I bought 2 Dakota lithium 12 volt 100 amp hour batteries a couple years ago. Love em so far. This spring I had an issue with one of my batteries not taking a charge. Basically I ran the batteries until they shut down. I got back to the camper and charged one battery with no problem. However the second battery wouldn't charge. It was as if the charger didn't even know it was hooked up. I called Dakota lithium customer support and talked to the guy. Described to him what was going on. After a short conversation he asked for my name and address and sent me a new battery at no charge. However the next day I decided to try charging that battery again and this time it charged right up. Haven't had a problem since. Haven't even installed my new battery yet. I was pleasantly surprised by Dakotas customer service.