I was in the process of laying out the dimensions for my front battery box, to cut it out of diamond plate and weld it in TIG class. I noticed, right in front of me, one of the old ammo cans I bought at a swap meet, without logic or purpose. It was the ideal size for the a123 prisimatics, and figured I'd give it a go instead.
I had the choice of bolting the ammo can from the base, which would let me lay the cells flat but looked out-of-place, or bolting it from one side, which looked reasonable but rests the cells on their edge. I bought a couple of these ammo cans to get a quantity discount (did I mention the bit about "without logic or purpose"?
), so for now I drilled from the side and I may try another one the other way later.
Dropped $22 at ACE for a 9/16 metal drill bit, and a bit more for (4) 1/2"x1" hex bolts/plate washers/lock washers. After a suprisingly fast session on the drill press (140mm apart, 20mm and 145mm from the bottom, the ammo can was ready for mounting. I bolted the 32mm clamps onto the boxxer upper stanchions, and the box went right onto them with no fuss. The clamps are large, but happen to land right in gaps in the frame so there is no interference, and they add some agressive look to the forks.
The upper crown does hit the top tube, but I put the bumpers cut from the stanchions no the top tube and they work great. Tight turns are not possible, but the rear end of this bike is easy to pick up and move.
The entire assembly (clamps/bolts/case) weights 5lb 6.4oz without the waterproof lid, and 7 11.5oz with it. This may sound like a lot, but is comperable to or lighter than a rear rack, a sturdy metal case, and hardshell packing on the cells etc. The lid is completely removable, and a whopping 2lb 5oz, I might replace it with something lighter, or I might live with it. This case could just as easily handle the 20ah a123 Prisimatics, just a little less padding.
Power switch and circuit breakers will be inside the case, I plan to open the lid to power on the battery. The lid interferes with the handlebars, so a bad human can't open it enough to pull out the battery. The stem comes off with a single bolt at the adjustable point so I can take the lid off easily enough if I need to.
I like the rough army green, but I will probably give it a few coats of gloss black rustoleum to match the theme. I still need to drill a pair of holes for grommets/8ga power leads, someplace discreet. The top handle rattles so it will come off, thinking about mounting a few cree LED lamps and a DC-DC converter to the the hard points it leaves behind.
This totally balances the bike! I think the size/dimensions are what someone might put on a regular bike to carry stuff around, so it doesn't stand out, adding to the overall stealth. I am tempted to put the black 18 fet methods controller on this, to drive a 5305 to see what 48v200a feels like on a 65lb ebike.
Er, plus the extra weight of said controller/motor.
Now when I get around to terminating the a123 prisimatics they will have a place to go!