Phase one 24v RV system

[Grabcon]

This is my first post on this site. I will describe what I have and what I want to accomplish in multiple phases. I also want to maintain part of the existing house battery system.

The vehicle is a 2003 Class C 31 foot motorhome with 30 map shore power and an Onan 4000 watt micro quit generator. The single house battery is charged from the alternator and from a 12 volt converter which is integrated into the existing AC/DC distribution panel. To transfer power from shore to generator I need to unplug for shore power and plug that cord into an outlet from the generator.

Goals of the project are to:

• Have it reversible meaning that I can undo the 24v system easily and put the existing system back in place.
• Use the generator and shore power for charging
• Keep the existing house battery charging from the alternator, but supply no house power from this battery.
• Have a functional 24v system without solar for phase one
• Be off grid for a couple of days without charging.

Attached is a drawing that represents phase one. No specific brand name product is really called out other than the battery.

A couple of notes before you review the drawing and comment. I am not an engineer, the drawing is made from research and discussions with others. Based on my current power usage this system should be sufficient for my needs. I also have not called out a BMS for the battery.

• I am looking for comments as too will this work efficiently?
• Does the design make sense?
• The only long cable run is on the 120AC side. That would be from the AC output to the inverter to the existing AC/DC distribution panel and from the 12vdc output of the 24v to 12v converter to the same panel. All 24v and 12v cables are under 2 feet in length.
• Lastly is it expandable for the addition of additional batteries and solar panels?
• Or any other comments that will help or glaring mistakes?

Other project phases will include additional batteries and solar panels. The goal is to be 100% off grid without the use of the generator.

Thanks for the comments.

 

[HRTKD]

Every DC load/charge wire has to go through the monitor shunt. The way you have the shunt shown in the diagram, nothing goes through the shunt.

There should be a fuse between the the battery and the bus bar.

Does your inverter/charger really charge through separate wires? I thought they all used the same set of wires to draw from the battery as they did for charging the batter. I don't have an inverter/charger, so maybe that's how they all are wired.

Some inverter/charger units, like the Victron Quattro, have AC inputs for both the shore power and the generator, eliminating the need for manually connecting the generator/shore power cables, or for an automatic transfer switch.

 

[Grabcon]

Thanks for the input. Yep forgot the fuse, and the shut needs correction.

The Inverter/charger/auto transfer switch is all one unit, at least the ones I have looked at. My generator does not have an autostart and because of my factory wiring it doesn't make sense to bring both shore and generator to the auto transfer switch. In my case the auto transfer switch would switch power sources from shore power to inverter power when either I am not connected or when shore power or generator would fail.

As far as the actual wiring I will need to wait until I buy a unit. I have not bought anything at this time. I am in the mode of buying once based on the correct fit for the project.

My existing system does not have an inverter, the shore power wiring is connected directly to the AC/DC distribution panel. And literally I need to unplug the shore power plug and plug it into the generator outlet box. Granted it isn't automatic but the effort is so little to unplug and plug in it really doesn't make sense/cents to change.