It turns out the bigger battery pack was just what the doctor ordered: a slope that used to reduce the 3WDM to an embarrassing crawl is now hardly noticeable. Not that I'm about to take the thing up Alabama Hill, but the trip back from work should now be possible without the thing pooping out half way up F Street.
The first draft of the battery mounting consists of eight footman fittings with some webbing and associated buckles. I'm not particularly happy with it, since the batteries still move around much more than I'd like. Part of the problem may be the cam-style clasps I'm using, which depend on introducing a bit of slack into the webbing to stay closed. That, in turn, allows the pack to slide around along the length of the board, which just now disconnected one of the front weight sensors.
I also need to make the pack wiring a bit more reliable. The two major issues are semi-adequate insulation, and the fact that the wires I'm using are quite stiff. The problem with the latter is that vibrations will eventually cause something to fail if the wiring can't flex easily. This weekend I'll try and pick up some nice, floppy 10 AWG wire and a 10k Thermistor at the nearest electronics store (a tossup between Vancouver and Mount Vernon). I'm also thinking of re-doing the wiring on the ends of each stick in the pack by snipping open the heat shrink tubing, soldering on the wires, and putting on a new piece.
Then I just need a better method of strapping the cells to the deck and I should have a good, solid pack.