Electronics, Lighting, & Gadgets - What would be the best battery for me?

I have previously used a 5.0 AH SLA battery mounted in my rack trunk for my DIY lights. Even with velcro strips, it bounced around back there and sometimes the connecting wires came loose.

For my new system, what would work better? Here are my requirements.

A) Run high beams (20W + 20W MR16s) for about 40 minutes, plus, run single 20W beam for about 2.5 hours.
B) needs to be waterproof

I'm thinking about something mounted in a water bottle cage. What do you suggest that will give me the run time I need?

Something like this is close. My math said you needed 5.3 AH at 14.4V. But you said you got by on 5 AH before.
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3261

Right now I am using it less than what I posted up top, but will be needing a longer run time in the near future.

I have previously used a 5.0 AH SLA battery mounted in my rack trunk for my DIY lights. Even with velcro strips, it bounced around back there and sometimes the connecting wires came loose.

For my new system, what would work better? Here are my requirements.

A) Run high beams (20W + 20W MR16s) for about 40 minutes, plus, run single 20W beam for about 2.5 hours.
B) needs to be waterproof

I'm thinking about something mounted in a water bottle cage. What do you suggest that will give me the run time I need?

If you can, I'd split the second light and run it on it's own battery. A 3.3 Ah battery will run a 20W bulb at 14.4V for about 2.5 hours. That way you can burn all your lights all the time. It's more batteries but it's also more light. Go to a 4.2 Ah RC car battery and you'll have lots of cushion. Look (http://www.bikeforums.net/showthread.php?t=368772) at how I carry mine

Run time is going up soon to that which I posted on top.

***Run time is going up soon to that which I posted on top***

It looks like you're a little over what a single nimh bottlecage pack might provide, then. You could use 2 packs, or... You could switch to led's to cut the power drain. Just a thought. I love my sloppy, home-made led lights, and I run them on el cheapo Energizer AA's. More light, less power, longer life, tougher. What's not to like?

OK, let me clarify. I'm delivering newspapers. While I'm on the route I'm not going fast enough to need really bright lights. So for that all I need are "be seen" lights.