Dual Battery setup

[Kblagg]

What is the correct configuration for dual batteries?  I just looked at mine and noticed that the 550cca Marine Deep Cycle battery was setup as Battery 1 and the 800cca marine cranking battery was setup as battery #2.  The manual says that battery 1 should be at least 750cca.  Were they installed backwards?  I thought I remembered reading on here somewhere that you don't want battery 1 to be a deep cycle for cranking.  

[MLA]

39 minutes ago, Kblagg said:

The manual says that battery 1 should be at least 750cca

The #'s on the switch mean nothing more then differentiating between one bank and the other. Bank 2 can be the cranking and bank 2 can be the house deep cycle. All the draw/loads pull off which ever bank you have the switch turned to. 

[oldjeep]

Some boats like mine have larger wires on one battery from the factory. On my boat that is battery one which is designated as the primary starting battery. 

[Kblagg]

5 minutes ago, oldjeep said:

Some boats like mine have larger wires on one battery from the factory. On my boat that is battery one which is designated as the primary starting battery. 

I just pulled the panel off to check out the wiring on the switch.  The #1 position does have a larger gauge wire than the #2 position.  I think my DC battery is in need of a replacement.  Went ahead and took them both out to be tested.  I'm guessing the DC one is in need of replacement.

[MLA]

10 minutes ago, oldjeep said:

Some boats like mine have larger wires on one battery from the factory. On my boat that is battery one which is designated as the primary starting battery. 

This could be a huge oversight on the part of the engineer. A 1/2/BOTH switch allows for each battery to crank the boat. This means the smaller gauge cable is passing the same current draw as the smaller. Both banks should be connected to switch with the same size cable, and one that ample for the potential load. 

11 minutes ago, Kblagg said:

  I'm guessing the DC one is in need of replacement.

They are both DC, 12 volt variety. 

[Kblagg]

4 minutes ago, MLA said:

This could be a huge oversight on the part of the engineer. A 1/2/BOTH switch allows for each battery to crank the boat. This means the smaller gauge cable is passing the same current draw as the smaller. Both banks should be connected to switch with the same size cable, and one that ample for the potential load. 

They are both DC, 12 volt variety. 

sorry, was referring to DC = Deep Cycle 

[oldjeep]

3 minutes ago, MLA said:

This could be a huge oversight on the part of the engineer. A 1/2/BOTH switch allows for each battery to crank the boat. This means the smaller gauge cable is passing the same current draw as the smaller. Both banks should be connected to switch with the same size cable, and one that ample for the potential load. 

They are both DC, 12 volt variety. 

Could be, but that is how they are set up. And fwiw, the 2 batteries then feed into the output wire on the switch which is the same size as the primary battery cable. All the wires are larger guage than a typical automotive battery cable. 

Edited September 15, 2018 by oldjeep

[MLA]

3 minutes ago, Kblagg said:

sorry, was referring to DC = Deep Cycle 

LOL, gotcha!