My 2015 Somerset E3 has a Interstate Battery SRM-27, which was installed by the dealer in early October of 2014. When we camped in my BIL's backyard just after Christmas, the roof lift wouldn't work from the battery alone - sound of the motor turning until it came under the load of the roof and then it stopped due to the current limiter in the controller. After plugging into shore power (15 A circuit using an adapter) the roof lifted up fine. It also came down just fine. The temperature that day was in the high 30s or low 40s. I have not had a chance to try it out since. Being that I live in Southeast Texas, I'm used to batteries only lasting around 3 years or so in vehicles. The camper is stored in a garage and I do regularly check the water level, adding distilled water as needed. We camp with shore power everywhere we go, so the battery typically doesn't get much heavy use or deep discharges. When we're not camping I plug the camper into the household power and the camper has a good multistage charger/maintainer builtin to the converter/fuse box. I'm not certain that the battery is going bad yet or that I don't have some other issue going on. The camper manual does state that the roof should be able to be lifted by the battery alone, at least once up and down. It also states that the converter alone isn't enough power to supply the roof motor and a minimum of a group 27 is needed to supply lift the roof. I can go into detail as to why the design is as such, but for now I'll leave it out. (Being an Electrical Engineer I went through the design in as much detail as I could after purchasing the camper out of curiosity.) My question to the knowledgeable multitudes gathered here is what is a good way for me to go about testing the battery? Would just taking the battery to an auto parts store and have them test it with a battery tester be enough? I'm not certain if the battery tester at auto parts stores is more testing for voltage drops at cranking amps levels vs the voltage drops at lower, more sustained currents.