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

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?

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  • This is a greatpage, he gives me a lot of information.

    Global electronic components distributor -Allicdata electronics
    Allicdata offers electronic components, semiconductors, antennas, capacitors, connectors, diodes, transistors, IC,resistors, huge quantities products…
  • Parallel connection of power sources, in electrical industrial plants, is strictly forbidden. A separation devices is mandatory to avoid reverse current flow and to protect the load against a single power failure. Use of silicon or shottky diodes is not suggested because of the too high voltage dropout. We developed an ideal diode device to safely connect two or more batteries without any power loss

    Russell - said:

    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.

  • 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?

  • 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?

  • Could others please advise what battery reading use off the Mission Planner to gauge when to stop flying. What voltage level and percentage is it at when it is time to RTL?

  • I did some testing on my rack today and seems some differences from the voltage reading on Mission Planner compared the the multimeter reading. Start of the test Multimeter reading was 16.75v. MP was 15.95

    After 3 min running then the multimeter reading was 15.68v and MP was 14.89v

    I did as advised on the battery sensor instructions to subtract 0.3v from the power supply which on mine is a 5v/3amp switching regulator. I set this to 4.7v.

    I assume this is to compensate the difference in the draw off power from the APM?  Any idea why there is nearly 1 volt difference from the multimeter and the MP reading?

  • I use one of these:

    As the battery gets down, it gives a beep or two (loudly), then more rapidly and when the battery is done, it beeps like crazy.  It also has an LED that gives an idea of battery status.

    They mean you can use 80% of capacity, leaving 20% in the battery.

    Is 3300mAh light on?  Could be.  Depends on the load you'll be carrying.  This calculator can give you an idea of run time:

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