YellowVanWoman Posted January 22, 2013 Share Posted January 22, 2013 Just joined, so my first thread - I'm about to buy a solar panel to put on the roof of my converted Vauxhall Movano LWB, but I'm not sure of the size. I just want it to power the lights and water pump when I spend 5 or 6 days on a French aire with no hook up. I'm thinking of a 50W panel? Any suggestions please? Link to comment Share on other sites More sharing options...
lennyhb Posted January 23, 2013 Share Posted January 23, 2013 Welcome. For 5/6 days use I would fit at least an 80 watt panel or larger. A 50 watt would probably only be enough in June/July. The output of solar panels falls off rapidly a few hours either side of midday, also from October through to April with the sun lower in the sky you never achieve the max output. Link to comment Share on other sites More sharing options...
rolandrat Posted January 23, 2013 Share Posted January 23, 2013 At the Manchester show I saw that Swift are fitting 20w solar panels to some of their caravans as standard. Link to comment Share on other sites More sharing options...
colin Posted January 23, 2013 Share Posted January 23, 2013 My intial thoughts are a 50w panel will be fine, but couple of things to consider. What type of lighting and how much are you going to use? If its LED or flouresent then no problem, if it halogen and you like to have lots of lights on then you will struggle outside of summmer. What other electrical items might you add? Things such as tv and satellite might not appeal at moment but if you extend your use into dark nights you may wish to fit them and once again 50w will struggle.Also blown air heating will add to your power requirements. On our last van a T25 we had a 30w panel which was fine, but on our present van we have assumed a higher usage and gone for 85w panel. Link to comment Share on other sites More sharing options...
Rayjsj Posted January 23, 2013 Share Posted January 23, 2013 Autotrail are fitting a 100w panel as standard on the Frontier range, they fitted an 85 watt upto this year, It's an option on the other ranges. Ray I wouldn't think a 20w was much use ? Link to comment Share on other sites More sharing options...
Tracker Posted January 23, 2013 Share Posted January 23, 2013 Hi Jean and welcome to the madhouse! If you are only using water pump and a few lights in warmer weather with long daylight you might get away with just an extra leisure battery and this would be far and away the lower cost option? Once you start using heating - especially if you have diesel fueled interior heating Eberspacher or Webasto?) and then tv and maybe computer via 12 volts it starts to get a bit more serious but even then two batteries would probably last you the better part of a week in mild weather without running the engine? Perceived wisdom is to go for the biggest solar panel that you can afford / justify / have roof space for and fit a split charge regulator to keep both leisure and engine battery topped up. This is particularly useful to prevent the whole lot going flat when the van is maybe not in use for a week or three. Hope that helps and please come back with any other questions as an expert is bound to be along soon!! Link to comment Share on other sites More sharing options...
spospe Posted January 23, 2013 Share Posted January 23, 2013 YellowVanWoman - 2013-01-22 11:56 PM Just joined, so my first thread - I'm about to buy a solar panel to put on the roof of my converted Vauxhall Movano LWB, but I'm not sure of the size. I just want it to power the lights and water pump when I spend 5 or 6 days on a French aire with no hook up. I'm thinking of a 50W panel? Any suggestions please? The size you need depends on your useage and without some reliable data any advice is something of a guess. I echo others and would say that anything under 85 watts (max output) will not be much use. Remember that in practice, the effective output will be circa a half of the maximun and you can forget the two hours after sunrise and before sunset. You must have full sun on the panel (no shade at all) for maximum output. The drop without sun on the panel is as much as 90% (blue sky, but no sun on the panel = about 400 m/a from an 85 watt panel, as against 4.25 amps with full sun). Link to comment Share on other sites More sharing options...
YellowVanWoman Posted January 23, 2013 Author Share Posted January 23, 2013 Wow, so many replies so soon! Thanks everyone for your help. I'll take Tracker's advice and go for the highest Wattage one I can afford. Never going to have a TV, don't have built in heating. Might look into the advice on just buying an extra battery - much less cost and hassle, didn't think of that. Thanks again, all. :-) Link to comment Share on other sites More sharing options...
lennyhb Posted January 23, 2013 Share Posted January 23, 2013 With no heating or a TV a 2nd leisure batty should cope. It's always advisable to fit a second battery before going to the expense of a solar panel. Link to comment Share on other sites More sharing options...
maggyd Posted January 23, 2013 Share Posted January 23, 2013 lennyhb - 2013-01-23 1:49 PM With no heating or a TV a 2nd leisure batty should cope. It's always advisable to fit a second battery before going to the expense of a solar panel. But I would run your fridge off gas if you have the option, we always did that anyway even with solar panel. Link to comment Share on other sites More sharing options...
