Best Solar Power System For New Class A Owner

[research@businessvaluecreation.com]

We have a new motorhome for full-timing and we will be staying in parks with few electrical options. We want solar panels and are trying to decide which solar power system is best, what capacity and who is recommended. The system can be installed in the next two weeks, so an Internet purchase with local installation is preferred.

[wolfe10]

Welcome to the FMCA Forum.

What area of the country are you in? That may help in guiding you to a competent Solar source in your area.

And first thing is to determine your electrical needs (in amp-hrs/24 hours).

In sizing the system, you will need to consider your needs and the REAL output per panel (as opposed to the stated output which is under ideal conditions). Also, normal hours of sun per day where you park. If you are in the Oregon, for example, you will more panels than if you are in Arizona as average hours of sun and sun intensity are different. Shade vs fully exposed camp sites.

You will need a controller (regulator) sized larger than the sum of your panel output.

You will need over-sized wiring for minimal voltage loss from roof panels to controller and from controller to battery bank.

You may also want to look at your converter or charger. Newer high-output "smart" chargers or charger inverters recharge batteries much faster from generator or shore power.

And along with your charger, if you need to replace your house batteries, consider AGM batteries. They are more expensive, but will accept a charge at a far greater rate than wet cell batteries. These last two minimize generator run time when that is your charge method.

Brett

[baby@captaincarole.com]

Hi Brett,

This question also applies to me - new first time rig owner. Live in Denver (300 days of sunshine they say). Will be using it as a live aboard and in the winter traveling south, always trying to chase the sunshine!

Form the the manuals I received I was able to figure out both furnaces are 91 watts & 51 watts respectively; TV 210 watts: my laptop maybe 50 watts; lights 10; satellite dish 30. Know the question is the microwave (1000 watts). It won't run currently off the batteries. and from the online solar calculators it looks like if I enter even a total of 30 mins a day, the calculator show me over 500 watts per day. I have 4 inhouse batteries and two chassis batteries and an inverter installed. and also a 10,000 watt generator. But my summer state park sites are without any electrical hook-ups. The rig is brand new Four Winds Montecito (43').

Admit to not understanding much about how the batteries work with the solar panels. Do they just draw energy as they need from the solar panels? Do the solar. If my microwave needs more watts than what I see on the websites for panel output, does that mean every time I need the microwave I have to start the generator? I understand I need a controller. IS there also somewhere where I can see a wiring diagram of how this all fits together - being a visual learner that would help.

Thanks,

Carole

[wolfe10]

Admit to not understanding much about how the batteries work with the solar panels. Do they just draw energy as they need from the solar panels? Do the solar. If my microwave needs more watts than what I see on the websites for panel output, does that mean every time I need the microwave I have to start the generator? I understand I need a controller. IS there also somewhere where I can see a wiring diagram of how this all fits together - being a visual learner that would help.

Thanks,

Carole

Carole,

In a manner of speaking, yes, the batteries just draw energy from the solar panel as the need. Said another way, the controller regulates the amount of energy the solar panels send to the batteries such that the batteries are not overcharged. Of course, if the solar panel output is less than electrical demand, the batteries will be discharged at the difference in charge rate less discharge rate.

And short term use of the microwave is less dependent on solar panel output than on the capacity of your inverter (which turns battery voltage into 120 VAC). So, energy can be "borrowed" from the batteries to power that high load and then returned to the batteries from the solar panels.

But, if you have to run the generator some to recharge batteries anyway, the best time to do so is when you have a large electrical draw such as the microwave, as the discharge and then recharge process is NOT 100% efficient.

One consideration is to buy an oversized controller (larger capacity than required by the panels you THINK you will need. That way, if you want to add more panels later, all you would buy is the additional panels.

And using solar and supplementing with the generator charging through your converter or charger is perfectly acceptable.

For how your coach is wired, you will need to contact your coach maker-- there are too many acceptable ways to wire it to allow for generalizations.

Wiring of solar is as I described in my first post. Certainly wire access from roof to batteries will help determine wire turns and controller location.

Brett

[baby@captaincarole.com]

Hi Brett,

Thanks you for the great info. Helped me talk to the various RV solar panel companies. I did find one thing interesting when talking to the Four Winds tech rep. He exclaimed "You're wasn't going to mount these panels on the roof was I?" I replied actually I was. He said no they should be mounted on the rooftop a/c units, of which I only have 3 not the 4 I figured I'd need. Every one else says roof mount them and use great silicon sealant and you'll have no leaks.

One more thing, understand it is better to wire them in parallel for more power/efficiency?

thanks,

Carole

[wolfe10]

Carole,

Well, you have talked with one installer you can cross off the list. Panels large enough to do you any good are too large and too heavy to mount on A/C units.

There are solar panels that can mount on the A/C units, but they are STRICTLY to maintain the batteries, WAY too small to charge them while the coach is in use.

And panels are paralleled/seriesed, depending on their voltage (just like batteries) your coach has a 12 VDC system. Panels should charge from 13.2-14.5 VDC.

Brett

[baby@captaincarole.com]

Thanks Brett!!

[jmannett]

Deciding on the size and type of solar system depends on how each individual uses power. And, we all use it differently. If you have not already done your installation, let me know and I can e-mail you a few pages from a guide that can help you size the system appropriately.

Jim Mannett

Sun City, AZ