Hi airbur, the YellowTop you attempted to recharge does not sound like it will hold a charge and should probably be recycled. If the isolated YellowTop was used to power high-demand auxiliary electrical needs, it should be replaced with another YellowTop, as RedTops are not designed or warrrantied for deep-cycle applications. It also doesn't hurt to periodically check voltage levels to ensure proper charging, especially in vehicles with isolated batteries.
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.facebook.com/optimabatteries
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.facebook.com/optimabatteries