Size wire needed from RV Roof to Solar Monitor

[ocnboating]

I have a 2019 5th wheel RV that is prewired for 30 AMP solar system. I have no experience in solar wiring of the RV. I see cables marked for Solar in my battery compartment and wires to where the solar controller is being recommended to be installed next to the main DC and AC circuit panel. My main feed to the RV is 50 amps. I have used 30amp connection many times when 50 amp wasn't available. I have a gas electric refrigerator, gas electric water heater.

Knowing the above how many watts of solar panels do I need, size of inverter and I would like and automatic transfer switch. My understand with a transfer switch I can run on solar during the day and switch to battery and than to shore power once that batteries can't support the load. Current battery configuration is (2) six volt acid batteries wired in series 240 amp hr. The plan is to go with (4) 6 volt batteries.

I have looked at the RICH panels. They have a 400Watt package excluding the transfer switch. The transfer switch I was thinking on using was the Rohs ATS.

Any help and recommendation I can get will be greatly appreciated.

New to RV Solar
Ron

 

[Rocketman]

Is 400w enough solar for the way you use your rig?

What are your future plans for power?

Part of your confusion in your post is you are mixing up the 12v stuff with the 120v stuff. The solar will recharge the 12v batteries, unless you have an inverter it will not do anything to the 120v stuff. Or are you taking about adding a all-in-one power station that will provide 120v power - a solar generator?

The solar system will be a couple (or more) of solar panels (such as the Rich brand you referenced) that connect to a Solar Charger Controller - such as a Victron mppt 100/30 (there are many others). This will connect to your 12v battery. (There will be fuses and shut-off switches too).

Now the real question do you need 400w or 600 or 800 or more? That depends on how you use your rig. Do you boondock for a couple of days or a week at a time or just travel from RV park to RV park and keep plugged in?

I would also recommend getting a Victron Smartshunt. This is a battery monitor. Much better than the three led light one that comes in RV’s. It will track exactly how much power is going out (and into) the battery.

Help us help you by giving us more info.

Just for an example My Dad’s 5th wheel he has three used 250w panels and that provides all the 12v power he needs (he starts the generator if the microwave is needed).

I put a large inverter in my MotorHome and so the 1400w of solar runs all my 12v and 120v needs except the air conditioner.

Good luck with your project

 

[HRTKD]

Does your RV have the Generator Prep package?

In an RV an ATS is typically used to switch between shore power and generator power. You don't need an ATS to run the trailer off of solar during the day and batteries at night. To switch to shore power when the battery state of charge falls below a set threshold requires a smarter inverter than you'll find in most RV's. It can be done, but it's more expensive and complicated. My Victron system has the ability to fire up the generator should the battery get too low. But I don't have it set to use shore power in that case. It may be capable of that, but I haven't investigated it since I'm off-grid 99% of the time.

Regarding the title of the thread, you can get by with the existing wire if the voltage is high enough. I always use a wire gauge calculator to figure out what size wire is required.

Interactive Wire Size Calculator

Battery Chargers, Inverters, Solar Components, and Wiring Supplies for Boats, RVs, and Off-Grid Applications.

baymarinesupply.com

 

[ocnboating]

Thank you both very much for your input. Sorry for any confusion between 12V DC and 120V AC. My 5th wheel does not have the generator prep package, I carry a portable 3500 inverter generator when I plan to do boondocking.
For solar I am happy with a max of 30AMP of AC power. My plan is to go with (4) 100watt panels, 30/100 charge controller, 2000watt inverter.
Also, I would like a ATS that can automatically switch me to my 50amp shore power if connected once my solar panel stop producing power and my battery power is depleted. I believe the Rohs ATS-11kw can do this for me.

As for the wire size I plan to go with the recommended size wire from the charge controller #6 to the 2000W inverter and # 4 to the battery with appropriate brakers in between.

My main question is on the size wire from the solar panels to the charge controller. I want to know if the wire from the roof by the manufacture is large enough.

My other question what happen to the AC to DC battery charged that comes with the RV to keep you batteries charged to use all yout RV DC power. Does this stay in place or is it removed??

Thank You
Ron

 

[Rocketman]

The wire from the solar panels to the solar charge controller is probably fine. I did not see where you said what size it is.

If it is 10awg, it can handle 30amps, the one variable you have is you can put panels is series as well as parallel. So you can put as many panels in series as you want, this raises the voltage on the solar wires and your solar charge controller has to be able to handle that voltage.

I am not sure your posts are verbalizing the transfer switch correctly.

 

[HRTKD]

Also, I would like a ATS that can automatically switch me to my 50amp shore power if connected once my solar panel stop producing power and my battery power is depleted. I believe the Rohs ATS-11kw can do this for me.

