I would be interested to share what others are using and how they have their power systems set up and what they find does and doesn't work. .
I am using a 3300mAh 4S 35-75C Turnigy battery and I'm in the dark about what to expect from this considering it might even be to small for my X8 Quad (880kv motors 30amp ESC)I have done a number of 2 min flights and haven't really pushed them past this. But what happens if it is under powered during flight?
I ready just recently that for the health of the battery it should not be allowed to run below 80%.
See this interesting page on batteries http://www.rchelicopterfun.com/rc-lipo-batteries.html
I'm a bit confused on this. Does it mean its ok to draw 80% out of the battery and not below this or does it mean draw 20% out of the battery and leave 80%.
What voltage levels are others letting the battery drop before it is regarded as time to land?
Thanks Russell. this is very helpful. So do you know, is the percentage shown on MP for volts sown or mAh's? Also any Idea why I have nearly 1volt difference from what Mission Planer is showing compared to my multimeter?
The percentage is mAh's. As far as the voltage difference, assuming you have the correct number of resistors solders, you may need to recalibrate the voltage sensor.
Run through the setup for calculating the battery voltage: http://code.google.com/p/ardupilot-mega/wiki/Voltage
Just read through your conversation here, you may need to fudge your voltage division to get the correct voltage reading.
I have two 3300mAh 4S batteries which I have been only using one at a time.
I now want to use the both together in parallel which I assume is ok right?
I have made up a cable to connect the two batteries to and a single plug at the output end for the copter. Before I go connecting them up in parallel and risk blowing them up in a fireball, is there anything I should be aware of in doing this?
Also is it possible to charge them both together like this?
Running the batteries in parallel is fine. Make absolutely sure your wiring is correct and that you won't be shorting the batteries when you connect them in parallel.
You can charge the batteries in parallel but you won't be able to balance charge them in parallel.
Thanks for confirmation Russell. Yes I always double check connections with a multimeter and especially for DC power. Ive blow up plenty of things in my time :)
Why would the AttoPilot battery sensor I'm using get so hot it melts the solder? I checked I have the in and out connected in correct order. Is it normal to get so hot? I have used it in two other flights and noticed it had slightly melted the tape I put around it, but today it got so hot the solder melted and the resistors slid off off the board and I lost power. Any Ideas on this?