parkmoy Posted September 8, 2007 Share Posted September 8, 2007 I have seen a 1.5W panel advertised. It plugs in the cigar lighter and is reputed to provide a 'service level' charge to the battery when the vehicle is laid up for long periods. Would this be any use? Link to comment Share on other sites More sharing options...
JimJam Posted September 8, 2007 Share Posted September 8, 2007 I often saw these little panels outside peoples vans and wondered how much use they really were. Anyway I bought one, not for my van but to keep the batteries on an electric fence that protects my chickens from foxes topped up. I had two batteries that I rotated and they generally lasted 5 days each in summer and about 3 days in winter if it really got cold, the fence is on 24 hours a day. I do not know the wattage but the panel isn't much bigger than a sheet of A4 paper. In the summer the time between battery changes went from five days to six and even seven. In the winter I didn't notice any real difference! But then I do live in Wales :-D Based on this most scientific study, I would say that in the summer they may well put a little juice into your battery. Link to comment Share on other sites More sharing options...
Guest Syd Posted September 8, 2007 Share Posted September 8, 2007 A complete waste of time. I have one that you can have for free. I will be glad to see the back of it Link to comment Share on other sites More sharing options...
Mel E Posted September 8, 2007 Share Posted September 8, 2007 Total waste of space. You can work it out easily enough - just remember amps = watts / volts. To charge the battery a solar panel typically operates at about 16 volts, so your panel is putting 1.5/16 amps, i.e., less than one-tenth of an amp into the battery each hour. And that's only in clear sunshine with the panel surface at right angles to the direct line to the sun. In typical winter sunshine, with the panel flat on the dashboard, you'll be lucky to get more than one-quarter of an amp-hour fed into your battery during the whole day. That's hardly maintenance level for even a smallish 85 amp hour battery (0.25 into 85 won't even keep up with the drain caused by an alarm system!). And that's only on sunny days - forget any input on cloudy winter days! Mel E ==== Link to comment Share on other sites More sharing options...
Clive Posted September 8, 2007 Share Posted September 8, 2007 Might charge your mobile phone over a few days!! Otherwise waste of space. Link to comment Share on other sites More sharing options...
Mike Parke Posted September 8, 2007 Share Posted September 8, 2007 I do not understand the technical side of amps/watts etc. but we had a solar panel on our 'old' van as the alarm was always switched on even when parked up on our driveway. The solar charger, which I stood up on the outside of the windscreen and connected direct to the base vehicle battery, managed to keep the battery charged up sufficiently to enable a instant key start every time, whereas before I installed the panel the battery was drained by the alarm in a matter of weeks if we did not use the m'home. I use it on the 'new' m'home for a trickle charge to be fed in to the battery whist parked up. Regards, Mike. Link to comment Share on other sites More sharing options...
Clive Posted September 8, 2007 Share Posted September 8, 2007 Mike, The given output of this solar panel is 1.5 watts. Thats just over 0.1 of an amp under ideal direct sun conditions in summer on the equator. In the UK a great deal less. It is unlikely to keep up with the continual current taken by the alarm system or even the batteries own internal leakage if its not brand new. Does that put things in perspective? C. Link to comment Share on other sites More sharing options...
Frankkia Posted September 9, 2007 Share Posted September 9, 2007 Clive is quite right - for car or leisure battery use they are a total waste of space. I bought one a few years ago and use it to stop the motor bike battery going flat (but that is only a 7 Ah battery and it just about copes. You would need a panel with AT LEAST 0.5 Ah (6w) output to keep a vehicle battery, which doesn't have any other drain on it, fresh. Link to comment Share on other sites More sharing options...
parkmoy Posted September 9, 2007 Author Share Posted September 9, 2007 Thanks for the replies everyone, I think I'll give it a miss! Link to comment Share on other sites More sharing options...
Champstar Posted September 9, 2007 Share Posted September 9, 2007 What do the experts think of the 13W briefcase solar panel set ups...would they be any good for occasional use or to keep the bat topped up when parked for a long period of time....am I correct in thinking that it would produce a little under 1amp..charge? Cheers all Link to comment Share on other sites More sharing options...
Guest starspirit Posted September 9, 2007 Share Posted September 9, 2007 I find it hard to understand the attraction of solar panels unless you are going to be on site in the sunshine for long periods in which case the size and cost of the setup is considerable, but with big enough panels you should be able to manage for a while without starting the engine. There again in that situation mains hook up is simpler and cheaper. For most of us twin 110ah leisure batteries will provide enough power for 3 to 4 days at a time and even if the battery gets a bit low, running the engine on tickover for 15 minutes will probably give you another few hours worth of juice and all at a fraction of the price of a decent solar system. But that's just my view of course and I would be very interested to hear why others think the solar solution is the way forward. Link to comment Share on other sites More sharing options...
martin r c Posted September 9, 2007 Share Posted September 9, 2007 Hi ,I use a 5w solar panel, it does help prolong the amount of time I can run off the battery. but it would never recharge a flat one.But it,s better than nothing. Martin Link to comment Share on other sites More sharing options...
