Running factory vehicle accessories off of house battery only. Isolator? Switch?

[jdkellogg]

This is basically a sanity check for me, looking for someone to confirm my thoughts here.
Using a dual battery setup using something like: THIS

Or using basically any solenoid style isolator in between the starting and house batteries, how are you guys using your factory accessories without draining your starting battery? The positive post on the starting battery goes back to the factory radio and interior lights and 12v interior sockets.

So if I'm parked and my ignition is off and I am using the factory stereo for some music at a campsite, or if I'm charging my cellphone off of the 12v socket in the interior, I am just draining my starting battery.

It seems like I should be looking for more of a manual switch with three positions, one for starting battery only, one for house battery only, and one position for house and starting battery in parallel for charging while driving.

Am I thinking correctly here?

 

[4000lbsOfGoat]

I have separate 12v and USB sockets installed in the cab that are attached to the secondary battery. Those get used when the truck is parked, the factory ports only get used when the truck is running.

We also use a portable, rechargeable speaker for campsite music. More versatile than using the truck stereo and can be recharged when we're driving (or charged from the secondary battery when parked).

So, I guess the long and short of it is that we don't use the factory accessories when we're parked....I even have my interior lights set to *not* turn on when the doors are opened.

 

[jdkellogg]

I have separate 12v and USB sockets installed in the cab that are attached to the secondary battery. Those get used when the truck is parked, the factory ports only get used when the truck is running.

We also use a portable, rechargeable speaker for campsite music. More versatile than using the truck stereo and can be recharged when we're driving (or charged from the secondary battery when parked).

So, I guess the long and short of it is that we don't use the factory accessories when we're parked....I even have my interior lights set to *not* turn on when the doors are opened.

This seems to make sense. Thanks for your input. Still curious to see what solutions others have come up with to completely isolate their starting and house batteries from the vehicle.

 

[4000lbsOfGoat]

In terms of switching I use a Blue Sea ML-ACR with manual control switch. It can be set to "auto" which will link the batteries when the main battery is above 13v (i.e. the alternator is running) and unlink them when the voltage drops (i.e. the truck is off). It can also be set to completely disconnect both batteries or to link both batteries for starting if the main battery is dead - however if you are going to use it this way you need to be sure that your "house" battery has the cold cranking amps to start the motor. If using one of this it is ideal to have perfectly matched batteries.

 

[john61ct]

The power to the stereo system needs to be rewired to feed off House.

I do not rely on vehicle HVAC fans etc systems except while the engine is running.

What else?

 

[4000lbsOfGoat]

The power to the stereo system needs to be rewired to feed off House.

I would not recommend "reconfiguring" any factory accessory wiring in any modern vehicle. Given that all of the electronics are monitored and controlled by computers, these systems are more complex than simply "this wire attaches here and that wire attaches there". The computer is expecting to see certain behaviors and other, unexpected, behaviors can cause trouble.

Any aftermarket accessories should be connected to a secondary battery that is isolated from the factory electrical system.

Portable bluetooth speakers are pretty inexpensive and a lot more versatile than the vehicle stereo....