It's normally at four in the morning when sleep evades me that I draft these designs in my head, and consistent with this I fix upon the ideal arrangement. I'm unable to use the previous location (a bay within the top of the phone-box) because you'll recall to avoid purchasing plastic tubing in bulk we were limited to lengths of one metre each. This in turn means that there is no head-space within the box available to store the batteries as we wished.
Nonetheless this configuration has, if anything, more to recommend it:
(a) 6s packs of around this size come in a range of capacities and sizes
(b) the weight is entirely centred and arrangement wholly symmetrical
(c) it eliminates the need for a battery-bus or power distribution board
(d) replacement costs are lower in the event of a single-cell failure
(e) it uses little extra space because it surrounds the Pixhawk cube
(f) everything remains top-mounted on the drone for easy access
(g) which also means that the drone and box are closely coupled
(h) the battery leads can be specified to required lengths to suit
Fortunately in Lancashire we've a supplier who assembles packs from individual cells, allowing lengths of leads to be matched to suit the implementation. We are unable though to proceed as yet until the airframe has been re-built and the motors and ESCs fitted, so that we can determine exactly what length of lead we are talking about.
The worst time to be doing all this of course is in the run-up to Christmas, during an Arctic freeze and any number of postal strikes... but it was Richard Branson who said the best time to start in business was during a recession, because nobody else would be stupid enough.
What we can do whilst we wait however is to recalculate the sort of packs we might need in view of size, weight and flight-endurance constraints. I've always been bigger on the practical build than the calculations and wholly moreso than the accounts, but needs must if all of this is to succeed.