Clive Posted September 9, 2007 Share Posted September 9, 2007 13 watt panel, about 1 amp under ideal direct sun conditions in summer on the equator. In the UK normally a great deal less. But sufficient to maintain a reasonable battery Link to comment Share on other sites More sharing options...
Guest starspirit Posted September 9, 2007 Share Posted September 9, 2007 Clive do you mean that one amp will maintain a battery whilst the van is parked up not in use as it ought to be just about enough to compensate for alarm, radio memory, natural loss and control panel loss but surely little else? I bow to your amazing and extensive technical expertise but I would have thought that one amp is hardly enough to keep things going whilst on site? Link to comment Share on other sites More sharing options...
Mike Parke Posted September 9, 2007 Share Posted September 9, 2007 Clive - 2007-09-08 11:13 PM Mike, The given output of this solar panel is 1.5 watts. Thats just over 0.1 of an amp under ideal direct sun conditions in summer on the equator. In the UK a great deal less. It is unlikely to keep up with the continual current taken by the alarm system or even the batteries own internal leakage if its not brand new. Does that put things in perspective? C. Clive, I bow to your techical knowlegde but I call it only as I find it! Maybe mine has a greater output capacity, is that possible? It measures circa 12" x 4" but I cannot recall from where it was purchased! Regards, Mike. Link to comment Share on other sites More sharing options...
colin Posted September 9, 2007 Share Posted September 9, 2007 Richard I'm sure we have been throu this before, but here goes. Solar may not be the way forward for all, but for us in a small van with little spare room for extra battery and a electric fridge, and staying at places without hook up its works a treat, also if laying up van for some weeks, link van and leisure batteries together and permanantly charged batteries, even in middle of winter. Link to comment Share on other sites More sharing options...
Guest starspirit Posted September 10, 2007 Share Posted September 10, 2007 Fine Colin - each to his own and if it works for you that is all that is important. I'm not knocking it - I just wanted to point out to those who are pondering energy solutions that there are alternatives that work well. I never use a hook up either and we have found that the double battery solution has worked well for us over many years. However I can see the benefit of a small top up solar charger to keep the batteries in trim when the van is not in use for a few weeks and I might even get one myself, although I doubt I would link engine and leisure batteries! One day we may choose the solar solutions as a major energy source as I can see the benefit, but for now at least, and for us the cost to benefit and convenience ratio still seems to favour twin batteries. Happy camping Link to comment Share on other sites More sharing options...
Mel E Posted September 12, 2007 Share Posted September 12, 2007 Starspirit, I think you've misread Clive. He doesn't say that 1 amp is enough to keep you going while on site - he's talking about maintaining the charge level of the engine battery (NOT including the leisure batteries) when parked up - that means 1 amp should be enough to overcome battery loss by alarm, etc., drain and natural wastage. How much you need when camping is totally different and depends on your usage. For example, we have a compressor fridge/freezer rather than a gas/mains/12 volt absorption fridge, so we use a lot more 12 volt power - but no gas! Mel E ==== Link to comment Share on other sites More sharing options...
Clive Posted September 12, 2007 Share Posted September 12, 2007 Yup, Mel's correct. We are able to sustain ourselves indefinately during the summer with gas and Solar panel and a 160 Ah battery. Ours panel is a BP 80 watt jobbie. But If had a compressor fridge and/or a diesel heater it would be a totally different ball game as they both eat amps like there is no tomorrow. Link to comment Share on other sites More sharing options...
Tony Norton Posted September 12, 2007 Share Posted September 12, 2007 Hello all, I think a lot of the claims made by some suppliers are slightly exaggerated to say the least. One I saw at the recent Motorhome & US RV show claimed 120Watts, however, if you multiplied the maximum current by 12V (or even the possible open circuit voltage of, say, 18 to 20V) it came to nowhere near 120W! This does not mean, though, that I think they are not "a good thing", if you go for the right type. Our own, recently self fitted, 64W "triple junction technology" device, is 3 layer and alleged to respond to light frequencies from Ultra-Violet thru to Infra-Red in 3 bands. All I can say is that we recently did a 6 day stay in Cornwall, in some pretty abysmal weather and, even at dusk on a rainy day, it was still supplying current to the battery and kept the batteries up to well above 12V. 13.9V when the sun did shine and 12.4V in the above mentioned dismal conditions. O.K. we do have a couple of decent 100AH domestic batteries, but we were using lights and TV as often as we wanted. It was not an overly expensive job, less than £450 for: - the panel, brackets and stainless-steel bolts to attach it to the roof-rack, stainless-steel deck glands to run the cables through the roof (much better than holes with a dollop of mastic), regulator and Sargent's purpose made adaptor cable. I consider it money well spent. :-) Tony Norton Link to comment Share on other sites More sharing options...
Tony Norton Posted September 12, 2007 Share Posted September 12, 2007 Update, have just been out to the van to check levels. It's been a bright day but at 18:00hrs with 90% cloud cover the voltage was 13.9V with a current to the battery of 0.6A. 'Nuff said I think. Tony N Link to comment Share on other sites More sharing options...
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