Understanding Battery Numbers

[cjegan]

I've done some googling and still have not gotten a good answer to understanding battery compatibility.

I have a 3 cell, 3200 mAh, 20C battery from another kit.

I'm wondering if it can power a FT Sea Duck (recommended 3 cell, 2200 mAh, 25C). It seems the math of (mAH X C) is similar. Obviously the Sea Duck is powering two engines, so probably has more concurrent power draw.

Can someone give me a concise answer of whether the battery would work and (for other newbies), how the smaller capacity but larger C rating affects this setup?

Thanks in advance for the help!

 

[rockyboy]

Your current battery will be a little heavier, but will work fine in a Sea Duck.

They both have the same number of cells which means they will be the same voltage - that's important to not let the smoke out of stuff.

Your current 3200 mAh has more capacity than the 2200 mAh - think of this rating like how big the gas tank is - and your current battery is 50% larger.

The C rating is how quickly you can pull energy out of the battery before it starts heating up to the point it damages the battery - it's a multiple of the batteries mAh rating. Since your current battery is 50% larger that the Sea Duck spec says, it will still be able to handle a much higher draw even though it's 5C less.

Does that help?

 

[cjegan]

That’s a great answer. I guess I was worried about the “c” rating in terms to total amps being drawn.

For educational purposes:
If I had a 3-cell 2000 mAH 40C and a 3-cell 4000 mAh 20C would they be identical except the the second would last twice as long as the first? Or is there some advantage to the 40C that would allow it to put out more power at once (like if it was powering more motors simultaneously).

I feel like I’m set for the sea duck but just trying to learn the math for the future (and hopefully this is a help to other people as well).

 

[rockyboy]

That’s a great answer. I guess I was worried about the “c” rating in terms to total amps being drawn.

For educational purposes:
If I had a 3-cell 2000 mAH 40C and a 3-cell 4000 mAh 20C would they be identical except the the second would last twice as long as the first? Or is there some advantage to the 40C that would allow it to put out more power at once (like if it was powering more motors simultaneously).

I feel like I’m set for the sea duck but just trying to learn the math for the future (and hopefully this is a help to other people as well).

Identical from the perspective of they could handle the same size motor / prop pulling maximum power out of the battery. The 4000 mAh would last twice as long - and also probably be twice as heavy too.

And yes - the higher C rating batteries are good for multiple motors - the quad copter guys especially look for high ratings cause they are running 4 motors pretty hot. Higher C ratings are also good if you're just looking for high performance too.