Just returning to caravanning after a 7 year break...looking forward to going back to our favourite site which is without EHU... we have got a swift Conqueror 630..so if we decided to get a solar panel to help us with electric what should we have ? Central heating ..fridge ..cooking can all run off gas..lights..maybe Tv will want battery power...need something so we can last a week...We had a generator last time but unfortunatley sold it !!!
------------- Coming home back to a caravan
2013
Whit week Kelpie Manorbier
July/Aug Carpenters Farm Isle of Wight
Of course it depends on your power usage habits and the time of the year you caravan.
But assuming you are not expecting it to support you Nov to March and you are not TV addicts then IMO a 55 Watt is the minimum sensible size. Anything bigger is a bonus up to the point where its bulk and weight become issues or you simply cant store its yield in the battery(ies) you have.
We have an 85 Watt free standing unit with two batteries, the caravans 90 Ah and a portable one 60Ah that we take when we know we are going to be using the TV 2 or 3 hours a night. This is quite a big panel so I made a cartridge to house it under the rear of the van. The controller is a Morningstar Duo that services the two batteries in a logical manner.
With our set up this panel is a gross over kill in the summer but becomes marginal in the extreme months of the period I identified and fails to support our true winter needs when we encounter poor weather.
Roof mounting is much less hassle and with a generously sized panel quite suitable for summer use but more quickly becomes inadequate in the shoulder seasons because of the lowering sun angle on a horizontal panel.
Panels are now more affordable than before unless buying at High Street prices so dont set too tight a budget or you could regret it, its not a area to penny pinch IMO.
Post last edited on 15/11/2012 06:50:28
Discounted Insurance Quotes for UKCampsite.co.uk visitors! Up to 12.5% off!
Thank you....there is a bosch 100w portable 2x50w on e bay...£234 i think...not looking into solar power before its all very confusing ...at the moment we are unable to use the van untill about March as car has been changed and new one has no towbar ...but i think after then we will use it all year round...so we have time to look ...all advice welcome.
------------- Coming home back to a caravan
2013
Whit week Kelpie Manorbier
July/Aug Carpenters Farm Isle of Wight
I was looking at panels on eBay last night. They seem to have come down a bit since I fitted ours. They seem to be available at a little over £1 per watt if you shop around. We can manage a week easily with a 50watt panel but if we added a bit more it would be nice to use a bit more power, especially if the weather is not so good which is when solar power is producing the least.
A rough rule of thumb is that a panel will output 3.5 times its rated output per day ie an 80W panel will give a total output of 240W per day on average throughout the year. Summertime is going to give you a bigger output and winter much less. Don't make the mistake that a panel outputs 12V - they are normally about 18V and therefore the amperage will be lower than you may expect. A twin battery solution is a good option in the winter months as it gives you a bit of leeway should the weather throw low light levels at you for a few days running. May favoured option in the winter is two 80W panels and two batteries plus a lot of gas to heat the caravan.
I used to use a Rutland wind charger as well as a solar panel. It was a handy little thing for topping up the battery when the light levels were low but tbh it is too much bother to fit it up on a mast and feed back to a controller. Old age is making me lazy... They are great if you are going to be in one place for several days. The cheap Chinese wind chargers are not a lot of use as they have a high starting speed and don't work at all well in gusty turbulent conditions as normally found within about 5m of the ground.
Of course you can ignore all of the above and chance that your battery might last just long enough. The above is what I have found out from using pv and wind power for the last 20 odd years but your experience may vary considerably depending on where you are and your pattern of use etc.
------------- 'A sure cure for sea-sickness is to sit under a tree'
if you haven't already, changing to LED lighting is a good start.
Was away at half term, and thought right, Ill not use the charger, and see how I go.
Took 5 days to get to touching the top of the orange on the meter under load.
Thats with a 110Ahr using CD player, lighting etc.
All my lights are LED, bought off ebay from hongkong, only had 2 out of 10 fail in 18 months.
Quote: Originally posted by birder99 on 15/11/2012
Don't make the mistake that a panel outputs 12V - they are normally about 18V and therefore the amperage will be lower than you may expect.
However if you use decent quality solar controllers they will be very efficient and feed the battery with the required voltage for its state of charge and modulate the amperage as required.
Therefore the current out of the controller will be higher than the current in from the solar panel.
I have on various occasions measured 82 Watts going to the battery from my 85 Watt panel via my two different Morningstar controllers. Never seen the full 85 though.
Its a portable one 2 x 50 and weighs 12kg...on ebay..sorry not sure how to link it ...but item no 120921727453 and controller is10A Photonic Universe solar charge controller included with the kit will protect your battery from over-charging. It has many other protection functions, such as stopping reverse current at night (from the battery back to the solar panel) and incorrect polarity protection. The controller uses PWM (Pulse Width Modulation) technology which increases charge acceptance and prolongs the life of your battery. PWM technology can also recover some lost battery capacity...hope this makes sense..
------------- Coming home back to a caravan
2013
Whit week Kelpie Manorbier
July/Aug Carpenters Farm Isle of Wight
"Pulse Width Modulation" controllers are fine, not the very best but cost effective. Given the panels output is more than adequate then the controller type not being quite the most efficient is not a real world issue. As for the controller makers reputation I have no idea.
The packaging with the controller appearing to be stuck to the rear of a panel is convenient but technically "naff". This is because controllers ideally need battery temperature compensation and the expedient way to achieve this is to place it very close to the battery so it is sensing the same temperature as the battery. Locating it near the battery also better handles compensation for wiring losses. Putting it on the panel is not good as panels get very hot in service so if the controller does feature battery temperature compensation then that function is getting completely screwed up info.
However as said locating it there is nice and convenient for the packager and involves no effort on the user so many would consider its technical failings tolerable.
The system's use of Anderson connectors is very good and though I don't know about Bosch panels I do know that as a company they have a good reputation.
Looks an appealing package for the money and convenience.
Edit: In use place the panel on a board or sheet or some similar way to make absolutely sure that no shadows from blades of grass etc fall on the active cells. Avoiding shadows makes a massive difference to the panels yield, completely out of proportion to the % of shadow. I see many panels plonked straight on the ground in all the grass, the owners oblivious to the fact they are destroying the panels potential yield.
Thanks John
Ok then if you was in the position of buying a solar panel to use for topping up your van ..what would you consider appropriate and good value for money...in the end i dont want something thay doesnt do its job properley ..what would you buy ?
------------- Coming home back to a caravan
2013
Whit week Kelpie Manorbier
July/Aug Carpenters Farm Isle of Wight
The one you found and we discussed is quite appealingly packaged and nicely hassle free, so if not a technical nerd I would go for that. Its convenience and hard case being its selling features.
I went to a great deal of trouble buying a very high quality Kyocera panel and making a stand that folded within its frame plus a plywood box that fitted under the van to carry it. I original purchased a Mornigstar PWM 10 Amp controller and a couple of years down the road change to a Duo Morningstar with meter feeding both the vans battery and when needed a second portable battery. I spent twice what you are looking at but things then were a lot dearer. I need my system and would buy the same sort today but I put no value on the time I spend fiddling about and researching, as I said a bit of a nerd. Go for what you have found its good value and adequate; possibly move the controller one day if you feel the need to be technically improving things a bit.