Advice / Recommendation on solar panels

[Steelhorzz]

I'm looking to purchase and hookup to the batteries a "free standing" solar panel kit to keep my coach's batteries charged when it's in storage.

We rarely "dry camp" so I'm not interested in mounting anything up on the roof.

(Georgetown 360 / 2-12 volt, Grp 31 batteries)

We're in So Cal. So pretty much it's sunny all the time, and I can face them towards the southwest sky all day.

Was wondering the difference between polycrystalline or monocrystalline panels?
Which would be better?

And for just charging batteries, 100 or 200 watt?

I've been researching Renogy brand with with 30 amp controllers.

I have seen some folks in our RV storage area with single panel "kits", add another panel after a few months.

Haven't been able to contact anyone while I've been there to ask them what, or why.

Thanks everyone!!

[boondocking]

In your case seeing as there will not be a shading issue go for either Poly or Mono. 200 watts would be better, a little quicker charge, so the panels don't have to stay outside as long per day.

[SuicideSaints]

mono is superior to poly (due to silicone purity)



If you know you dont want anything bigger or more capability go with the suitcase system from renogy.


If you think you may want more than one panel or a better controller go with their starter kit 100w and upgrade to the LED PWM controller. This controller can handle up to 400W.



I have this system and I have been using it for about 3 months. It more than keeps my batteries charged when my 5er is just sitting there. When camping (I only boondock) as long as I get 3-6 hours of sun per day (depending on my electricity usage that day) it fully recharges me back to 100% each day (I have 2 grp 24 batteries - soon to be 6v this weekend)

[Kaadk]

Question, why not on the roof? From what I've learned from these forums over the years, those that do dry camp/boondock tend to prefer panels they can orientate towards the sun to give them maximum exposure throughout the day, but for a storage lot, I'd think roof mounted might be the better option. You're not really worried about maximum exposure in storage, and with them mounted, you don't have to worry as much about them growing legs either.

If I was going to put in panels specifically for use in a storage lot, I'd be looking at putting them on the roof.

[DanMistyMiler]

Question, and just for my education, why would you need a 100 watt or 200 watt panel just for storage? Why not a smaller panel/solar batter tender to maintain? 100 or 200 seems overkill for that purpose.

[Steelhorzz]

Originally Posted by DanMistyMiller

Question, and just for my education, why would you need a 100 watt or 200 watt panel just for storage? Why not a smaller panel/solar batter tender to maintain? 100 or 200 seems overkill for that purpose.

I guess that's also a good question....
What wattage would I need?
For charging it's all about amperage, so I don't know how wattage relates.
Bring novice to solar, I'm only going by what I see other people have setup in my RV storage facility, and what's offered for sale on eBay and Amazon.

As far as automotive, I've have learned over the years......
"Bigger IS Better"!!

😬

[SuicideSaints]

Originally Posted by Steelhorzz

I guess that's also a good question....
What wattage would I need?
For charging it's all about amperage, so I don't know how wattage relates.
Bring novice to solar, I'm only going by what I see other people have setup in my RV storage facility, and what's offered for sale on eBay and Amazon.

As far as automotive, I've have learned over the years......
"Bigger IS Better"!!

😬

So if you just want it to maintain/trickle charge your batteries in storage and that is it, then a 100w is overkill (assuming your batteries are full when you put you trailer in storage).


Some basic knowledge



watts = amps X volts


1 amp X 12 volts = 12 watts
2 amp X 12 volts = 24 watts


For my trailer I know I have a .25 amp draw with everything off and battery connected.


So to size a panel for this draw I take:


.25 amps X 12 volts = 3 watts


This is per hour, so for a 24 hour period I multiply 3 watts X 24 = 72 watts for a 24 hour period.


When looking at solar panel wattage that means the watts the panel puts out under peak conditions in 1 hour. So a 100w panel puts out up to 100 watts under ideal conditions in one hour.


Similar situation, if I have my battery disconnected it drains at a miniscual amount (something like .009 amps). So, .009 amp X 12 volts = .108 watts x 24 hours = 2.5 watts a day. So a 3 watt panel would top me off in an hour for a whole days worth of drain.


Most tricklecharge solar setups charge/maintain at a .27 amp rating. which is .27 amp x 12 volts = about a 3 watt panel. For maintainging you could easliy get a 3-5 watt panel and put it in a window and you would be fine.


What you are seeing in the storage lot is people probably use those 100w panel out while they are camping and then use them as a maintainer at the lot. I doubt they bought the 100w and controller for storage lot maintaining. Like mine I bought to use camping, just while not camping I can use it for a battery tender/maintainer since my controller is a 4 stage and goes to float/maintenance mode.


I hope this is the info you were looking for and I hope I made it a little easier to understand

[Steelhorzz]

Originally Posted by SuicideSaints

So if you just want it to maintain/trickle charge your batteries in storage and that is it, then a 100w is overkill (assuming your batteries are full when you put you trailer in storage).


Some basic knowledge



watts = amps X volts


1 amp X 12 volts = 12 watts
2 amp X 12 volts = 24 watts


For my trailer I know I have a .25 amp draw with everything off and battery connected.


So to size a panel for this draw I take:


.25 amps X 12 volts = 3 watts


This is per hour, so for a 24 hour period I multiply 3 watts X 24 = 72 watts for a 24 hour period.


When looking at solar panel wattage that means the watts the panel puts out under peak conditions in 1 hour. So a 100w panel puts out up to 100 watts under ideal conditions in one hour.


Similar situation, if I have my battery disconnected it drains at a miniscual amount (something like .009 amps). So, .009 amp X 12 volts = .108 watts x 24 hours = 2.5 watts a day. So a 3 watt panel would top me off in an hour for a whole days worth of drain.


Most tricklecharge solar setups charge/maintain at a .27 amp rating. which is .27 amp x 12 volts = about a 3 watt panel. For maintainging you could easliy get a 3-5 watt panel and put it in a window and you would be fine.


What you are seeing in the storage lot is people probably use those 100w panel out while they are camping and then use them as a maintainer at the lot. I doubt they bought the 100w and controller for storage lot maintaining. Like mine I bought to use camping, just while not camping I can use it for a battery tender/maintainer since my controller is a 4 stage and goes to float/maintenance mode.


I hope this is the info you were looking for and I hope I made it a little easier to understand

Totally understand! Thank you! I'm also curious as to why the people in my storage area have such large units as the solar panels remain there when the coach / trailer is gone. Hmmm ......
Well Im confident I can purchase a smaller unit than I previously thought I would need. I'll do a amp draw test with the master shut off just to see what is "draining" when parked. Then I'll purchase something a tad bit more to keep it charged up. Thanks again!!