Yeah, we all know that problem. I just thought the cost of the SLAs + the trailer would be about as much as the lipo4 pack. Keep in mind the life capasity of the SLA vs. the lipo4 isn't even close. I started with the SLA packs and now realize I made a boo boo. Of course it all depends on how much you pay for ether and how you use them. I am very kind to all my packs and they have held up well for me including the SLAs. By teh way my 2 - 24v 18ah packs that I was carrying on that bike is the same as your talking about carrying and they worked fine on the crotch bar. But now i wish I had a small trailed to carry my dog with me.