My Wife and I have two identical FreeGo folding e-bikes. About three years old, bought brand new. We use them a lot. Always out together. One failed completely when 15 miles from home. I rode home for the car. We took it to the bike shop and they fitted a new controller as it was burnt out.. Fine. The other has started going less and less distance on charge and now will only do about 17 miles from full charge..This is on power setting two. We have swoped the batteries with no success. I took the cover off the lower controller box and found several burnt, melted and fused wires, which I taped. Still the same . Do we need a new control box and are they easy to fit please.. I also noticed water had been getting into the compartment which is not surprising as there is no gasket or seal. Any advice would be greatley appreciated. Thank you.