solar panels

[ike]

Hi Folks

We've seen a lot of caravan users recently with mobile/freestanding solar panels. We are MH owners but are considering buying a solar panel but don't really want to have one fitted permanently to the roof. I'd appreciate any info from caravan (or MH owners) who've gone down this route. There seems to be such a range out there. Big price differences too. We have two leisure batteries an 85w and a 115w connected in parallel. Does this make a differnce to the size of  panel we need. Our needs are that our batteries be kept topped up to a level that would allow us to camp without hook up for say 2 weeks (or more) if possible. Our usage is fairly light eg lighting at night for 3-4 hours in winter, TV for maybe 1-2 hours a night and in winter be able to run our gas blown heating for as many hours as the cold dictates. I'm technically inept so please bear with me if these questions demonstrate a high level of ignorance!

regards ike

[Terrytraveller]

Hi Ike,

In summer time you will probably manage with a single 80 or 85 watt panel and one 110 amp battery. In winter time you will need two panels of that size and two 110 amp batteries if you are remaining static for a fortnight or so. The advantage with a campingcar is you can go for a little bit of sightseeing and top up the battery charge at the same time.

We extensively toured Europe in our Autocruise camper from May to November for a couple of months at a time, never staying on sites with EHU, mainly using aire d services, remaining static for up to a week at a time and always had enough 12 volt power. We had the satellite TV tuner on all day, listening to BBC radio programs, and the TV on all evening plus all the camper services, usually the battery was fully charged again by 10 in the morning during the summer, and the roof mounted solar panel was generating enough power for the camper services, satellite etc. as well as charging the battery during the day.

 

We changed back to a caravan this year, and have just returned from a C&CC THS at Down Thomas Plymouth 24 day stay, saving £120 by not using the Caravan Club site adjacent to the Camping & Caravan Club, Temporary Holiday Site, the single roof mounted 80 watt panel and Elecsol 110 amp battery, providing enough power for the essential soaps viewing and van services, with the exception of the microwave, toaster and electric kettle of course.

 

All attendees on site had either 50 to 100 watt roof mounted solar panels or 10 to 45 watt suitcase type solar panels, some even had the large 80 watt panels normally roof mounted standing on the ground in brackets, all of the free standing solar panels were either chained or PVC covered steel roped and padlocked to the caravan/campingcar chassis.

 

There are a few different types of 80 watt solar panels and it would be worth while looking at them on Ebay. My first one I fitted on the camper was a Polycrystalline around £400 as a complete kit, solar panel, controller, wiring solar panel mounts etc..

https://live.staticflickr.com/2524/3934965586_493d9b4d2c_z.jpg

The second one is a cheaper Monocrystalline 80 watt panel about £160 and an £18 controller, I fitted the whole thing for under £200 and it seems just as usable as the £400 kit.

https://live.staticflickr.com/4052/4588802908_caa5a1a604_b.jpg

 

Rather than buy another 80 watt solar panel and an extra 110 amp Elecsol battery, I have decided to go down the petrol generator root for the unlikely times I will need extra power, and will only carry it when I know I will need it.

http://cgi.ebay.co.uk/NEW-KIPOR-IG-2000-Petrol-Generator-Brand-New-SILENT-/120595859607?pt=UK_BOI_Industrial_Tools_Generators_ET&hash=item1c1412c897

 

Hope the above helps Ike.

 

Regards Terry

 

[ike]

Terry Thanks very much for your reply- very helpful. I had posted a similar query on the MH forum - not a cheep from anyone!

Cheers ike

[Ocsid]

Terry has given an excellent guide with ratings etc that I would endorse.

I will add my findings on the mobile/freestanding solar panels "ike" has observed as that is the route we have taken.

I have an 85 Watt panel.

 

First they are a curse in that they need putting out, taking in, moving about, transporting, making sure grass does not throw shadows and making secure.

So why do we choose this option? Well it all revolves around wanting as good as possible performance in the winter and the close shoulder seasons when the sun angle is always low. Then it being horizontal inflicts a significant penalty at a time when both the available energy is low and the demand is high.[ because of the extended darkness and need for heating]

However to get that extra does involve a hell of a lot of moving it during the daytime and hence ties you on site. Plus there are days where whatever you do there is little to be had.

 

During the summer I generally simply lay it on the ground as the sun angle is high for plenty long enough to top the battery and basically I can leave it unattended and enjoy my day without attending to the panel.

 

I do however find one problem I did not fore see, it attracts flies and these have a totally disproportionate effect on the cells output. Thankfully most summer days offer enough yield despite these little spoilers. I expect on the roof at the higher elevation this problem would be somewhat less anyway.

So unless you really need to use it during the winter I would certainly recommend leaning towards putting it on the roof. Just make sure you park where it will get sun for a good bit of the day, and you can keep it clean.

[skysurfer]

Thanks Terry for your excellent advice.

I have a slightly different situation as I have a static van on a farm site which has no mains electricity.

I have bought an 80watt panel and am told I need a controller or is it a regulator and some special cable to connect to my 110 leisure battery.

As my van is static I gather it would be advantageous for me to somehow mount it at a suitable angle facing south and somehow ensure it doesn't get stolen when I am away from the van which I use probably for a couple of days each week. I've thought of mounting the panel on triangular brackets and then screwing them to wooden lats which I would stick to the roof (as I don't really want to screw into the roof because of the danger of leaks).

