Attention there are calcium/calcium batteries on sale, they can give problems as they need higher voltage for loading. (Like modern cars). It works for a good while but if your car isn't used for longer you get starting problems. For loading you need a special charger too. I got back with the batterie to the man who sold it to me. It took him 2 days on the special charger and he could't get more than 80% charged... Next one will be an lead/lead battery.