Tracker Posted January 23, 2013 Share Posted January 23, 2013 maggyd - 2013-01-23 6:24 PM lennyhb - 2013-01-23 1:49 PM With no heating or a TV a 2nd leisure batty should cope. It's always advisable to fit a second battery before going to the expense of a solar panel. But I would run your fridge off gas if you have the option, we always did that anyway even with solar panel. Can I just clarify that (unless someone has tampered with the wiring) a motorhome fridge will ONLY ever run on 12 volts whilst the engine is running. This is because it takes round about 8 amps continuous to run it which is unsustainable for all normal single or twin battery setups regardless of how much solar power you might be generating in the daylight hours. Link to comment Share on other sites More sharing options...
Cliffy Posted January 23, 2013 Share Posted January 23, 2013 IMHO I would fit the largest you can physically get on your roof.as you will always want more power than you have at sometime or other no matter what size you fit. I don't know if it is practical but I often think it would be good, when parked for a few days, to have the ability to tilt the panel up so it is facing the sun to get the best out of it. We have an 80w panel with two 110 amp leisure batteries and in France in spring and Autumn we can keep going without hook up indefinitely but in the UK after 3 days the batteries gradularly run down but we do have a TV with Sat reciever, laptrop, extractor fan over the cooker on top of the lights and water pump. Once a week or so the co-pilot uses heated rollers which we run off out invertor. Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 23, 2013 Share Posted January 23, 2013 Also, bear in mind that if you fit the additional battery (ideally it should be virtually the same age as the existing battery (within six months), of similar size (capacity), and of the same type (chemistry)) without the solar panel, you will be reliant on the engine alternator to re-charge the batteries between stops. Remember, that whereas the larger the capacity you install the longer you can last, that additional capacity also takes longer to re-charge. You may find you need to drive for several hours between aires to replenish the charge or, the next time you stop, you will still have part depleted batteries, which may fail soon thereafter. Bear in mind also that you should not, ideally, take significantly more than 50% (depending on battery type, possibly up to 60%) of its capacity from the battery, or you risk shortening its life. IMO, if your pattern of use is to spend several days at at time on a particular aire, and then move only a relatively short distance to another, where you will also expect to stay for several days, and so on, I think you would probably be better off with a larger solar panel to keep the existing battery continually topped up while not moving, than installing additional battery capacity and relying on the drive between aires to top up the battery. But, as with much to do with motorhomes, it is a balance that has to be guided by preference and how you use your 'van. But, if you alternate aires with sites, and then use EHU to re-charge, the additional battery would seem to offer the better solution. Link to comment Share on other sites More sharing options...
YellowVanWoman Posted January 23, 2013 Author Share Posted January 23, 2013 Thanks to everyone again for your advice - so much to think about!! Looks like I'll be settling for the largest solar panel I can fit/afford as we do spend a lot of time away from hook up, on French aires and also on the France Passion vineyards. Photonic Universe seem reasonably priced so far on the net. Link to comment Share on other sites More sharing options...
Paul- Posted January 24, 2013 Share Posted January 24, 2013 I've just seen a add on a caravan forum offering 80 wtt panels, I've cut and pasted their price below Price supplied & fitted - £300 inc. VAT (also Supply Only for £200 inc VAT) Price for 2x 80W panels supplied & fitted - £475 inc. VAT Link to comment Share on other sites More sharing options...
lennyhb Posted January 24, 2013 Share Posted January 24, 2013 You can buy 80Watt panels for £75 now days. Link to comment Share on other sites More sharing options...
spospe Posted January 24, 2013 Share Posted January 24, 2013 Tracker - 2013-01-23 6:42 PM maggyd - 2013-01-23 6:24 PM lennyhb - 2013-01-23 1:49 PM With no heating or a TV a 2nd leisure batty should cope. It's always advisable to fit a second battery before going to the expense of a solar panel. But I would run your fridge off gas if you have the option, we always did that anyway even with solar panel. Can I just clarify that (unless someone has tampered with the wiring) a motorhome fridge will ONLY ever run on 12 volts whilst the engine is running. This is because it takes round about 8 amps continuous to run it which is unsustainable for all normal single or twin battery setups regardless of how much solar power you might be generating in the daylight hours. Tracker is correct for absorbtion fridges, but compressor fridges take power as and when needed, governed by their thermostats and can last for several days on dual 110 a/h batteries. However, you would need a big panel system of, say 2 x 135 watt, in order to sustain a fridge of whatever type. After 6 years use and keeping records, for our use, the panel has been a poor investment, bigger batteries would have been better / cheaper. Link to comment Share on other sites More sharing options...
