Don,
Thanks for the info. Next spring, I may opt to get a second rack mount battery case with fresh SLAs and then might swap out the SLAs in my current case with Ping batteries. The bump out you did to the case, did you actually have to cut the case? Were Ping's two units too long for the Currie case? If it's not too much trouble, when you have a chance, could you post a picture of your modified case? I'd like to be keep the center of gravity low by using Currie cases on the rack, but with LIFEPO4.
I have no problems getting 25 miles with my SLAs (I pedal all the time), but I know their efficiency will decline by next summer. I really am having fun exploring the forest roads here and would like to be able to go up some of the forest roads on the higher mountains next spring and summer, which will mean having two battery packs--one fresh SLA and one LIFEPO4 would be a nice combo.