Bought a pair of Interstate "ECL Pro" 27's right after I bought the van last August. They seemed to be fine but then dropped off rather suddenly last month. Last real camping use was Thanksgiving.
Went back to the Interstate store a couple of weeks ago and they said the batteries 'seemed okay' but didn't load test them. The just offered me two new SRM27 batteries under warranty. Each one has about 10ah less than the "Pro" version. They said they had a very high return rate on the Pro series batteries and had much better luck with the SRM's.
Tested the SRMs for the first time yesterday by turning on the fridge. They went from 12.8v down to 12.3v in one hour. Took them back to the store today and they load tested one of them. It was at 12.87v but had
0 cranking amps. The tech guy looked confused. This is our local Interstate distributor/warehouse; not an Interstate dealer. They didn't bother testing the other one and just gave me two new SRM 27s. I had to get back to work so we didn't have time to load test the new ones.
Installed them tonight. Leaving tomorrow to go camping for three days, so we'll see what happens
So far, Interstate has left me with a bad taste in my mouth. Maybe a couple of reliable batteries, a marinated pork loin, and a New York Strip will fix that.