Batteryspace discount alert! Don't order from them yet! Before I prattle on about building the pack, check this out: When you order, one of the pages that you go thru has a fill-in for "coupon code" or "discount code" or some such. Just type in "batteryspace", and poof!, it knocks 5% off the pre-shipping total. Sorry I didn't post this earlier, for anybody who's already ordered. Hey, maybe they'll let you take it off after the fact...
Now, back to our regularly scheduled prattle...
It's done! I bought two 4xAA covered holders, plus one 2xAA, at Radio Shack. 'Course, the problem was, the 2xAA is, like most, a series holder, so I still didn't have 5+5. So I hacked it. I removed the "crossover" terminal bar (the one that connects the positive post of one battery to the negative on the other), and broke it in two. I made sure to break off a bit of the metal in the middle, so the two would never touch. Then I drilled some new holes in the housing, soldered wires on the two pieces of terminal that I had just busted, and put them back in place. So now that 2x is really two singles.
Why? 'Cuz RS doesn't carry a covered single AA holder. Nobody makes a 5x. I saw some 3x'ers on the 'net, which I could have put in series with a 2x, but they weren't covered, and shipping for such a wimpy little order woulda been a killer.
So I put the two 4x'ers back to back, and the 2x on one end of that assembly, using double-face tape and duct tape. Series wired each 4x'er to the two singles that I created, then parallel connected the two strings to the wire that I resurrected from the shot SLB pack. I was hoping to do the extreme hopeless geek tweak and heat shrink all the wiring, but alas, I couldn't find the stuff. So I just soldered and e-taped all the connections. Total part cost: about $5. Assembly time: coupla hours, given I was watching TV at the same time.
The enclosed holders are nice. Yeah, the whole thing sits in a little nylon pouch that hangs on the frame, but the enclosed holders offer more weather protection. And I don't have to worry about cells popping out on bumps, etc.
The whole thing takes up about as much space, and weighs a whole lot less, than the 2.5AH SLB pack. And with the parallel connection, and the 2AH batteries on order from batteryspace, this pack has a 4AH capacity. Should give me 4 hrs run time on this bulb. If I choose to put in a 10W bulb, I'll probably get 2-2.5 hrs run time. Sweet!
Here's a weird thing. The 4x holders have switches. When I switch either one off (or pull a battery out of either string), I'm effectively running on just one string. But the voltage should remain the same, right? Well, the light dims just ever so slightly. Thinking that it's one string having slightly higher voltage than the other, I switched it back on, and switched off the other string. Same effect. I checked the voltage with either string on and both strings on. It's always 6.45V. So for some reason, having more charge allows the bulb to draw more, and burn brighter.
I'd post pics, but my digital camera is shot (dropped it on a tile men's room floor last weekend; don't ask).