There are stories around that using a tender while the battery is still hooked up in the car can create an electrolysis situation with the aluminum engine and it's proximity to other metals. I can't remember which DeLorean vendor told me this but I was told they'd seen engine blocks eaten away inside. Whether it was from a battery tender, extremly old antifreeze or a combination of the two I can't say but I think I'd prefer to disconnect the battery prior to hooking up the tender to be on the safe side. Bruce Benson > If you are really concerned about the battery, I have used a Battery Tender to charge a > dead battery and keep it stored for months: > > http://batterytender.com/product_info.php?products_id=2 > > You don't even need access to the battery. Open the louvers, pop the engine cover, clip > red onto the positive post (right side, in the wall, big red cable) and the black onto a > clean metal part of the engine.