Recently I had a quadcopter crash when the single LiPo battery exploded. I am exploring ways to prevent a similar crash. One idea is using two batteries in Parallel protected from each other physically.
Electrically what happens to the second battery if the first exploded? Does the second battery short out? How can one be protected from the other?
thanks, Bruce
You mean that during the flight the battery exploded and so you crash ?
Yes the battery exploded while the quadcopter was 200m at sea and it crashed. The quadcopter was retrieved.
I’m trying to work out how to prevent this, possibly with a back up battery.
It is a rare event, never heard about a battery exploded during flight.
Having another battery connected in parallel is not a solution since if a single cell of one of the two batteries fails then the battery with all cells ok will “charge” with all the Amperes available (a lot) the defective battery wasting energy and completely destroying the other cells of the battery where one cell defect.
A true backup battery would have half the capacity of the main battery , enough to abort mission and return home, and a SSR relay system that when the main battery reach a low voltage limit will switch from one battery to another .
The drawback is that you will always carry a ballast .
The best solution is to use a high quality battery and a system to monitor the status of the battery, single cells voltage and battery temperature to detect when the battery start to fails.
Thanks for your replies guys.
Hard to ensure batteries are high quality, very limited selection available in New Zealand and how is quality verified.
Checked out LiPo decoupler but unfortunately insufficient amps capacity for my purpose.
Bruce,
I agree with Luca that battery failures are rare, but in case it happens it can be costly of course, depending on the size of your copter and cost of equipment attached.
I started building a lipo Or-Ing device a while ago to prevent issues with one battery affecting the other, but it got deprioritized… just too much things to do, too little time 
Have you read that the lipodecoupler can be “parallelized”, maybe you can reach your current needs by using 2 or more in parallel per LIPO battery?
Maybe something like this?
Could I ask the reason of battery explosion?
I have seen it before, but that time battery was physically impacted from detaching on the frame.
never heard explosion in the air.
Battery exploded under load, in flight , no subsequent investigation of why.
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