Solar panels. Are they cost effective ?

[John Keats]

The cheapest and simplest way to re-charge batteries is run the engine.

 

Do panels produce a high enough charge to compensate for normal living ?

 

What size. What weight. What cost. ?

 

To be free standing and portable ?

[davenewellhome]

Hi John, solar panels are a bit like refillable gas cylinders in that it takes a long time to recoup the cost of them but they are a great convenience, especially if you do much camping away from EHU. If your panel is large enough and you get enough sunlight falling on it then yes it can produce enough charge to compensate for "normal" living, whatever that might be. Most people go for a roof mounted 85Watt or bigger panel to ensure sufficient charge from the panel. A smaller panel can give the same amount of charge if it is constantly pointing at the sun but the technology to do this automatically is a bit expensive. The alternative is a free standing panel but then you have to periodically move the panel to ensure its pointing at the sun. There is also the issue of it getting nicked if you leave it out while you're away from the van. Free standing panels also create problems with storage.

 

D.

[GJH]

I'll more or less echo what Dave said. You need to think about where you might use a panel and what for (how much power you need to generate). If possible, talk to friends who have experience of similar usage.

 

In our case we decided a panel would be useful for when we are at re-enactment events because they will probably form the vast majority of occasions when we cannot be on hook-up.

 

We plumped for a 50 watt free-standing panel (bought at the NEC show last back end) because:

1) We wouldn't have to go to the trouble and expense of having it fitted to the van, so significantly cheaper.

2) Moving it to face the sun in the circumstances in which we intended using it won't be a problem.

3) Whilst we have it fastened to the van with a bike cable when it is in use, security isn't such an issue as we will normally be on a secure site.

4) We had worked out that it would be powerful enough for our needs.

5) With just two of us in the van transporting it on trips isn't a problem and we have plenty of space to store it at home.

 

Having bought the panel so recently we've only used it three times so far but it seems to be working out fine - even in the rain and hailstones of Liverpool at the end of May :-)

 

Graham

[Don Madge]

Hi John,

 

I've got a 60 watt panel fixed on the roof of the van, on a good day I can get 3.4 amps and that's about it.

 

On a dull day it might give 0.1 or 0.2 . I don't believe some of the stories going about ref the output of solar panels. Solar panel output is like the MPG both grossly exaggerated at times or there very poor mathematicians.

 

I've had mine 10 years and it keeps my two Elecsol 100 ah leisure and the engine batteries topped up. The engine and leisure batteries are connected with a Van Bitz Battery Master http://tinyurl.com/38qejc

 

The only downside with the Elecsol batteries is that they need checking regularly. I check them about every six weeks and they usually need topping up every other check.

 

We don't have a TV, we have a 150 watt inverter for charging camera, phone and razor batteries. We also run the laptop for a few hours each evening.

 

In the winter when we are on our travels we are often with out hook up at times and even with the long dark evenings have never had a problem.

 

With our previous van a Laika 400i we had the panel free standing as I had plenty of room to store it and I would not have been able to get on to the roof to clean it.

 

When we left the van during the day we would leave the panel in the windscreen, it worked OK in places like Morocco & Turkey.

 

Many people when fitting solar panels don't take into account the need to get on to the roof to clean them also roof lights/vents casting a shadow on them.

 

We have relied on solar power now for ten years, it suits our modest needs. If you watch TV all day you have two options, larger panels or stay at home.

 

Don

 

[enodreven]

Hi,

 

I seem to remember on one of the websites (possibly MHF) that someone did a writeup on the pros and cons of Solar Panels, I think the person who wrote it may have worked for the people who run the light-houses. If anyone knows what I am talking about and the write-up is still available perhaps they could provide a link to it, as it was very helpful and explained in detail the pros and cons so i would think it may answer a lot of your questions.

 

hope this helps

[Don Madge]

I've got a copy of a write up which Mel. E had published in MMM in 2003. It's a very good article it's in Adobe Acrobat doc so I can't post it here.

 

I'mail a copy to John Keats.

 

Don

[John Keats]

Thanks to all. The next step is find someone actually using a panel with the ideas I have.

[enodreven]

Hi,

 

Hear is the link to the write-up I was talking about, I am sure it will help as it covers nearly every aspect of Solar

 

http://www.motorhomefacts.com/modules.php?name=SolarCalc

 

 

 

John Keats - 2007-06-11 11:11 AM

 

Thanks to all. The next step is find someone actually using a panel with the ideas I have.

[njw]

my panel is a 115 watt fixed on the roof and on a good day highest i have seen it was 6.2.as for having a loose panel,some poor man had his pinched at the stratford show and his was chained up and they still had it

[Frankkia]

We have 2 x 120w panels, which we have used for many years, and have moved them from 'van to 'van (I made some brackets that hold 'em to the roof rack). So far they have more than paid for their keep.

 

No it's not just the couple of quid a night that the sites charge for hook up but the whole cost of the pitch. We have free camped all round europe using the stelplatze in Germany and Aires in France and last winter in Portugal did not spend even one night on a camp site.

 

Even in the UK we now use small farm sites, usually with no hook up available. We prefer 'em any way to the big ones and at £5 instead of £17 per night the solars are saving us quite bit.

 

Another benefit is we can stay for longer without having to start a geny and so we don't have to upset the neighbours to be able to watch a bit of telly or have lights on to read by.

 

And just to be right up to date the solars are reducing our "carbon footprint" or at least off setting some of the carbon used by our deisel engine.

