I have a 2005 F250 diesel. It is driven to pull a 5th wheel during the summer season. During the winter months it has been parked for extended tome periods. It seems this does not keep the batteries adequately charged. The vehicle wouldn’t start recently due to discharged batteries. Ford dealer placed charge on batteries but said they won’t hold it. Should I be periodically placing a charger on the batteries (either these or new ones when there replaced)from now on? The vehicle is kept in a garage and temp is always above freezing.
You need 2 battery minders; they are really trickle chargers, and keep the batteries charged up as needed. It’s not a good idea to let the batteries run down conpletely, even if the temperature is above freezing.
The batteries should be connected in parallel, one charger should do it…Disconnecting the batteries will greatly slow down the rate of discharge…
When batteries are allowed to discharge slowly and not kept charged, they will sulfate, which usually ruins them… Sometimes a prolonged trickle charge will restore them somewhat, but they will never be the same…
Clarification - are you saying the batteries are already connected in parallel or that it is something additional I should do?
The FACTORY connects them in parallel to supply the cold=cranking amps required to start a cold diesel…If you connect a charger to one, they both will (should) charge…
You should be aware, if one battery fails, it will drag down the other battery…So for testing purposes, they should be disconnected from each other and charged and tested separately to be sure they both have equal voltage and power…By disconnecting ONE negative cable from one battery you will isolate them from each other…
If a load test reveals one battery has 10.6 volts and the other has 12.6 volts, replace them both…