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Solar Panels For Winter


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Help or advice would be appreciated. We keep our van in a secure store some way from home. We are really obligated to keep the leisure battery in the van during the winter to power the alarm and tracker drawing about 30-35 mamps. This will drain the battery if we don't use the van for sometime which will shorten the life of the battery and jeopardise the alarm and tracker. We have been quoted £400 to install a panel and controls but when you compare the cost of a new battery and the discount on our insurance gained from the tracker and alarm that sort of expenditure doesn't make sense.

 

I favour a temporary arrangement to see us through the winter period. One contributor has spoken of setting up a panel immediately beneath the rooflight but I am not sure how effective that is. Another refers to a briefcase unit propped inside the front windows.

 

If there is anybody who has been through this and can offer advice it would be appreciated.

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Hi - if all you need to do is top up the tiny draw from the alarm and tracker, get a wee 10w panel and put it in the window, or roof light. Why spend a load of cash on something that is a huge sledge hammer to crack a tiny nut ? unless of course going forward you are going to visit sites that has no EHU ?

 

we have 100w panel on the roof, but we do visit sites with no EHU.

 

also think - if we get lots of snow, and you have a roof mounted panel - it will only get covered, and be no good at all

 

food for thought . ....

Power unit at front all the time, Van behind (hopefully) some of the time unless I'm reversing then it's all the other way round . .... Or is it?

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We have a 13w suitcase type solar panel (Maplin) that we keep in the bedroom heki recess when the van is in storage. We rest the top of the case on the plastic lugs of the recess and use a cut down adjustable shower pole at the lower end to make sure that it doesn't slip. We have had this for over two years now and never had a problem keeping the battery topped up to around the 12. 8 mark in the winter. We also have a tracker and alarm fitted.

 

Don't regret the outlay for the panel as before we had it we lost one battery and don't want that to happen again. It is also handy if we go off EHU.

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Maplins are doing a simple solar charger at the minute, £9. 99, output should be enough for your purposes.

Nissan X-Trail Tekna + Coachman Festival 450

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I have a 10watt panel in the rooflight and it works a treat

The more I learn the more I know,the more I know the more I forget,the more I forget the less I know :blink:

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Our 40w suitcase unit in the front window doesn't seem to working very well - but we do face north and the weather's not been particularly bright of late. In fact we've just come back from the storage site about an hour ago and our battery is reading 12. 2v on the van control panel and 50% on the solar unit's charge controller. The van's been there just over a month. Maybe we should look at trying to site it high up in the Heki, but we'll probably be using the van in the new year, so it should be ok.

2019 Ford Kuga 2. 0 (150 bhp) AWD Manual and 2022 Coachman Acadia GTS 565.

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If the battery is reading 12. 2 volts it is in desperate need of recharging or will be ruined.

 

I must admit I cant understand how some people claim to get away with so small Wattage panels in winter, and then use them inside windows, the numbers dont add up for me.

 

I help someone recently where his van is in a barn; here he used a fixed 90 Watt panel outside the barn. That works with the winter we have had sofar. I think it is oversized but not by a huge amount, I thought 40Watts would be okay but at the price of cells today he opted to make sure rather than risk battery damage and loss of alarm security.

Edited by JTQ
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Up to three inches of snow on a solar panel may have no real adverse effect.

 

This info was printed in the instruction manual with an Exide solar panel I owned. :)

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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I have heard that some of the medium power solar panels (30-50 watts) that have in-built controllers struggle to power up the controller in winter. The beauty of a 10 watt panel is that there is no need for a controller so it is pure current into the battery. The maximum current a 10 watt panel can provide in summer is around 800 m/a and in winter this can drop to 100 m/a or less but should keep the battery topped up and provide power for the alarm and tracker. What effect the window or rooflight would have on power I am not sure as different windows have different tints and colours.

2004 Citroen C5 2. 0ltr diesel auto VTR and 2011 Bailey Orion 430/4

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I have heard that some of the medium power solar panels (30-50 watts) that have in-built controllers struggle to power up the controller in winter. The beauty of a 10 watt panel is that there is no need for a controller so it is pure current into the battery. The maximum current a 10 watt panel can provide in summer is around 800 m/a and in winter this can drop to 100 m/a or less but should keep the battery topped up and provide power for the alarm and tracker. What effect the window or rooflight would have on power I am not sure as different windows have different tints and colours.

I would have thought that at 100 mA, you would be losing the battle - limited daylight hours, self discharge of the battery plus the load from the alarm. The self discharge rate is generally between 0. 5 and 1 Ah per day, at 100 mA youre putting 0. 1 Ah back in assuming half decent light BUT youre probably only going to see that for 6, maybe 7 hours.

 

This can only end up one way. .........

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What effect the window or rooflight would have on power I am not sure as different windows have different tints and colours.

 

Normal window glass reduces light about 20% I think

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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I have heard that some of the medium power solar panels (30-50 watts) that have in-built controllers struggle to power up the controller in winter. The beauty of a 10 watt panel is that there is no need for a controller so it is pure current into the battery. The maximum current a 10 watt panel can provide in summer is around 800 m/a and in winter this can drop to 100 m/a or less but should keep the battery topped up and provide power for the alarm and tracker. What effect the window or rooflight would have on power I am not sure as different windows have different tints and colours.

 

You lose a lot of power by having the controller stuck on the panel, it should be close to the battery & it should be a good quality one, then it will work the same as a good multistage charger.

 

Ideally the panel should be facing in a southerly direction at an angle (like panels on a house).

Paul B

. .......Mondeo Estate & Elddis Avanté 505 (Tobago)

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Up to three inches of snow on a solar panel may have no real adverse effect.

