Mike B. Posted August 22, 2011 Share Posted August 22, 2011 Hi I wonder if someone can give me some detailed help- After conflicting information from various solar panel sales people all I want to know is- How big a panel do I need just to keep my leisure battery topped up when I am wild camping for say 2/3 days and running TV, Sky box, lights (LED) and general things like taps & loo flush without flattening the battery in between charges? I would run the fridge on gas not battery Can anyone give me an idea? Also are they hard to fit and is it ok DIY or should I leave it to the professionals to fit with regulators etc? Thanks for any info Mike Link to comment Share on other sites More sharing options...
747 Posted August 22, 2011 Share Posted August 22, 2011 An 80 watt panel should easily be big enough, even in Winter. You should just about last out for 2/3 days without one, so I would look at the state of your battery and double up if you only have one. It is no good having a large solar setup and one small, old and possibly feeble battery. When wildcamping, you need alternatives. I have 2 x 110 Ah batteries and a 90 watt panel. If we have had a run of bad weather (not unheard of in the UK), I nurse the power a bit. Instead of using the 15.6" TV and Sky digibox, I switch to the 10" TV with built in Freeview. This drops my power consumption from around 6 amps to 1.5 amps. I should stress that I wildcamp most of the time and can last almost indefinitely in an average UK Summer. I have only had to economise on the odd occasion and it is usually in Winter. If you use the van all year round off hookup, get a bigger panel as they lose effectiveness (and output) when the sun is low. Mine is freestanding, not fixed to the roof. In Winter, I get double the output of a flat, fixed panel. I hope that helps. Link to comment Share on other sites More sharing options...
Mike B. Posted August 22, 2011 Author Share Posted August 22, 2011 747 - 2011-08-22 7:39 PM An 80 watt panel should easily be big enough, even in Winter. You should just about last out for 2/3 days without one, so I would look at the state of your battery and double up if you only have one. It is no good having a large solar setup and one small, old and possibly feeble battery. When wildcamping, you need alternatives. I have 2 x 110 Ah batteries and a 90 watt panel. If we have had a run of bad weather (not unheard of in the UK), I nurse the power a bit. Instead of using the 15.6" TV and Sky digibox, I switch to the 10" TV with built in Freeview. This drops my power consumption from around 6 amps to 1.5 amps. I should stress that I wildcamp most of the time and can last almost indefinitely in an average UK Summer. I have only had to economise on the odd occasion and it is usually in Winter. If you use the van all year round off hookup, get a bigger panel as they lose effectiveness (and output) when the sun is low. Mine is freestanding, not fixed to the roof. In Winter, I get double the output of a flat, fixed panel. I hope that helps. Thanks for the info At present it will last about 2 days and then the inverter starts beeping when mrs turns taps on whilst watching tv at night. As far as I am aware battery is ok but just wanted to keep it topping up during the day with the sunlight to replace what I use night before, so as not to drop below say 3 quarters on the display. You reckon an 80 watt panel should do this? Why do you get double the output in Winter? is this due to sun/angle or am I missing something? Link to comment Share on other sites More sharing options...
lennyhb Posted August 22, 2011 Share Posted August 22, 2011 I fitted an 80 watt panel to the roof earlier in the year, easy to fit,. hardest part is running the cables through the van. We have 2 x 80 A/H gel batteries, 2 weeks in Scotland in April came back each evening to fully charged battery, our lights are LED, have an Oyster 85 dish with a 17" Camos TV + sound system with sub woofer. I have been running tests and found only get max output from around 11:00 to 15:00 panel is rated at 4.66 amps max last month on a clear day I was getting 4.8 - 5.2 amps that's after any drop in the cables not bad for a cheap ebay panel, by 4:30pm down to about 2 amps, slightest cloud or shadow output falls of by 25%- 50%. When I fitted it in January got a max of 2.5 amps for a couple of hours around midday only 1 amp for a few hours either side. In the summer I reckon we have enough charge for indefinite use, winter will probably give us 2-3 more days if we have clear sky's. If you want to use the TV a lot in winter I would ditch the inverter and get a 12v LED backlit TV some take as little as 2.5 amps for a 19". Link to comment Share on other sites More sharing options...
