Question about dual battery system...

[TXtraumaRN]

I installed "Blue Sea Systems Add-a-Battery" and I don't know if I have it wired incorrectly or if it's just not doing what I expected.
When I switch it to "On" it only turns on the "starter" battery and I have to turn it to "Combine" to turn on the second battery. I thought it was supposed to turn them both on from the "On" position and keep them separate until you turn it to "Combine" if needed? I don't want to always run on combine because I would have no emergency back-up of both get drained.
Am I over thinking this? Is there a way around it? A different switch?

 

[HangOutdoors]

You have it wired incorrectly. On turns on both batteries. Combined Parallels batteries if one died, etc.

 

[ellj]

Agree. Wired wrong. One side of switch should be starter/engine. Other side should be your "house" items (gps/nav/fish finder/audio)

 

[marcham]

We need a picture of the back with labels indicating which wire goes where....

Looks like your acr is active, is there a shore power charger as well?