Electrically challenged....Help me design a house battery system

[gtbensley]

Im thinking that will give me plenty of life. When I was thinking through my venting of the batteries, I was under the impression vented to the cab area is okay with a sealed battery box, but reading I am thinking it must be external and higher, so thats a whole new challenge I will need to tackle. I can vent through the floor easily but hydrogen is lighter.

Just going to install a basic voltage meter to see what they are at. Nothing special

Also will likely add a blue sea fuse block and feed a fridge and such off that.

 

[patoz]

Sounds good and yes, flooded deep cycle batteries must be installed in a compartment or battery box which is vented to the outside. They need to be sealed and isolated from any space occupied by humans, animals, or other electronic equipment capable of producing a spark or other ignition source. They can not be located in a compartment with propane cylinders either.

Hydrogen is lighter than air so the vent to the outside does need to be located as high in the compartment or battery box as possible, with an air inlet of the same size located near the bottom, to provide good air flow upward and out.

And in case you're wondering, this is from the 2011 Edition NATIONAL ELECTRICAL CODE - ARTICLE 552 Park Trailers - 552.10 Low-Voltage Systems

(D) Battery Installations. Storage batteries subject to the provisions of this Code shall be securely attached to the unit and installed in an area vapor tight to the interior and ventilated directly to the exterior of the unit. Where batteries are installed in a compartment, the compartment shall be ventilated with openings having a minimum area of 1100 mm2 (1.7 in.2) at both the top and at the bottom. Where compartment doors are equipped for ventilation, the openings shall be within 50 mm (2 in.) of the top and bottom. Batteries shall not be installed in a compartment containing spark- or flame-producing equipment.

 

[gtbensley]

So now I am a bit confused. If I disconnect my starting batteries my interior lights do not work, while connected but the master switch turned to off they will work for one minute and then time off. If I have the master switch turned to the house battery, they will stay on as long as I keep the switch on.....BUT the starting batteries must be connected.

So confused as to whats going on. They seem dependent on the starting batteries but will stay on with the house battery. Maybe a relay switches power sources? Or maybe they pull off the starting battery.