The basic calculation is very simple.

A 1000mAh battery will deliver a current of 1000mA (1000mA = 1 Amp) for 1 hour

So mA X time in hours = mAh capacity.

Couple of things to remember though:-

1. You cannot assume to use the full capacity from your battery

2. Your receiver may draw only 16mA, but most of the load on the flight battery is applied by the servos. Just what this is depends on how many servos you have, what type they are, and how much you use them in flight.

3. The good news is that your Tx load should be pretty much constant, as the Tx is always transmitting when it is turned on and most of the power goes to the rf stage. Your Tx will have a meter anyway so you should be able to keep an eye on it. Surprised you cannot find larger Tx batteries, I use an 1100mAh in my JR.

For flying with 4 or 5 standard servos I normally use 800mAh batteries and find them sufficient. I normally take two planes out with me and find that I can get as much flying as I want (it is not my usual habit to spend a day flying in gentle circles either[>:][>:][>:]

Hope this helps


Terry