With the right inverter, you don't need an ATS to achieve the function you've described. I dug into the parameters in my Victron Multiplus 12/3000 and in the "AC Input Control" section you can set the "Conditional AC input connection" option to the ON setting and the inverter will default to island mode. It will switch to the AC connection based on conditions you set, one of which can be a low battery state of charge.

 

[ocnboating]

Thank you both for your timely reply.

The Victron 12/3000 looks like a great product but way over budget on what I have to spend. Is costs almost as much as my whole system.

I plan to go with the following:
(4) Rich 100 watt poly solar panels wired in series
EPEVER MPT Solar Charger Controller 30 AMP
Renogy 2000 Watt Pure Sine Wave Inverter
MOES ATS 50 amp 5500 watts

As for installed gauge wire coming from the roof I believe it's number 10 that factory installed.

I still need to know what happens to the AC to DC charge I currently have that keeps all my DC powered light and controls and my 12 volt batteries charged. Do I leave this installed install possibly with a switch where I can turn it back on or remove it all together. My auto leveling system requires DC power to work along with my water heat when on gas and also my gas electric refrigerator.

I truly appreciate all the help I can get.

Thank YouTpn

 

[HRTKD]

Is the PV cable actually 10 awg? Even if it's 14 awg, that's probably OK, but what if they cheaped out and went smaller than that?

Those four panels, wired in series will have a Voc of 90.4 volts. The solar charge controller has a Max PV Input Voltage of 100 volts. If you'll be in very cold conditions, the panel Voc could exceed 100 volts. The Rich Solar website doesn't provide the coefficient number to know for sure.

Before you buy those panels, make sure they'll fit on your RV. I had intended to install four 200 watt panels, but when I checked the layout in a CAD tool I could get no more than three on the roof. I switch to two 320 watt panels instead and the layout was much better.

The AC-DC converter should be on a circuit breaker in the RV's main distribution panel. If it's the only device on the breaker then flip the breaker to turn it off.

With regard to the MOES, see this thread:

MOES Dual Power Controller 50A 5500 Watt Automatic Transfer Switch for Off Grid Solar Wind System ATS DC 12V 24V 48V AC 110V 220V QUESTION

Hi, I have a question reguarding this ATS Will Prowse reviewed a while back. The manual states the maximum current of ATS is 50 amps and 1200 Watts max load for my 24 volt Battery bank. Is this true? I dont understand the logic behind this bec the ATS gets AC power from the wall and 120 volt...

diysolarforum.com

 

[jarrelson]

I have a 2019 5th wheel RV that is prewired for 30 AMP solar system. I have no experience in solar wiring of the RV. I see cables marked for Solar in my battery compartment and wires to where the solar controller is being recommended to be installed next to the main DC and AC circuit panel. My main feed to the RV is 50 amps. I have used 30amp connection many times when 50 amp wasn't available. I have a gas electric refrigerator, gas electric water heater.

Knowing the above how many watts of solar panels do I need, size of inverter and I would like and automatic transfer switch. My understand with a transfer switch I can run on solar during the day and switch to battery and than to shore power once that batteries can't support the load. Current battery configuration is (2) six volt acid batteries wired in series 240 amp hr. The plan is to go with (4) 6 volt batteries.

I have looked at the RICH panels. They have a 400Watt package excluding the transfer switch. The transfer switch I was thinking on using was the Rohs ATS.

Any help and recommendation I can get will be greatly appreciated.

New to RV Solar
Ron

Based on the information you've provided, it's clear that you have a prewired 30 AMP solar system in your 2019 5th-wheel RV. To determine the number of watts you need for your solar panels, consider your power consumption and the amount of sunlight available in your camping locations. It's also worth noting that your main feed to the RV is 50 amps, and you've used a 30-amp connection in the past when 50 amps weren't available. Considering your gas electric refrigerator, gas electric water heater, and battery configuration of (2) six-volt acid batteries wired in series, with plans to upgrade to (4) 6-volt batteries, you might consider a solar panel package that includes around 400 watts. Additionally, an automatic transfer switch, such as the Rohs ATS, can be used to seamlessly switch between solar power, battery power, and shore power when needed. For more specific recommendations and guidance, it's advisable to consult with an experienced RV solar professional to ensure the optimal setup for your needs.

 

[chateau_nomad]

The Sungoldpower 3k inverter/charger $825 off Amazon has a built-in transfer switch... essentially a pass-through. As soon as you plug in shore power, the inverter switches off and seamlessly passes the shore power through... and begins charging your batteries if needed. Less than half of a Multiplus, but without all the Bluetooth monitoring... which I didn't need anyway.

Solar charging is essentially independent of power supplied through your shore power connection. There's no "switching" needed - other than a manual PV switch (disconnect panels to work on something). The amps provided by the panels simply get dumped into the batteries anytime there's sun hitting the panels. Your solar charge controller and/or inverter/charger will limit current based on voltage of your batteries.