Yep 8-volt will mess things up. 8-volts is in reality treating the symptoms and not fixing the problem. If the 6-volt charging system cannot keep the 6-volt battery fully charged how can we expect it to keep an 8-volt battery that needs 9.5 volts from the charging system....fully charged.
What needs to happen is you need to fix the 6-volt charging system so it will charge about 7-7.5 volts and that will keep your 6-volt battery up in good shape, your lights will be bright and your truck will start much better...The 8-volt battery will work good when you first install it until the voltage drops below 6 volts or whatever output it can get from the charging system then you will be back where your started. The biggest problems with 6-volt batteries is there is seldom 6-volts in the battery. With 5.0 to 5.5 which is common you cannot expect the starter to turn the engine over and the ignition to provide a bright blue spark on low voltage. It works out far better to get your 6-volt system up in shape....thanks Randy
