highest rating without considering if they need it. One of the batteries I ordered is 8C (but much larger in capacity), it's made for AP/AV flight.