Lead works fine if you can deal with the related problems from it. Most people don't use their ebike the way you are whereas, you are running the pack and sitting for hours at a time. The point that Sangesf is promoting is more or less on track. To control sulfation in a lead battery is to have constant current flow. But if your going to invest in more lead you may as well bite the bullet and go lipo or lifepo4. However, to my knowledge current in is as good as current out to control sulfation. So look for s small solar charger at places like Harbor Freight or Northern tool. You maybe about to find a low cost setup that will give enough currect to not only stop sulfation but give you a little kick back for your return trip. If you find a unit at Harbor Freight you can find 20% off cupons in many magazines and news papers. So if you founs something for say $40 less 20% ($8) you might solve your problem for 32 bucks. If you sign up for their cupon new letter online they sometimes have a special on solar chargers. Bob


EDIT:I just looked a solar pannels and chargers at Harbor Freight and you won't find one for 40 bucks. But it still might work for you.

BTW, what is the voltage and AH of your pack?