Hey guys! In the ongoing quest for efficiency in flight times and redundancy I have been rethinking my battery setup. It came about from a guy over on RCG (Redemtioner) and he does some very cool builds and swears by a lipo per motor. Specs on my multi: X8 with U5 (tmotor 15x5 props) and AUW of ~24lbs I currently fly dual 6S 6000mAh packs @ ~890g each (total 1780g) which gives me 11-12 mins of flight time. My thinking is if I change to quad 4S 3300mAh @ ~350g each (total 1400g) should give me more mAh and lighter which equals more flight time? Or is voltage a factor that I am not thinking of... I'm pretty weak in the electrical science stuff.
Voltage is a big factor. Motors are measured in KV, which translates to revolutions per volt. If you drop the voltage your motors will spin more slowly at equivalent throttle percentages. More flight time can be achieved by adding more capacity, or mah to your battery setup. It takes more power to carry more battery weight, so adding more can be a bit tricky. You'll start running into diminishing returns, and decreased overhead. Knowing what throttle percentage you're running at currently can help to determine how much room you have to add more capacity without needing to modify the motor/prop combo.
Ah well there you go, I knew I was missing an important factor. Possibly smaller 6S lipos on each arm is the answer. Weight may not go down but safety would be good.
Here is the direct post of his builds... you can follow the discussion where he explains it. http://www.rcgroups.com/forums/showpost.php?p=26730321&postcount=1238
Good luck with all those connectors. Google "Single point of failure". You do know that having 8 batteries vs. 1 or 2 batteries introduces a dramatically higher probability of a battery failure (or even a partial failure) taking down your copter? When it comes to redundancy, you have to figure out what's going to fail, then back that up. Otherwise, you're making your copter more likely to fail, not less.
This is pretty much why I only really hang out here now. I really appreciate the experience and knowledge that's available to tap into. I see what you mean Steve and it makes sense... My setup now is working great now so I guess "If it 'aint broke, don't fix it!". My Turnigy nano-tech bricks are not the lightest, I know many of you use QC packs... Are those the best way to go?
I'm using Pulse and Tattu 10000 6S packs in matched pairs. AFAIK, they may be the same packs with different labels.