Charging house batteries with solar

[AJMike]

I looked at the specs for the solar panels that came installed on my Fuse and they are rated at 17 volts. I assume that they have to operate at a higher voltage than the house batteries to insure that they charge the batteries, but exactly what should the house battery voltage be?

The electronics panel in the RV show the house batteries at 13.9 volts when the panel shows them as fully charged, but I thought they were 12 volt batteries. What is the highest voltage they can hold? What should the voltage be? And how low can the voltage go before they will no longer keep the RV appliances like the refrigerator working? The refrigerator in the RV is a DC only fridge, so this is of some concern to me.

[BobC]

Pretty much all you want to know about batteries, and more, can be found here:

https://www.solar-electric.com/learn...ery%20Charging

I'm not familiar with your solar installation but this may help:

http://confusedrv.blogspot.com/2016/02/fuse-solar.html

[AJMike]

Originally Posted by BobC

Pretty much all you want to know about batteries, and more, can be found here:

https://www.solar-electric.com/learn...ery%20Charging

I'm not familiar with your solar installation but this may help:

The conFUSEd RVer: Fuse Solar

Thank you. There was a wealth of information at those links and it has answered many of my questions.

[luvlabs]

Twelve volt batteries, when fully charged, will be 12.6 - 12.8 volts. When you see 13+ volts, you are seeing what is known as a surface charge. Let the batteries sit for a while without any loads or additional charge being applied and they will settle down to the full charge numbers.

You will see charging voltages in the 14V range when the alternator or solar cells are charging the battery. When being charged by the converter, you we see voltages more like 13.7 - 13.9.

Your refrigerator will run fine but you need to recharge your batteries everyday - either 200 or more watts of solar, using solar and the engine alternator driving to another destination, or plugged into shore power.

You can also improve your situation but upgrading your batteries to true deep cycle batteries. 2 - 6V golf cart batteries are one popular option.

[AJMike]

Originally Posted by luvlabs

Your refrigerator will run fine but you need to recharge your batteries everyday - either 200 or more watts of solar, using solar and the engine alternator driving to another destination, or plugged into shore power.

Are you saying that the solar alone will provide enough charge to run the refrigerator for several days? Or that I will need to provide some extra charge like driving the RV or running the generator every day?

Originally Posted by luvlabs

You can also improve your situation but upgrading your batteries to true deep cycle batteries. 2 - 6V golf cart batteries are one popular option.

So 2 6V batteries, wired in series, would be better than 2 12V batteries wired in parallel?

How does that work with a 12 volt solar system? Or does the controller need to also be replaced?

[BobC]

Two 6v golf cart batteries in series will be better than two 12v batteries in parallel if the 12v batteries are the "marine" type batteries normally found in RVs. These are a combination starting/deep cycle batteries. Less common, and more expensive, true deep cycle 12v batteries will be similar to two 6v batteries. Here's some info:

https://rvshare.com/blog/pick-best-rv-battery-read/

The controller doesn't care. All it sees is a big 12v battery in either case.

Only experience will tell if your solar can keep up with your refrigerator along with everything else. You can do all the calculations you want but there are too many variables, including weather, panel to sun orientation, usage, etc. You may be OK for one trip but not on the next.