Solar hookup question

[dallasrules]

I have been working on setting up solar for my older rv and I have most of what I need. Where I am still confused is in hooking the rv into my solar set and the existing inverter in the trailer.

My solar setup is stand alone on the ground. My batteries will be in a 24v configuration. I have a 2000w inverter which I am going to run to a pedistal and plug my shore power in. I was going to let the ac side run the dc side through the converter. Otherwise, I have to have another converter to drop my battery voltage from 24v back to 12v.

I am confused about how the trailer converter works though. I know it will use the ac power to run the dc side and charge the battery that is in the trailer. I don't need that battery, or to charge it. If I disconnect the battery or take it out, will the converter still run the dc items?

I have a 2003 Montana 3655 rl. In my cedar creek, if i disconnect the battery the dc side still functions while on ac power.

I have been told that the furnace fan runs on 12v, but I can't get the furnace to work on dc power in either the Montana or the cedar creek. It does function on ac power in the cedar creek, but the montana has no ac power available at all, so I can't check.

[McRod]

Your AC side is not 24v after it comes out of the inverter. It's 120v. That's what your 2kw inverter is doing (24vDC - 120vAC). The converter at your fuse panel inside the RV will run the DC side if you are plugged into shore power (120vAC - 12vDC). It's more energy efficient to keep a battery in your RV to run your DC stuff though, but it will work as you describe. DC - AC - DC is in efficient. DC - DC is better.

Your converter should have a breaker in your fuse panel...make sure it's on.

Use a portable generator to check the AC power for the Montana.

[dallasrules]

So, are you saying I should keep the battery in the rv that is there and let the converter charge and maintain that from the ac that's coming in from the solar setup?

[McRod]

No, that's basically what your doing now. Just run it from shore power.

[Tom N OH]

You really need a battery in the RV. It acts as a “cushion” for the converter. The converter really isn’t designed to operate high amp draw loads such as slides, hydraulic leveling systems, etc. That’s the way the system was designed. And, if you ever intend to pull the RV down the road, you need one to provide power for the emergency breakaway braking system. That is required by law. It sounds like you intend for it to be parked for extended periods but, IF you want to move it for some reason, you need a battery. Your furnace works on 12v DC power only. The control board & fan are both run on 12v DC. Another relatively high draw item.

[McRod]

Tom, I don't think he is intending to move the RV. When plugged into shore power you can turn off the converter and the RV will be fully functional.

[Tom N OH]

Originally Posted by McRod

Tom, I don't think he is intending to move the RV. When plugged into shore power you can turn off the converter and the RV will be fully functional.

No, you cannot turn off the converter and have everything be fully functional unless he intends to have an outside source of 12v DC wired to the RV. Lots of systems in the RV use 12v DC. Lights, water heater control board, furnace fan & control board, etc all use 12v DC that is provided by the battery via the converter.

[McRod]

I keep mine off, everything works fine.

[Tom N OH]

Converter or inverter?

[McRod]

Converter. I keep it off at the breaker.

[Tom N OH]

So what powers your furnace, water heater control board & 12v lights?

[McRod]

My 12v battery bank.

[McRod]

Converter changes AC to DC. I start with DC and invert to AC.

I am guessing since his DC is the start of his on shore power cycle he will have to invert, then convert, so yeah, your right he will need an on board battery, run his converter, or run a DC line from his on shore batteries. That's the inefficiencies I was eluding to above.

[dallasrules]

I tested both my cedar creek 2004 and my montana 2003 and can't get the furnace to work on 12v. Am I missing something? The work on ac power ok.

[Tom N OH]

What charges your batteries?

[dallasrules]

My batteries are wired for 24v, so if I ran the dc side directly from the battery bank, I would need another converter.

[Tom N OH]

Originally Posted by dallasrules

I tested both my cedar creek 2004 and my montana 2003 and can't get the furnace to work on 12v. Am I missing something? The work on ac power ok.

The furnaces all work on 12v only. If yours won’t work when shore power cord is not plugged in, then you have a problem on the 12v side. Bad batteries, bad thermostat, etc.

[McRod]

I have three charging systems. Primary is solar charge controller. Secondary is inverter/charger. Third is the converter/charger which is rarely needed.

[McRod]

Originally Posted by dallasrules

I tested both my cedar creek 2004 and my montana 2003 and can't get the furnace to work on 12v. Am I missing something? The work on ac power ok.

Dallas, do you have a 12v battery in those units? If you don't have a 12v power source they won't work on DC. They work on AC because your converter is on.

[Tom N OH]

Originally Posted by dallasrules

My batteries are wired for 24v, so if I ran the dc side directly from the battery bank, I would need another converter.

You might be better served to get a 24v input/12v output charge controller, then wire batteries in 12v configuration.