Is discharge rating relative to capacity?

[k450]

If I wanted to use a 1200mah/20c battery in a helicopter that comes standard with a 800mah/30c battery, does this mean the 20c rating is good? Likewise a 1600mah/15c would work in place of the 800mah/30c also, right?

[mountaindewdude76]

Originally Posted by k450

If I wanted to use a 1200mah/20c battery in a helicopter that comes standard with a 800mah/30c battery, does this mean the 20c rating is good? Likewise a 1600mah/15c would work in place of the 800mah/30c also, right?

Actually, the "mah" number is your battery capacity. Think of that as the gas tank in your car. I dont have a full comprehension of the "C" rating but I can tell you this....the higher the "C" rating, the better off you are. I use to use 20C packs because they were cheaper. Now, my flying skills are getting better and I'm really pushing my helicopters and demanding more from the electronics, I'm putting more of a load on my batteries. It did not take me long to puff my 20C packs. One of them is puffed very very badly. Since then, I've spent the extra money on some 45C packs and I've been flying just as hard as before, if not harder, and the batteries are showing no signs of puffing and hardly get warm.

Now...if you wanted to use a 1200mah/20C battery in a heli that comes with an 800mah/30, I think you will surely be fine to do that, as long as your CG still comes out right. With a larger capacity battery, you may find that your helicopter is a bit nose heavy. With the larger capacity battery, you would also be able to fly a bit longer. If you are just hovering or sport flying, as long as the CG comes out right, I think you won't notice any difference.

In my experience...a higher C rating is always better.

[RedOctobyr]

Originally Posted by k450

If I wanted to use a 1200mah/20c battery in a helicopter that comes standard with a 800mah/30c battery, does this mean the 20c rating is good? Likewise a 1600mah/15c would work in place of the 800mah/30c also, right?

In terms of the amps they can output, yes, by the specs, an 800mAh/30C can output the same amps as a 1600mAh/15C.

An 800mAh 1C battery could output 0.8A. An 800mAh 10C battery could output 8A. A 1600mAh 5C battery could also output 8A. And so on.

But practically speaking, there's more to it than that. The 800mAh/30C and 1600mAh/15 can output the same amps. But the 1600mAh will be much heavier. Which means the motor will have to work a lot harder to try and get you off the ground. Meaning you also draw more amps, and your motor & ESC run hotter.

Generalizing, it seems like maybe you can to go a battery that's, say, 30-50% larger than stock. I'm kinda making up numbers. But you need to be mindful of your CoG, as mountaindewdude76 said. And you need to consider the overall weight of the heli.

A given heli might fly 4 minutes with 800mAh. Maybe you get 5:30 with 1200mAh (it won't quite scale linearly to 6 minutes, because you're keeping more weight in the air), though it will feel more sluggish in the air, and the motor & ESC will likely be warmer. And with 2400mAh, you might have enough energy to spin the motor at full throttle for 8 minutes, but maybe you never actually get off the ground.

There's a sweet spot to be found, and it will vary based on what kind of flying you're looking to do. Practicing hovering for 5:30 might be perfect for one person, but that setup might be a total disappointment to someone trying to learn tic-tocs.

Going from 800mAh to 1600mAh sounds like probably too big of a jump, to me. Maybe 1200 might be reasonable. If this is a common heli, see what other people are using for battery sizes, that will help figure out what's workable.