Personally, I'd buy a new charger, even though you are probably near the end of your battery's life. And I'd buy one that let me select the battery technology for each bank. The reason I'd buy the charger now is it'll work with your current battery and if you upgrade your starting battery to lithium, you already have the charger. I have a three bank, ten amp NOCO and have had no issues i the two years I've had it. Six of one and a half dozen of the other I suppose.