[awfink55]

Archrms, Your battery problem is unusual and a concern. I use a battery tender on my Cobra and 2 other cars without a problem. So, you may want to disconnect both battery cables from the battery and then put the tender on the battery. This isolates the battery from the car. If the battery keeps the charge and does not overcharge and heat up, then, your problem is related to the car to battery relationship and further investigation is necessary. Hope this is helpful.