I had a Harbor Freight cheap Battery Tender years ago connected to my 1975 Corvette. I had a good Interstate sealed side post battery. Corvettes have the battery inside a fiberglass box behind the drivers seat with a latched sealed lid. I don't drive the Corvette that much. about 15 years ago, I decided to start it up after sitting for about 3 months. Battery tender still connected. The minute I turn the Ignition key to start, BAM, the lid of the battery blew off and luckily the battery compartment lid kept the remnants IN the battery box. The Battery tender had boiled the battery dry and the Instant draw from the starter combined with the Battery minder connected provided the spark to blow the gas. Lesson learned. I purchased a more expensive Battery Minder and now I monitor the Water Level in the battery before I run the car now. NEVER had a problem in the past 15 years using a GOOD Battery Minder. Doug