Tracker Posted January 24, 2013 Share Posted January 24, 2013 spospe - 2013-01-24 3:42 PM After 6 years use and keeping records, for our use, the panel has been a poor investment, bigger batteries would have been better / cheaper. I am inclined to agree. However the one really big advantage for us of solar pv with a split charge regulator is that no matter how long you leave the van the batteries, both starter and leisure, don't go flat which not only helps helps them to survive longer it also makes for a more relaxed approach because you know that if you do go away without the beastie for two weeks the van will start when you come back! But then again you could always leave it on mains hookup as long as all batteries can be simultaneously kept charged, although I'm not sure if the van's built in charger is suitable for long term constant running? Link to comment Share on other sites More sharing options...
YellowVanWoman Posted January 24, 2013 Author Share Posted January 24, 2013 Nor am I Tracker, it's all getting too technical for me, split chargers? I'll have to look it up! Link to comment Share on other sites More sharing options...
Paul- Posted January 25, 2013 Share Posted January 25, 2013 lennyhb - 2013-01-24 10:32 AM You can buy 80Watt panels for £75 now days. You can buy caravans & motorhomes for that sort of money too (lol) I think a lot of the problems people have with solar is that they look at the price of solar panels and controllers, especially the important part of the system the controller, they should really be looking at the efficacy and the electronics. Would they buy a sandwich by price and ignore the contents (?) Link to comment Share on other sites More sharing options...
Tracker Posted January 25, 2013 Share Posted January 25, 2013 YellowVanWoman - 2013-01-24 10:58 PM Nor am I Tracker, it's all getting too technical for me, split chargers? I'll have to look it up! Sorry Jean - let me endeavour to clarify, not that I am an expert. Normally a solar panel is wired up to just the leisure battery(ies) via a regulator which prevents the batteries from being over charged when they are fully charged because this could potentially damage the battery(ies) by 'boiling' the electrolyte (acid) dry. Some solar regulators allow you to take a second pair of cables to the starter battery to ensure this is kept topped up too or you can add a special box of electronics to do this and this is called split charging. I use one of these - http://www.sterling-power.com/products-chargers-maintainer.htm It distributes the solar charge to all batteries in much the same way that the engine alternator (the bit on the engine that generates the 12 volt electricity that both the van and the habitation side use) is allowed to not only charge the engine battery but the internal leisure battery too (this is fitted by the converter so not something to worry about). The purists and experts will of course tell us that it is not quite that simple! Hope this helps but if not - ask us another Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted January 25, 2013 Share Posted January 25, 2013 Paul- - 2013-01-25 10:00 AM lennyhb - 2013-01-24 10:32 AM You can buy 80Watt panels for £75 now days. You can buy caravans & motorhomes for that sort of money too (lol) I think a lot of the problems people have with solar is that they look at the price of solar panels and controllers, especially the important part of the system the controller, they should really be looking at the efficacy and the electronics. Would they buy a sandwich by price and ignore the contents (?) In a similar vein,how long does you average solar panel "last"...? Do owners consider them a "fit'n'forget" item..or something more along the lines of leisure batteries(..which need replacing and/or fail)? :-S Link to comment Share on other sites More sharing options...
Tracker Posted January 25, 2013 Share Posted January 25, 2013 pepe63 - 2013-01-25 10:38 AM In a similar vein,how long does you average solar panel "last"...? Do owners consider them a "fit'n'forget" item..or something more along the lines of leisure batteries(..which need replacing and/or fail)? :-S I have been using the same 50 watt panel and regulator for over 4 years on two vans and it still does what it says on the label. I know people who have had panels a lot longer than that without problem so I guess they are pretty reliable in the main - although there will always be exceptions and failures. Link to comment Share on other sites More sharing options...
colin Posted January 25, 2013 Share Posted January 25, 2013 pepe63 - 2013-01-25 10:38 AM In a similar vein,how long does you average solar panel "last"...? Do owners consider them a "fit'n'forget" item..or something more along the lines of leisure batteries(..which need replacing and/or fail)? :-S Recently sold our T25 van, the solar panel was AFAIK still going strong after over 13years of use. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted January 25, 2013 Share Posted January 25, 2013 Well,you certainly couldn't complain with getting 13 years out of it,could you..... ;-) Link to comment Share on other sites More sharing options...
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