Solar for RV

[Captmaddog]

I have a 2013 Itasca Meridian 34B motor-home that I am wanting to use solar power for dry camping. It has a 6 battery (group 31 AGM) bank that runs everything but the air conditioning units. Almost everything on this motor-home is electric. Fridge is residential electric fridge. Only gas is the stove and furnace. I can run everything on 30 amp plug in including 1 A/C. My question is how much solar panels would I need to keep the batteries charge and would I go directly into the Inverter/Charger or connect up directly to the batteries with an additional controller? Any help is appreciated as I am completely new to solar. Also Probably should say I have a 2800 watt inverter installed and an automatic dual battery charge with the inverter.

 

[GLC]

First you need to find out how many amps are pulled at one time? Or watts? That will tell you where to start as far as the inverter you will need, then the battery storage that you will need and the the solar panels that you will need to charge the batteries. If you go with just the 30 amp info, you will need 3600 watt inverter at least, then you will need to know what is the start up amps or in rush of amps to start things like the AC.

 

[Sirtate]

As mentioned, 30a of shore power is 3600W of power...
A power audit is the fancy term to describe figuring out what you want to run, and how much power it needs..
Things to think about;
- do you want/need to run the A/C? (thats a biggie)
- what about a microwave or toaster?

without those loads, you really don't need much to keep up with the fridge.
I have a 12v compressor fridge in my RV, it draws about 1000Wh per day, according to my battery monitor. (Do you have one of those? inexpensive ones can be purchased on Amazon for ~$100. This may go a long way to help you figure out how many panels you need.)

Assuming your fridge draws a similar amount of Watts, although at higher voltage, 400W of panels is enough to keep ahead of my fridge and charge the batteries (150Ah usable) in about 4 hours.

I would just buy a charge controller with room for expansion (don't buy a 25a controller for your 400w) when you buy the panels (leave room for double the panels) and wire that controller up directly to the batts...

 

[Rocketman]

Here are the details from my MotorHome (2000 Dynasty 36’). We full-time.
I have a Victron Multiplus 3000 inverter, and now have a residential fridge. I have a DIY 540ah lithium battery with a Batrium BMS.

I have 2 solar arrays- (put in at different times) - they both go directly to the battery busbars.
Four 200w panels (2s2p) going to a Victron mppt 100/50.
Two 210w panels (2s1p) going to a Victron mppt 100/30.

These usually provide all the power I need. Usually the batteries are full by 2pm. However, winters in Az, I need to tilt the panels. If I park under trees, or it’s a heavy stormy day, the batteries will not fill up. Then I run the generator for an hour or so - if needed.

I use the microwave without limits, sometimes when I use the convection oven part of the microwave, I need the generator & sometimes I don’t - depends on the solar day and if we also need the A/C on to keep the rig bearable.

So 1220 watts (or so) is what works for us. We still need to run the generator occasionally, but oftentimes I don’t need to run it between the monthly scheduled maintenance runs.

I had the 800w array and it worked great on a trip to Alaska, (but we did use the generator more). Then we went full-time, added the residential fridge and the lithium battery and the second solar array.

I usually use just under 5kwh per day.

Good luck in your journey.

 

[Rocketman]

One other item, the Victron Smartshunt (or BMV712) is the best item I have added on my electric setup. Let’s me know exactly what charge level my batteries are at! (There are other ones too).
A shunt based battery monitor is priceless!

 

[John Frum]

I have 2 solar arrays- (put in at different times) - they both go directly to the battery busbars.

You mean no solar charge controllers?
How does that work?

 

[Rocketman]

Sorry for my non-understandable native tongue.

What I meant to say is…
The solar panel array goes to a Victron mppt, the mppt goes to the main battery bus bars. My main battery bus bars are two bus bars Attached to the side of the battery bay.

 

[Captmaddog]

As mentioned, 30a of shore power is 3600W of power...
A power audit is the fancy term to describe figuring out what you want to run, and how much power it needs..
Things to think about;
- do you want/need to run the A/C? (thats a biggie)
- what about a microwave or toaster?

without those loads, you really don't need much to keep up with the fridge.
I have a 12v compressor fridge in my RV, it draws about 1000Wh per day, according to my battery monitor. (Do you have one of those? inexpensive ones can be purchased on Amazon for ~$100. This may go a long way to help you figure out how many panels you need.)

Assuming your fridge draws a similar amount of Watts, although at higher voltage, 400W of panels is enough to keep ahead of my fridge and charge the batteries (150Ah usable) in about 4 hours.

I would just buy a charge controller with room for expansion (don't buy a 25a controller for your 400w) when you buy the panels (leave room for double the panels) and wire that controller up directly to the batts...

Thanks. That sounds good