Advice on any of this would be appreciated.

 

Of course I could give up the solar idea and simply keep the battery charged by taking it home occasionally. But I've already put my back out carrying it and am a cancer survivor and pensioner so I thinking of ways to keep the battery topped up without wrecking my health.

Is there any sort of device like the booster mechanics use to get cars started with dud batteries, which I could charge up at home and then plug into the caravan battery to charge it up?

 

Thanks for any help offered...

[Guest 1footinthegrave]

ike - 2010-09-07 1:09 PM

Hi Folks

We've seen a lot of caravan users recently with mobile/freestanding solar panels. We are MH owners but are considering buying a solar panel but don't really want to have one fitted permanently to the roof. I'd appreciate any info from caravan (or MH owners) who've gone down this route. There seems to be such a range out there. Big price differences too. We have two leisure batteries an 85w and a 115w connected in parallel. Does this make a differnce to the size of  panel we need. Our needs are that our batteries be kept topped up to a level that would allow us to camp without hook up for say 2 weeks (or more) if possible. Our usage is fairly light eg lighting at night for 3-4 hours in winter, TV for maybe 1-2 hours a night and in winter be able to run our gas blown heating for as many hours as the cold dictates. I'm technically inept so please bear with me if these questions demonstrate a high level of ignorance!

regards ike

Why not have it permanently on the roof, it's the ideal place, mounted with Sikaflex, and a special roof cable entry gland the jobs done, otherwise are you going to feel able to go off and leave a free-standing panel out, not to mention the hassle of such a large glass item to store and faf around getting it in and out, and in the lighter days of the year are you really going to wake at 5 am to put it outside... You should according to all the perceived wisdom if you are having two batteries hooked up then same make and capacity, preferably new ones id the way to go. Go for a Mppt solar controller as well, that will ensure you get the maximum efficiency from the panel, even on a dull day.

[JaredDesoto]

ike - 2010-09-07 1:09 PM

Hi Folks

We've seen a lot of caravan users recently with mobile/freestanding solar panels. We are MH owners but are considering buying a solar panel but don't really want to have one fitted permanently to the roof. I'd appreciate any info from caravan (or MH owners) who've gone down this route. There seems to be such a range out there. Big price differences too. We have two leisure batteries an 85w and a 115w connected in parallel. Does this make a differnce to the size of  panel we need. Our needs are that our batteries be kept topped up to a level that would allow us to camp without hook up for say 2 weeks (or more) if possible. Our usage is fairly light eg lighting at night for 3-4 hours in winter, TV for maybe 1-2 hours a night and in winter be able to run our gas blown heating for as many hours as the cold dictates. I'm technically inept so please bear with me if these questions demonstrate a high level of ignorance!

regards ike

Well portable solar power panels have got very popular in recent times..Even I have got them for my camping activities..

[royhorn01]

Hi,

 

I bought a 20W panel this year, just for summer festivals. When I get on the field I tape it to my motorhome roof with a bit of duck tape. trail the lead down and into the battery box connect up and I am topping up in the bright summer sunshine. on sunny days it will fully top up the light use for a shower, water pump, some lights and charging phones etc.

 

We are switching to a caravan with a solar panel fitted so I no longer need it.

 

It is still in its box with an extra long lead and water proof coupling. for sale in accessories.

[Electric Cooler Box]

Bit late in offering advice on this one - however a simple method to find out the right solar panel for you, is to go on holiday with a fully charged battery and don’t connect it to an electric hook-up or recharge it and see how long it lasts before the battery is flat.

 

On the battery there will be the rating of your battery marked in Ah, normally caravan batteries come with either a 85Ah or 110Ah battery, but check to make sure that the battery capacity is.

 

So if your battery lasted for 3 days and it was a 85Ah battery then you used 28Ah per day (85/3 = 28). This is not an exact science, but gives an indication to what you power consumption is.

 

You therefore need a solar panel to trickle charge you battery by 28Ah per day during sunlight hours.

 

To calculate the size of panel you will require then battery capacity x voltage = Energy

 

28Ah x 12V = 336Watts, assuming there are 8 sunlight hours in a Summer’s day 336/8 = 42Watts per hour are required, so a 60Watt panel would suffice 8-)

 

Okay so perhaps you don’t want to flatten your battery, so how can you work out the power consumption in your caravan?

 

Your main light in the caravan is a fluorescent strip type with 2x8W tubes, therefore 16W in total. The voltage in the caravan is 12V, so to work out the ampage is Wattage / Voltage = 16W/12V = 1.3A. If the light is on for 5 hours per day then that is 1.3A x 5hours = 6.6Ah (Amp Hours) required per day.

 

If you have a fully charged 110Ah battery, then just using this light for 5 hours per day the battery will last for 110/6 = 17 days.

 

16W x 5 hours = 80Watts needed to re-charge battery each day, assume 8 hours of sunshine per day in Summer then 80W / 8hours = 10W per hour is required from your solar panel. So a 15-20W panel will do

;-)

[Dave C]

If you take more than 50% of the rated capacity from your battery you WILL very much shorten its life so beware.

 

 

 

Dave C

[mrbigfeet]

My experience with solar panels is that the rated watts is at the panel output voltage of about 21 volts. You are charging a 12 volt battery so you have to derate the panel output. A 100 watt panel will give about 60 watts of useful charge. Consider a mppt charge controller. These improve things slightly.