I use a 140L on the back and a 140 Daytime Running Light (same as the 140L but with an Amber lense) on the front. I've got them connected together through a Y-Adaper to a 4-cell external battery pack. The external packs are small and light enough that you can find many places to stash them on your bike. The packs are waterproof and will power a 140L for something like 24 hours in certain flash modes. Plus the same pack will work for a Dinotte headlight if you ever get one of those.