I know this has been discussed before, but I just got a battery watering system from Powerstride battery in San Diego. $128.00 for a 16 cap system and $35.00 for a 2.5 gallon tank. Simple to install. They set up the caps to the batteries you have to regulate how full they get. Has a quick disconnect fitting to hook tank to tubing on the batteries. For 2 banks you only have to get the 16 caps and tubing, can use the same tank. PM me if you would like any more info. John