It didn't take long to charge, and since the warranty period has expired, Optima won't do anything for me. As a result, I ended up in the trash, which is a waste of $200. I have had no problems with Optima products over the years as almost all my cars have red tops but it was a waste of my money. Update, still no help from Optima. Very disappointed. I will buy a new charger, definitely not this one. Spend your money elsewhere, all the negative reviews have a reason for this device, it doesn't last long and you don't get any support from Optima.