Small solar panel suggestions.

[Colin A]

So sort of boat related. I have played with several smaller panels on boats over the years (10-50W) Mostly cheap ones from ebay or clearance sale specials. Wondering if any one had any preferred brands currently? The last couple I have used were (that had brand names at least)Solara and Ganz semi flexible units, which worked OK but I have a new application where a framed unit may be better.

My in laws have a 5th wheel camper that spends most of it's time hooked to full service campsites. But recently they spent several weeks off grid and of course had battery issues. (before this with this camper at least they hadn't gone longer then 2-3 days off grid). The battery is only running the lights and waterpump and the occasional vent fan. But a big 5th wheel has a lot of LED lights. So the single group 31 started dying by early morning. The have a Honda 2000 they use for charging but only use it 2 hours at a time. I looked at the camp sites they were staying at and solar seems to be a real possibility but they don't really want permanent mounted units for a few weeks of the year they don't have a hookup. So I was thinking of taking a couple framed units and making a little suit case unit that can prop up on the grass with a quick connect to the camper with a controller. I think two 50 watt panels might make a good start while being easy to handle.

Any thoughts on brand would be appreciated. (yes I know you can buy ready made folding panel kits but the pricing seems steep based on component cost.)



On a side note to the topic of partial discharge and killing batteries. I checked out the battery over the weekend and discussed how they used it (3 year old Interstate). So after being constantly plugged in for 2 years. They started off using it off grid and it was fine for the first week then declined the next two weeks to the point where a low voltage buzzer went off in the middle of the night. It appears the buzzer was set at just under 11 volts and had gone off several times before they started charging. Pretty sure 3 weeks of near dead plus limited charging (they plugged the camper in for a while between week one and two) killed the battery in under a month of real use. (the only charge indication was 4 LED's that read empty at less then 11V 1/3 at 11.6 2/3 at 12.1 and full at 12.7. so basically useless)

[FLYSolartech-GiocoSolutions]

Hi Colin,
As you said there are million chinese cheap panels on EBAY, but if you want a good product I suggest you FLY Solartech (yes the company that I work for) ,GiocoSolutions , Solbian.


Ps, I suggest you to read this 2 topics>
http://www.cruisersforum.com/forums/...ml#post2701357


Italian Solar Semi-Flexible panels - DISCOUNTS for Cruisersforum users - Cruisers & Sailing Forums

[smac999]

if their 2000w gen for 2 hours a day can not keep the battery alive.

how do you expect a 100w panel for ~6 hours a day to do anything? it would need 40 hours per day of direct sunlight to match the same power output as the gen.

most likly they have a tiny battery charger and are not utilizing the gen. first thing to look at is that. replace the single battery with a pair of AGM batteries. and make sure the charger is in the 60-80a range. to maximum the gen running. also make sure the battery charges when the vechical is running / moving. and get a digital volt gauge installed. it should never go below 12v.

[a64pilot]

Yeah it’s battery bank size and likely health that is killing them.
However I would not suggest an AGM bank, good ole golf cart batteries are best.
My charger wasn’t adjustable and wasn’t even separate, it was part of the electrical panel that had both AC and DC fuses, breakers etc. I am sure it was not a three stage charger, it may have only been 30 amp or so.
I had four large batteries in my fifth wheel, I can’t imagine only one?

My bank charged off of the truck too, that took installation of a fuse in the tow vehicle to power that wire, if you don’t have the “towing package” you may not have the wiring harness.

You can’t beat the little Honda, maybe get a better charger and more batteries.

If you want to go Solar, mount a decent sized array on the roof permanently, a Kilowatt ought to be easy on a 5th wheel, but again, you can’t beat that little Honda for power output

[thinwater]

I will never understand running a generator in the great outdoors. Might as well stay home. Just my opinion.


I'd cover the roof with semi-flexible solar. Yes, you could do something that folds, but I doubt it would be cheaper or last longer, since folding and moving invites damage. Just get cheap panels and mount them where they won't get stepped on.



And expand the battery bank. Enough for a few cloudy days.

[Stu Jackson]

Wasn't sa guy named something like Battery Bob mentioned sometime ago? He did a nice RV writeup with good basic information bout batteries that even your family would understand, no disrespect intended at all.



Here it is:


https://handybobsolar.wordpress.com/...battery-power/

[Nicholson58]

Originally Posted by Stu Jackson

Wasn't sa guy named something like Battery Bob mentioned sometime ago? He did a nice RV writeup with good basic information bout batteries that even your family would understand, no disrespect intended at all.



Here it is:


https://handybobsolar.wordpress.com/...battery-power/

Handy Bob wrote the Bible I studied before installing my solar. He is a long and tedious read but lots of good advice.

[darylat8750]

Another thumbs up for Handy Bob.

[Colin A]

Yeah should clarify further. I'm well aware of all the issues with the setup. Been working in Marine electrical about half my life at this point. Just haven't dealt with buying solar panels much in the last few years.

So they have a single Group 31 battery around 105AH capacity. The converter/Batt charger (RV thing integrated as mentioned). is a 45 amp unit. That will provide more power then the Batt will be able to accept. The trouble is running at 2 hours they aren't getting that full do to the acceptance dropping off. Adding the ability to add 7-8 amps of solar for a few hours a day would help with that. But no it would not solve all the issues. The battery is 3 years old and has been on the factory converter which as mentioned tend to be awful (have not looked up this one yet. ) My guess would be if they get a little better about leaving lights on they could make the setup work a bit better for the week or so a year they don't have shore power (versus the several months a year they use the camper connected to shore power.) I'm also suggesting they either switch to a pair of GC batts or switch to two group 31 Batts (due to issues with the battery box fitting GC).



All that said the fridge is on Propane (thou it does draw 12V for electronics etc) and they don't have an inverter so my back of the envelope calcs show they should be running around 35-45 AH out of the battery each night. So in theory the single battery should work, but the not recovering is shortening it's life, which a smaller solar setup would help.



Part of the reason they are reluctant to upgrade is I advised them on a previous smaller trailer and they made custom brackets to hold a pair of GC batteries put a small 40W solar panel on the roof and a better charger. Then sold it less then a year later without getting any of those improvements back in resale value. Also on the roof mount panels they camp mostly on the East coast and upper midwest. Most sites they stay in have a fair number of trees. In my experience up here you are often better with moveable panels to find the sun rather then the roof.

[rgleason]

I was able to fit 2 GC2 into an oversized group 24 box, but 2 G31 will not fit, they are bigger, longer, and require a different box!

Framed monocrystaline are more efficient and cheaper. Why not rig them on the roof to be adjustible in one access with a line or line and pulley?