### Questions about 3DR battery

Hi guys,

This is the document for 3DR Iris battery: http://3drobotics.com/wp-content/uploads/2014/01/extra-battery-document-v2.pdf

The ratings for the battery are 3s / 11.1V / 3500 mAh / 30C (105A)

1. I'm not sure I understand this standard discharge rating. 30C means the battery will discharge fully in 1 hour / 30 = 2 minutes? So the battery will be drained in 2 minutes? Except it doesn't...

2. The Iris is advertised as having 10 minutes flight time. So if I wanted to increase this flight time to say 20 minutes I would have to double the discharge from 105A to 210A? Is that correct? So I would have to put another 3s cells in parallel with the original 3s to make a 3S2P pack?

Thanks a lot

#### Replies

• Take all of the specs you have for the Iris and plug it all in to ecalc (http://www.ecalc.ch/xcoptercalc.htm?ecalc&lang=en)...this will let you tweak battery size as well as other parameters to see what will give you the best flight time.
• and no, the discharge rate is more than good enough, in fact, if you purchase 7Ah 15C battery , it will still be enough, because 7Ahx15C   ==    3.5Ah*30C

• 30C is the maximum continous discharge rate - it says that the battery will handle up to 30x3,5A current.  It does not say that you will use that much.

If you can fly 10 minutes at a certain capacity*cellcount , doubling the batteries, will not fully double the flight-time - because you also need to carry more.

This reply was deleted.

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