Solar pros and cons?

So lets talk the pros and cons.

Solar is wonderful when the sun shines, not so much when it doesn't. So you need to keep a generator just in case.

Once solar is mounted you may just forget it and let it do its thing. I went from fretting about the battery to checking the voltage once a day. The con is your rig will also have to be in the sun.

Mounted solar will keep your batteries charged and ready to go even in storage. No downside here.

Portable panels are neat because you can position them to best fit your needs and still have the rig in the shade. When we need more power or the clouds reduce output, I can point the panel right at the sun and get every amp possible. in the best of times I can lay it flat for weeks at a time and never move it.
The con for a portable is the need to store it, set it up, take it down, move it to track the sun. Add in worry that it may blow over or be stolen too.

Solar can keep your batteries up but you need to have those batteries to store the power for when the sun isn't shining. Batteries are heavy and they themselves have to be put somewhere. You will need to read up on the different types of batteries, how to set them up and maintain them. Some use so much power that they don't have enough room so the solar can only reduce the run time of the generator.

On solar your batteries can see a higher state of charge than a few hours on a generator. The con is if you use a lot of power, you will need a lot of battery and panel to keep it up. Even more if you have limited sun.

Solar is silent and I haven't found a con to that yet. :)

Solar is getting cheaper all of the time and if you can make do with the lower end controllers, it can be very inexpensive. The least expensive panel per watt are higher voltage and require a more expensive controller. The downside is it is addicting. Even though we have more solar than we need I still drool when I see the ads coming from solarblvd or on craigslist.

Is solar for you, only you will know after understanding some things like how much sun do you get, how much power do you need, do you have room on the roof or a place to store a portable, batteries, and lets not forget what you can afford.

It can be overwhelming at first and it may seem like pulling the string on a generator is easier. Once set up you will wonder why you bring the generator at all. (for back up and AC of course)

AS you will notice when reading the specs of the panels you are looking at most give you the USABLE DC power output current which for a typical 100-120WATT panel is only 5-6AMPS DC CURRENT..

Don't expect this to charge your battery up in a couple of hours...

The battery science is that when you hit a deep cycle battery with 14.4VDC the battery will want to draw a good 15-17AMPS DC Current and if this much power is available the battery will get to its 90% charge state in as quick as a three hour charge time... You will probably run out of sun light before a single 100-120WATT panel will get a single 85-100AH battery charge back up to its 90% charge state when only using 5-6AMPS of current.

In my case my three 85AH Deep Cycle batteries draw around 52-53AMPS when I first start charging them each morning and my PD9260C being run by my 2KW Generator does get the three batteries back up to their 90% charge state with a three hour battery run. I haven't got into the solar panels yet but I suspect I will have to run my generator first for an hour or so to get over the initial large current draw by the batteries then I perhaps can allow my planned two or three 100-120WATTs solar panel to keep the charge going at around 15AMPS or so as the high sun keeps the solar panels going the rest of the SUN DAY. Then perhaps around 4PM or so I will have my three 85AH batteries back up to their 90% charge state so I can use them again the next day/night run off of the batteries.

Just my thoughts on how to address this after discussing all of this among all of the battery/solar experts on here...

My daily use of DC power seems to be around 300WATTs with 1-2 DC AMPS being drawn all day long with my parasitic draw and the 20AMPS or so using an Inverter mainly from 8PM to 11PM each night to run all of our home entertainment items and lights. My 90% charged state battery bank will drop to around 12.0VDC by 8AM each morning doing this when I start my battery bank re-charge using the 2KW Honda Generator connected to the trailer. After my battery drops back from 14.4VDC MODE to 13.6VDC mode then I am pretty sure my solar banks of three 100-120WATT panels or so will get my battery bank back up to the 90% charge state so I can do all of this all over again. This is my plan at any rate hehe... In my case I will have to know around 4PM if my battery bank is back up enough otherwise I run out of time I am usually allowed to run my 2KW generator before generator use time restrictions at most of the places we go expires at 8PM each day. I will not survive the night unless my battery bank starts out at least at 90% charge state.

Just passing all of this on to get your juices going on doing this in a planned and successful way for using solar panels. I don't think you can just stick up a solar panel and run off of it when the sun is out and do anything for your charging your battery bank. Got to look at the long run...

Mother nature would always get after me around 10PM each night when all the lights go out due to battery dropping to zero charge state if I don't start out each evening with at least 90% charge state batteries...

After five or so years now of learning how to do all the things we want to do when camping off the power grid and being successful now of re-charging my battery banks each morning I am just now starting to get in on the solar panel panels.

Takes a bit of planning to be successful about it for me...
Roy Ken

1) Using portable panels is much more efficient, if you keep them aimed toward the sun every couple 3 hrs.
2) If you perm mount them on roof, figure on at least double to triple the panels.
3) Storing/hauling port panels is always a problem unless you have large basement compartments, or carry them inside.
4) Don't get caught up in all the hi $ sofistigated equipment, unless you are a real solar fanatic.
5) Panels at $1.50 per watt max, and a $15 controller works great for me. Add a 100 ft roll of 10ga twin lead wire ($36) to connect it all, and you're in business.

Moved from Forum Technical Support

Hi Rmack1,

Here is a simple flow chart.

The only con is the initial price.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT.

One rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the high the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!

Solar Spread Sheet N8GS

For a nice explanation of solar, try this link:

Golden rules of solar