747 Posted August 22, 2011 Share Posted August 22, 2011 Hi Mike, I wildcamp all year round and need to get the max. out of my panel. For the last 6 months, I have had a Digital Ammeter linked into the system to give me info on the best way to set up the panel. I can get around 6 amps at best in the summer by angling the panel. Early in the day, I set it up at about 45 degrees and after about 11 am, set it to an angle of 10 to 15 degrees (from the horizontal). Back to 45 later in the day. If the panel were to be laid flat in Summer, the drop in output is not so great at the height of the sun but it is more so in the morning and evening and overall, there is quite a bit of difference. This is not so important as we all tend to use less power anyway at that time of year. In Winter, I tend to have a steeper angle at various times of the day as the sun is much lower. Last February, I could get 4 amps quite early in the day when it was less than 2 amps if laid flat. The difference in output was a lot at all times of a Winters day, compared to a fixed installation. With the need for heating and longer nights, the drain on batteries is much more than Summer (and the lure of sitting in front of a TV). A bit off topic but this year has been quite a windy one and I also have a wind turbine (rated at 80 watts but that claim is a joke) which I have used as well. I can have the panel and the turbine working at the same time to give a bit more power. Forget having a wind turbine, they are little more than a trickle charger unless it is a full blown gale. Luckily I have plenty of payload and storage space so I just leave it in the van for emergencies. Link to comment Share on other sites More sharing options...
lennyhb Posted August 23, 2011 Share Posted August 23, 2011 747 - 2011-08-22 11:04 PM I can get around 6 amps at best in the summer by angling the panel. Early in the day, I set it up at about 45 degrees and after about 11 am, set it to an angle of 10 to 15 degrees (from the horizontal). Back to 45 later in the day. If the panel were to be laid flat in Summer, the drop in output is not so great at the height of the sun but it is more so in the morning and evening and overall, there is quite a bit of difference. This is not so important as we all tend to use less power anyway at that time of year. I agree Jim what you do makes it much more efficient but it's just not practical (for us anyway). We get up have breakfast go out for the day coming back at 6 or 7pm, wouldn't be able go out or do anything if I had to be around to keep moving the panel. Link to comment Share on other sites More sharing options...
ips Posted August 23, 2011 Share Posted August 23, 2011 Why not just fit an extra battery, we can last 5 days with ours running lights water pump blown air fans etc, (no tv as we dont have one) Link to comment Share on other sites More sharing options...
sshortcircuit Posted August 23, 2011 Share Posted August 23, 2011 Very interesting post. Now considering an 80w panel but undecided which. eBay has mono and poly chrystaline, what's the difference? I also note panels at £150 and what appears the same at £500, again what's the difference? Link to comment Share on other sites More sharing options...
lennyhb Posted August 23, 2011 Share Posted August 23, 2011 Mono are more efficient, our £160 one from ebay appears to perform as well as any other panel I've seen in use. Some people reckon the cheap ones are 5% less efficient than expensive ones, ours in bright sunlight gives more than it's rated output. Worth investing in a good PWM type charge control rather than the cheap £20 ones often bundled with the panels. Link to comment Share on other sites More sharing options...
Mike B. Posted August 23, 2011 Author Share Posted August 23, 2011 Hi Again Everybody Thanks ever so much for all the very detailed information-it has been very helpful for me. I have (and am) trying to digest it all-I think I will go ahead with a roof one but am a little apprehensive about fitting it myself and blowing up the electrics! Does anybody who has fitted one know if they come with instructions or do you have to have a degree in electronics?? Mike Link to comment Share on other sites More sharing options...
lennyhb Posted August 23, 2011 Share Posted August 23, 2011 The charge controllers come with instructions and there is plenty of info on the web. The hardest bit is routing the cables. I use thin wall auto cable it a bit stiff but a much smaller diameter cable for the relative current carrying capacity (thin wall high temperature insulation, higher purity copper) I took mine into the van via the satellite cable grommet, took a couple of hours to get the fitting off the roof & clean it out (full of stikaflex ) and then about half a day getting the cables under the raised floor in the van (with wife's help & threading rods). I brought the Schaudt charge controller as it plugs straight into my Elektroblock charger & charges leisure & engine batteries. With my particular Elektroblock if you don't use the correct charge controller it won't charge the batteries from the mains, not that is much of a problem as I've never needed to hook up since fitting the panel. Just do a bit of research before going ahead plenty of info out there. Link to comment Share on other sites More sharing options...
Mike B. Posted August 23, 2011 Author Share Posted August 23, 2011 lennyhb - 2011-08-23 11:06 AM The charge controllers come with instructions and there is plenty of info on the web. The hardest bit is routing the cables. I use thin wall auto cable it a bit stiff but a much smaller diameter cable for the relative current carrying capacity (thin wall high temperature insulation, higher purity copper) I took mine into the van via the satellite cable grommet, took a couple of hours to get the fitting off the roof & clean it out (full of stikaflex ) and then about half a day getting the cables under the raised floor in the van (with wife's help & threading rods). I brought the Schaudt charge controller as it plugs straight into my Elektroblock charger & charges leisure & engine batteries. With my particular Elektroblock if you don't use the correct charge controller it won't charge the batteries from the mains, not that is much of a problem as I've never needed to hook up since fitting the panel. Just do a bit of research before going ahead plenty of info out there. Thanks Lenny You have made my mind up for me. That frightens me! I can see all sorts of problems I would create by doing it myself! I would probably blow up the electrics and flood the van or at least create a water inlet in the roof. Thanks for your advice at least I know what to buy but think I will hire a competent person to fit it for me Mike Link to comment Share on other sites More sharing options...
