Solar panel?

[PHOENIXFLIER]

Our caravan came with a small (13w) suitcase type solar panel, which plugs into the battery via a 12v connector. At rest, it seems to work very well, and topped up the battery today, after playing with the motor mover. However, I am led to believe that it would be gutless if living "off grid" for a weekend in the middle of Farmer Giles field!. My question is, what size panel can I use safely without having to add any additional wiring? I realise that it is possible to overcharge the battery etc. but would rather "keep it simple" at present. Thx. Simon.

 

[Dodger524]

Solar panels are generally used with voltage controllers to prevent overcharging of the battery. The size of panel required depends on the season and load that you intend to place on the battery, only you can determine that.
I suggest that the minimum would be a 60w panel and that a 100w would be much better many motorhomes and boats have much more. The amount of charge is weather/season dependant.
If you used a portable panel then I don't think you would need any additional wiring but if you installed a fixed panel on the roof then you would need a pair of wires from the panel to your battery via the controller.
Solarsunshine is an informative site.

 

[PHOENIXFLIER]

I was thinking about one of these....seems straightforward enough!

[ebay][/http://www.ebay.co.uk/itm/like/60W-folding-solar-panel-battery-charger-car-motorhome-caravan-boat-camping-New/322386314767?hlpht=true&ops=true&viphx=1&_trksid=p5197.c100068.m2280&_trkparms=ao%3D1%26asc%3D20140211130857%26meid%3D0f31bc8dd89f446a9500f92b0cf8d2f5%26pid%3D100068%26clkid%3D3524738049880759889&_qi=RTM2063723ebay]

 

[saint-spoon]

We have an 80w briefcase type panel with built in voltage controller. I plug it into a connector on the battery inside the battery box and it charges. It is fine for four or five days off grid even if cloudy but then we don’t take a telly with us and all lighting is LED.

it depends on what you want to run off the battery and how big you power consumption is expected to be.

I found the friendly Club Solar panel advice page helpful when I was choosing my solar panel.

 

[Tukums]

I use a 150w folding solar panel, does OK for me, keeps battery charged up for long stays off grid, even shorter stays in winter.

Took the croc clips off the panel cable and put on a plug to go into the caravan 12v solar socket.

 

[tentmonster]

What about this one - going to order one myself soon to use next month when off grid for long weekend.

https://www.amazon.co.uk/dp/B00ICE0ES4/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1F3LHIOGSCAHF&coliid=I3LIAAZF2EA1PS&psc=1

 

[Dodger524]

I had considered a portable panel but discounted it on two grounds: (a) security, dare I leave it unattended? (b) I wanted something that would be in operation when the 'van was in our storage site so for me it has to be a roof mounted panel. However I can see the attraction of the portable units.

 

[saint-spoon]

I use a heavy duty bike lock to secure it to the caravan, if they wan't it they will take it but I feel that it's unlikely ona busy site that anyone will take the trouble to cut a bike lock, cut the cable and run off with a large set of panels under their arm. it is the sort of thing that folk notice.

 

[chrisn7]

The least aggro is to bond it to the roof. Wiring connections are ultra simple - 2 wires from the panel to the controller, then two more from the controller to the battery. Some controllers don't like the battery to be disconnected whilst the panel is charging, so adding a switch in the positive line is worthwhile for little effort.

Note there is proper 4 mm solar cable now, not just automotive stuff, plus solar waterproof connectors.

 

[Dodger524]

The least aggro is to bond it to the roof. Wiring connections are ultra simple - 2 wires from the panel to the controller, then two more from the controller to the battery. Some controllers don't like the battery to be disconnected whilst the panel is charging, so adding a switch in the positive line is worthwhile for little effort.

Note there is proper 4 mm solar cable now, not just automotive stuff, plus solar waterproof connectors.

I agree that a bonded panel would be best in the long run, it's permanently available and will keep the battery charged over long periods of non-use.

I'm puzzled by your cable reference what is the difference between 4mm solar and automotive cable?

 

[PHOENIXFLIER]

Based on all the advice, I have ordered a 60w folding panel complete with 10a controller built in for £99.00 brand new.. I like the idea of the flexibility as I have modelling batteries to charge, and I think it will keep us going off grid for a few days easily if we are careful with the battery usage. Time will tell! Thanks to all for your help. Simon.

 

[chrisn7]

The least aggro is to bond it to the roof. Wiring connections are ultra simple - 2 wires from the panel to the controller, then two more from the controller to the battery. Some controllers don't like the battery to be disconnected whilst the panel is charging, so adding a switch in the positive line is worthwhile for little effort.

Note there is proper 4 mm solar cable now, not just automotive stuff, plus solar waterproof connectors.

I agree that a bonded panel would be best in the long run, it's permanently available and will keep the battery charged over long periods of non-use.

I'm puzzled by your cable reference what is the difference between 4mm solar and automotive cable?

The cables are plain black for both positive and negative; the insulation is much thicker than typical thin wall automotive use; there are far more strands of finer copper wire for a given cross section; the cables are marked + and - (the strands are so fine you have to be very careful not to cut/break them).

Those are the physical differences I could see - the cables are marked with some 'solar' specifications so there may be even more to it. The solar connectors are quite different from any others I have seen. A waterproof screw up gland is place over the cable; they require soldering to the metal pins; once inserted into their holders, they can never be removed. Male / female halves allow the panel to be removed from the mail wiring if required, and have internal o rings for waterproofing The panel will come supplied with one male and one female connector fitted to help avoid cross wiring.

 

[thosoneill]

Big petrol generator?

 

[MichaelE]

The difference in this solar cable more to do with its protection. It is double insulated with a fully approved outdoor rubber. Highly resistant to the UK weather conditions and will not degrade over time. A must have if you plan to run cable outside. Designed to last.
To be honest this is for solar installation like houses and buildings , no harm using for a fixed roof installation but not really needed for a portable panel.
4mm is only used if your distance will be over 5mts if not 2.5mm will do.The reason for finer copper cable is flexibility. The connectors i believe are being referred too are MC4's , again these are more for daisy chaining panels together, some panel have tails with these connectors fitted.
The one you are buying from Amazon will be pre wired with standard automotive cable which is fine for what you are doing.
The 100 watt panel will serve you very well and you can adjust to face the sun which will make it much more efficient than a roof mounted one.