There is another advantage to using the dual diode method for multiple batteries. You can mix chemistries without concern. for example I have 2 LiFePo4 packs and 2 gel cells. I can use a gel and a LiFePo4 on the same flight. Power is simply drawn from the pack with the highest voltage, until both are depleted. You can't do this if you wire the batteries together directly. You can, if you use two switches of course, but you run the risk of voltage spikes or drop outs on switch over. You also don't have to monitor voltage for when to switch from one to the other as no switching is needed.

I also second automotive blade fuses at the battery terminals. Additionally I use screw-type battery connectors (3 conductor type) as they are robust and lock in place with the threaded ring.

Matt H
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