 

When it comes to deciding how much solar power you will need - only you can decide. It will depend on how much telly you watch, how late you stay up with lights on and what sort of camping you do. In the middle of summer you may be happy with the power from a 75w panel but in winter (even in Spain / Portugal) the sun is much lower and the daylight hours are much shorter so you would need 3 or 4 times the size of panel.

[crinklystarfish]

I have tried hard to justify solar power to myself because I believe in sustainable energy sources. However, unless you genuinely park up for long periods in the same place I really don’t see how the cost and extra hassle can be justified. Are there really that many MH users who stay in the same rough camp or farmer’s field for more than 3 or 4 days? I grant there will be some, and in these cases go nuts with your panels! I both support and salute you.

 

For the majority, and I include myself, moving on every few days, coupled with a decent battery bank of a couple of hundred ah, gives all the autonomy needed.

 

One of the main drawbacks with solar is that the very times that you are likely to draw from your reserves (when it’s cold and wet) are the times that your solar panel will be producing almost no power, paradoxically, when the days are long and bright, you are unlikely to rely upon your batteries so much. The harsh truth is that they are a feel-good accessory, but for most MH users can’t be justified in any pragmatic way.

 

When I lived on my narrowboat I had both solar panels and a wind generator. I used to moor in the middle of nowhere for a couple of weeks and didn’t need to run the engine. If your motorhome requirements mirror this kind of autonomy then buy the biggest / most efficient solar panels you can, if they don’t, buy an extra leisure battery, use energy-efficient lights and audio/video entertainment, and be glad you didn’t waste a huge wad of money.

 

[Brian Kirby]

If you go to hotter countries, the best way to a cooler van (aircon excepted) is to park in shade under trees.  Don't expect too much from any number of solar panels under these circumstances!

[Frankkia]

I agree that if you move on every couple of days buying solar is probably a waste of money as you will charge your batteries whilst on the move and can expect to last a few days without any need for additional charging.

 

We have been there and done that and now tend to stay longer and for example whilst in Portugal last winter spent 5 weeks in one place without hook up. Being winter the days were short and the temperatures not hot enough to make us search for shade. We also spent 10 or 11 days on other areas. We also do the same in the summer whilst in Germany.

 

Solars are not the way forward for everyone and before making the purchase take a hard look at your own needs.

 

Remember also that if you do go for solar power you have to have somewhere to put all that energy so you may need extra battery capacity. For our 2 x 120w we have over 300 amps of battery storage.

[chris]

We have had our panel nearly a fortnight now but we love it. Whilst it is parked up on our drive the van no longer needs to be connected to electric to top it up. This is saving on our household bill straight away and for those who have to store their van away from home it can keep the batteries topped up for you. On electric our battery would only charge up to a maximum of 12.8 but it goes to 13.8 with the solar panel. (Don't ask me why because I don't know). We have 2x 120 batteries with an 85 watt panel.

 

We like camping in CS, MCC meets, sites for holidays etc and aires and France Passion abroad so it really suits us. We do do not want to worry about putting the tv on and not being able to replenish lost voltage. We had a good digital regulator fitted and I love peaking at it to see how many amps are being produced by the sun and how much is going into the battery.etc.

 

It gives you freedom. It is not cheap but we didn't want to carry a portable panel again as we broke the last one and lifting it in and out from under the bed is a pain. Can't afford a solar panel for the house so spoilt ourselves by having one fitted to the van instead.

 

For us, it suits, but we are aware that we may require electric for winter stays depending on our energy use. I spent ages researching this site and past MMM articles on this topic and now very pleased with results.

Chris

[Clive]

You will need to justify the purchase of a solar panel using the same arguement you used to justify the van. Economically it makes far more sence to have bigger batteries so you can last your longest stay without hookup.

BUT

We would not be without our 80 watt BP panel. With an older van (10) which uses less 12 volt power than some modern vans it is quite capable of keeping up with our power requirements during the summer months.

Frequently at shows it has made up for last nights 12 volt usage by about 11.oo am.

 

Gluing it fixed to the roof is the safest and cheapest fitting compromise.

 

 

[Mel E]

The answer to the basic question is a clear 'NO!'. You cannot cost-justify solar panels. However, they are useful - even essential - if:

 

- you have high electricity usage (lots of TV, an electric compressor fridge, are two good examples)

 

- you want to camp in places that have no hookup for extended periods.

 

As Clive says, first fit enough leisure battery capacity. And don't expect short drives between camp sites to recharge them. With 2 x 120 amp hour batteries (what we've got), you'll need several hours of driving to fully charge them.

 

Mel E

====

[crinklystarfish]

I think a good way to view them is:

Lots of people have them

Many more want them

Few people need them

Have them if you desire, but know which camp you are in.

I would dare to suggest that for most users much of the power produced by panels ends up being disipated as heat energy. They certainly have their place for long term rough campers / non-EHU users, but I don't buy into the justification for keeping batteries topped up on the drive.

Curiously, most 'vans with them fitted also have many other whistles and bells and very often have the tell-tale orange umbilical cable trailing off to the nearest hook-up.

Just an observation!

[colin]

I have used a solar panel for around 7 years, it has done exactly what I want from it, I have very little room for more batteries and run a 12v fridge.

I seldom visit sites where a hook up is availible, contary to popular belief solar panels produce energy with seamingly not a lot of availible light, this is great if like me your main power drain is a fridge, cold and dark not so much power drain, Hot and sunny produces enough for fridge.

I don't park up van over winter, but if I did it would easily keep batteries topped up.

If you run gas fridge, have room for extra batteries and visit sites with hook ups, then it would be hard to justify.