Why do the dual battery mod?

[Randy]

Unless it came from the factory, dealer installed or added by a previous owner they don't come with the wiring. If it did there would also have the battery tray installed and the isolator, ground cable. Parts could have been remove..

If you need a kit Painless, Wrangler and others have them..

 

[happy 3345]

has the wiring hanging on the pass side there the connector probably going to have gm to hook it up.there very limited info on how to complete the wiring.and no i dont wont to use anything that not factory just my idea doing something that doesnt look factory i dont

 

[Randy]

Sounds like you think it came with that option. Go the dealer and get a parts list of what you need/missing and buy them or track the down online or junk yard.

 

[happy 3345]

going to gm dealer and let them hook up the relay trigger wiring on the fuse box as stated the plug is already hanging there

 

[Randy]

Soo it has the battery tray, isolator..

 

[happy 3345]

thanks for your help this page doesnt help.

 

[Oberloh]

When you use batteries together like that they SHOULD be very similar batteries. Doesn't matter how you connect them because the weakest batteries will charge first and tell the charging system they are charged thus never fully charging the stronger batteries. NEVER mix a deep cycle battery and a standard battery. They MUST match in type and approximate age or you will have issues or a shorter life span than normal for one of the batteries.

Series batteries provide double the voltage... But if you are using 2 batteries of different capacity or age where they are measurably degraded you will never fully charge the good batteries thus reducing their life dramatically.

If you do them in parallel they generally double the storage capacity. But again the batteries need to be similar in type, size and age.

If you decide to use a deep cell battery and a standard battery you must use a digital style charging system or you will reduce the life of one of the two batteries. Which one will depend on their characteristics. Other option is a separate alternator for the deep cell battery.

Thank you for posting this information back in '19. It should save me lot of hassles. I didn't realize that I should use a digital style charging system with a deep cell.

 

[redheadedrod]

Thank you for posting this information back in '19. It should save me lot of hassles. I didn't realize that I should use a digital style charging system with a deep cell.

Only when you use very different batteries. The digital charging systems will allow you to charge each battery on its own as it needs. I may have misstyped when I types what you quoted. The battery that reaches full charge voltage first will prevent the other battery from reaching a full charge. Especially in the newer trucks that have smart alternator. I personally have 2 alternators, 2 batteries.. Resolves any charging issues. One battery for the truck, one for the car audio system.