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Topic: Solar (Read 964 times) previous topic - next topic

Solar

The question is multiple smaller panels or 2 or 3 larger higher voltage panels? May have a deal on a couple of 420 watt panels.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Solar

Reply #1 –
So many variables - hard question to answer.  One (of many) factors to consider: roof accessibility.  When I had our solar system installed, one of my requirements was having enough room left on the roof to be able to walk around safely.  I know not all Forum members want to (or are able to) get up on the roof, but at my advanced age I can still scamper up the ladder like a monkey.  I insisted on being able to walk around up there without (increased) danger due to the solar panels.  Photos below of our panel array, which met all my goals, including "walking around space".

Suggestion: list your priorities in order of importance to you.  Total wattage output, cost, size of panels, number of panels, tilting or not, wiring complexity, ease of cleaning, aesthetics, etc.  Then find the setup that comes closest to being perfect, for YOU.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Solar

Reply #2 –
  If you have a line on a good price for 420 watt PV panels, you should jump on the purchase.
The few 420's I've seen are 6 1/2 feet by 4 1/4 feet in area, and should be no problem to install on your roof with adequate walking room. They all push 48vdc, so will be fine with small diameter MC4 cable.
  The bigger concern will be purchasing the Solar controller. Do not scrimp here. Get the highest quality MPPT controller that you can afford, making sure that it has all provision for the type of batteries you will be using in your bank(s). You will also want to assess the current ancillary system components to make sure that the whole system is fully capable of providing all of your electrical needs without strain while you are boondocking. By this, I mean convertor and inverter.
  The initial cash outlay is going to give your wallet a serious hurt. I went through the hassle of educating myself in order to design my PV system myself. It took quite some time and energy to do that. I simply couldn't afford to pay a professional designer. If you can have someone knowledgeable do the work, then you should go that route. I also had the luxury of having time on my side, and slowly purchased the components a bit at a time. The financial shock was minimal. Batteries, controller and panels were the heavy hitters.
 The whole system was installed and tested before we went for our first Dry Camp out in the toolies, with absolutely NO grid power anywhere near our location. We managed a week without grid power and no generator.  600 amp hours on the house bank and sunny days allowed us to never have to worry about daily usage of either DC or AC power.
  Good luck. Just make certain that you have the whole system well designed before you ever spend a dime on this project. It's easy to end up with expensive items that you can't use.
    Steve
Route 66_End to End....someday

  1986 36' Grand Villa
    2015 Jeep Patriot
        K1SLD Steve
        K9NIK Nikki

Re: Solar

Reply #3 –
Hey Steve, we already have ample batteries, and inverter. Thanks for the advice. You are right one must educate themselves prior to purchasing a solar system as their are folks out there that will help empty you wallet.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Solar

Reply #4 –
Very happy with our 900 watts on roof and 3 *d Lifeline AGMs. Morningstar controller and a second 1000watt PS Inv for whirlpool frig and  TV+stereo and an outlet by driver and counter for charging pads etc. Now about 5 yrs since install and all is well. NEVER use the gen and very few full hookups on our trips. Lowest battery reading of mid 70% I can remember.
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Solar

Reply #5 –
 You mentioned "2 or 3 higher voltage panels".  Are you asking about higher voltage (12 volt vs 24 volt) panels, or larger wattage panels?

Unless things have changed in terms of solar charge controllers (I don't stay up on the latest solar stuff), 24 volt panels put out too much voltage to charge 12 volt batteries without harming them.  You should stay with 12 volt solar panels to match the coach's 12 volt wiring.

In terms of several smaller wattage panels vs fewer larger wattage panels...  Look at the maximum amps each panel generates.  Sometimes you can get more amps connecting two smaller wattage panels in parallel vs using one larger wattage panel.  Then you can run groups of parallels panels to the charge controller.

Don't over size the system if it doesn't need to be.

Also consider designing the system to allow you to have some free standing solar panels.  That way if you ever camp where the rig is shaded under a tree or forest canopy, you can place free standing panels out in the sun.

If you rely heavily on solar, remember to use/exercise your generators to keep them in good shape just in case you need them.

We've had a number of dry camping experiences where our site was socked in with clouds/fog/mist for several days on end, and solar was useless.  During those times nothing replaces a working generator.

Chris

Re: Solar

Reply #6 –
Quote from: Numbers –
You mentioned "2 or 3 higher voltage panels".  Are you asking about higher voltage (12 volt vs 24 volt) panels, or larger wattage panels?

Unless things have changed in terms of solar charger controllers (I don't stay up on the latest solar stuff), 24 volt panels put out too much voltage to charge 12 volt batteries without harming them.  You should stay with 12 volt solar panels to match the coach's 12 volt wiring.

In terms of several smaller wattage panels vs fewer larger wattage panels...  Look at the maximum amps each panel generates.  Sometimes you can get more amps connecting two smaller wattage panels in parallel vs using one larger wattage panel.  Then you can run groups of parallels panels to the charge controller.

Don't over size the system if it doesn't need to be.

Also consider designing the system to allow you to have some free standing solar panels.  That way if you ever camp where the rig is shaded under a tree or forest canopy, you can place free standing panels out in the sun.

If you rely heavily on solar, remember to use/exercise your generators to keep them in good shape just in case you need them.

We've had a number of dry camping experiences where our site was socked in with clouds/fog/mist for several days on end, and solar was useless.  During those times nothing replaces a working generator.

Chris
Things have changed quite a bit Chris. Most Mppt controllers can take upwards of 100 volts. This allows much smaller gauge wiring from panels to controller and allows you to install larger panels. {most larger panels are over well over 12 volts]. You cannot have too much solar power or too much battery capacity. Personally if not using air conditioners, I do not ever have to use a working generator.
That includes one 4 day period where it was cloudy and rainy.
Once the panels charge the batteries to 100% the controller will limit the charge so you cannot overcharge, and of course the more amp hr capacity [batteries] you have, the longer you can go without sun or generator and the more panels you have, the faster your batteries will charge.
JIm
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Solar

Reply #7 –
Jim,

Thanks for letting me know about the changes with the MPPT charge controllers.  Time for us to make a change with our new (old) coach, and for me to clear out the mental cobwebs and come up to speed.  Our setup is old enough that we are using a PWM based controller.  I've just moved it from rig to rig since it kept on working.

What you shared about MPPT and voltages/wire sizes makes perfect sense.

Chris

Re: Solar

Reply #8 –
One point... Morningstar Tristar range of controllers will take an overload. If for example your panels have the ability to put out 60A, you can put their 45A controller in. Then, mornings, evenings, cloudy days the 45A controller goes into MPPT mode before the 60A model, so you harvest more on the shoulder times. You loose some production when your panels are producing their max, which will very seldom EVER happen.
Dave W. (AKA Toyman )
'03, 270, 36', Build 6095, Pulling whatever I hook it to.

"Don't cry because it's over. Smile because it happened."
Dr Seuss
 

Re: Solar

Reply #9 –
Quote from: toyman –
One point... Morningstar Tristar range of controllers will take an overload. If for example your panels have the ability to put out 60A, you can put their 45A controller in. Then, mornings, evenings, cloudy days the 45A controller goes into MPPT mode before the 60A model, so you harvest more on the shoulder times. You loose some production when your panels are producing their max, which will very seldom EVER happen.
Good point Dave,  mid summer, noon, no clouds, south texas, best I ever saw was 980 watts on my 1200 watt fixed array.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.