Electric power loss

[dboyw]

What is the best, or easiest, way to track down battery power loss? Truck sits for about a week and batteries go from 13+ to 9+ volts.

 

[DaveBen]

Have the batteries (individually) load tested. The voltage tells how high the battery is charged, but the load test tells if the plates are capable of delivering the current to the loads. Replace them in pairs if even one is bad. What yo have is one battery in two places.

Dave