lennyhb Posted August 23, 2011 Share Posted August 23, 2011 ips - 2011-08-23 9:46 AM Why not just fit an extra battery, we can last 5 days with ours running lights water pump blown air fans etc, (no tv as we dont have one) I would agree not worth going to the expense of a panel if a second battery will cope with your needs. We could last 5-6 days in the summer about 3-4 in the winter before fitting the panel. We decided to fit one after ambling around France last year and only doing a few miles between stops. Batteries started to get a bit low after a couple of weeks & had to find a hook up and most of the campsites were closed as it was September. We were watching TV a bit & DVD's a fair bit, heating on quite often evening & morning as were were often quite high up so it was a bit chilly in the evening. Link to comment Share on other sites More sharing options...
Guest Tracker Posted August 23, 2011 Share Posted August 23, 2011 Unless you have a compressor type of fridge it should only work on 12v when the engine is running as it consumes, I think, about 8 amps and would quickly flatten the leisure battery? If you have diesel heating like Eberspacher which takes a 20 amp surge to fire it up everytime I would go for twin batteries and a solar panel! It sounds as if for your situation a second battery, as already suggested, would be the easiest solution So why not try the simplest and most cost effective remedy first - a second battery? Not too expensive to buy and simple to fit? Then and only if that fails to keep you going consider the expense of a solar panel? You must also get a regulator with the solar panels or you will be bunging 20 v into the batteries and will soon ruin them. And don't forget heavy duty cable to carry the current without voltage drop en route from roof to battery! Link to comment Share on other sites More sharing options...
colin Posted August 23, 2011 Share Posted August 23, 2011 With 12+ years experiance of solar when we got new van it was a nobrainer, didn't bother with second battery just had a 85w panel fitted, expecting it to come into it's own this winter when I get around to coupling it up to engine battery, so can leave van for a few weeks and still have fully charged batteries. Link to comment Share on other sites More sharing options...
tonyishuk Posted August 24, 2011 Share Posted August 24, 2011 How often do you have to clean a flat roof solar panel, to maintain performance ? Rgds Link to comment Share on other sites More sharing options...
colin Posted August 24, 2011 Share Posted August 24, 2011 tonyishuk - 2011-08-24 7:37 PM How often do you have to clean a flat roof solar panel, to maintain performance ? Rgds Thats a good question, our last panel was 'semi rigid' so had no frame, and seemed to keep reasonably clean, so say once a year? The 'new' panel is framed, this may lead to build up of dirt, I've yet to find out. Link to comment Share on other sites More sharing options...
bobalobs Posted August 24, 2011 Share Posted August 24, 2011 Depends what you park under and how many seagulls are about!! In normal circumstances I wipe it down at the same time that we clean the Heki. We have a 90watt solar panel and two 110 amp batteries with Webasto diesel heating and do not need a hookup for at least six months a year . We do not use an inverter and the little television we watch is on 12 volt. If you can avoid an inverter this helps. Link to comment Share on other sites More sharing options...
lennyhb Posted August 24, 2011 Share Posted August 24, 2011 Mine's been on since January only washed it once when cleaning the van roof. Regularly have a look at it from a bedroom window usually check it before going away it stays remarkably clean. Appears to do a much better job of self cleaning in heavy rain showers than the van roof. Link to comment Share on other sites More sharing options...
Mike B. Posted August 26, 2011 Author Share Posted August 26, 2011 colin - 2011-08-23 9:07 PM With 12+ years experiance of solar when we got new van it was a nobrainer, didn't bother with second battery just had a 85w panel fitted, expecting it to come into it's own this winter when I get around to coupling it up to engine battery, so can leave van for a few weeks and still have fully charged batteries. This is the route I am almost certain to take-on considering everybody's opinions it appears to suit me best. Thanks once again all for the info Mike Link to comment Share on other sites More sharing options...
spartan3956 Posted August 26, 2011 Share Posted August 26, 2011 I have just fitted a 120 watt solar panel with a 10 amp controller this is connected to 2x 105 amp batteries. I also run sky with a 22" TV all the lights pumps and even a 400 watt vacum cleaner.all run off a 1600 watt inverter. Next day around midday the batteries are 100% .( summer) Took me around 5 hours to fit as they say routing the cables is a bit of a pain but well worth done properly i used a heavy duty extension lead for the cable 20 amps. The controller comes with instructions and besides the panel and controller, a waterproof gland for the roof, mastic or silicon to seal it and solar panel connectors. Total cost £330 wish i had done it years ago. I would suggest the biggest panel you can fit above 120 watt and you have to use a bigger controller I just leave the lights on when i want. no more worries. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.