 

This info was printed in the instruction manual with an Exide solar panel I owned. :)

This is true-- look at my avatar picture, 3" of snow but panels still worked the next day.

david

Skoda Scout 4x4 pulling a coachman Amara 520/4 at 93%---- when full!

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I would have thought that at 100 mA, you would be losing the battle - limited daylight hours, self discharge of the battery plus the load from the alarm. The self discharge rate is generally between 0. 5 and 1 Ah per day, at 100 mA youre putting 0. 1 Ah back in assuming half decent light BUT youre probably only going to see that for 6, maybe 7 hours.

 

This can only end up one way. .........

Not sure this is strictly true as a friend left their car while touring abroard for 3 months and the car started ok on their return. According to your calculations the battery should have been flat. ........... I suppose it depends on the condition of the battery and what is powered when the car is left.

2004 Citroen C5 2. 0ltr diesel auto VTR and 2011 Bailey Orion 430/4

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Not sure this is strictly true as a friend left their car while touring abroard for 3 months and the car started ok on their return. According to your calculations the battery should have been flat. ........... I suppose it depends on the condition of the battery and what is powered when the car is left.

Yes ----- but at what time of year ?

david

Skoda Scout 4x4 pulling a coachman Amara 520/4 at 93%---- when full!

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We have our caravan in storage (outside) and to save me running backward and forward to recharge the battery, we purchased a 40w solar panel and regulator/charger, we mounted the solar panel on the caravan roof wth small wind deflectors and it works fine. If it gets covered by snow I use a soft headed broom to sweep it off. As the battery is kept in a good state of charge I would only have to clear snow perhaps once every other week or two. The caravan next to us has got one of the small solar panels inside his front window, but unfortunately he has tinted windows!!

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Yes ----- but at what time of year ?

david

It was over winter but the car did not have any solar charger so I don't see the point of the question. The point I was trying to make was that the battery did not self discharge at the rate quoted otherwise the car would not have started on their return. Sorry to be pedantic.

2004 Citroen C5 2. 0ltr diesel auto VTR and 2011 Bailey Orion 430/4

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  • 2 weeks later...

Hi, i wonder if anyone can help me out here, I purchased a new Sterling Eccles SE in September, we've been away in it once and are planning to go away this saturday for New Year's Eve. I went to my caravan storage today to sort the van out etc and the battery was completely flat, the alarm wouldn't even beep or in fact sound when i entered. The Van has a 40w solar panel fitted and has been left in direct sunlight so i can't see the point of it to be honest.

Im just wondering if its faulty or this is just the way it goes.

Thanks

Scott

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Hi, i wonder if anyone can help me out here, I purchased a new Sterling Eccles SE in September, we've been away in it once and are planning to go away this saturday for New Year's Eve. I went to my caravan storage today to sort the van out etc and the battery was completely flat, the alarm wouldn't even beep or in fact sound when i entered. The Van has a 40w solar panel fitted and has been left in direct sunlight so i can't see the point of it to be honest.

Im just wondering if its faulty or this is just the way it goes.

Thanks

Scott

 

A 40w panel should keep your battery well charged, either the panel isn't working or something is taking out of the battery more than the panel is putting back in. You need to do some simple checks with a meter to find out whats going on and then take it from there.

John

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I agree that a 40w panel should keep your battery topped up for the alarm. But this time of the year a roof mounted panel won't be putting much into a battery and not for very long each day. Take a look outside and you will see how low and far to the south the sun is I don't think there is such a thing as direct sunlight this time of the year in the UK. We have a 135W panel on our roof when we last went away at the beginning of December I plugged a cheap voltmeter into a 12v cigar lighter socket it was taking until about 10:30am before there was any appreciable increase in the displayed voltage ie it was taking that long before the sun was high enough in the sky to actually allow the panel to work.

 

It may be that your controller is faulty but with a new van to be honest it is more likely to be something draining the battery. When we got our current van we didn't realise that the fridge light is independent of the rest of the 12v supply. So something as simple as that or forgetting to switch your vans powersupply off can flatten a battery so check the obvious.

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A roof mounted solar panel just isn’t going to work in winter. I’m out in the Peak District right now and the sun barely rises above the horizon, let alone high enough to shine on flat roof panels. I’m currently manually positioning a couple of Goal Zero Nomad 13 panels SE in the morning and SW in the evening and only then am I getting 0. 5A. For summer, roof mounted panels are fine. For winter, forget it; either mount them vertically SE/SW or use an alternative source of energy.

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I agree with "tictag's" findings re the dismal performance at this time of the year with horizontally mounted crystalline solar panels. Reportedly amorphous fair better with the reflected light from the clouds, but not tried them.

However mounting vertical or at least 50 odd degrees to the horizontal is also not going to help a lot with an "in storage requirement" in that then the suns across the sky tracking will become a problem; it will only have a brief period facing the optimum way.

Compounding the difficulties will be the low sun angle makes for greater susceptibility to tree shadows.

 

The only viable solution for unattended use IMO is to grossly oversize the panel(s), so that the pathetically low % yield is still enough. Fortunately now the buying cost makes that more viable.

As I said in post #8 we have found a 90 Watt panel mounted careful of shadows at 50 degrees to horizontal pointing due South is working. Possibly an overkill but at current pricings IMO a justified one.

Edited by JTQ
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I agree with "tictag's" findings re the dismal performance at this time of the year with horizontally mounted crystalline solar panels. Reportedly amorphous fair better with the reflected light from the clouds, but not tried them.

However mounting vertical or at least 50 odd degrees to the horizontal is also not going to help a lot with an "in storage requirement" in that then the suns across the sky tracking will become a problem; it will only have a brief period facing the optimum way.

Compounding the difficulties will be the low sun angle makes for greater susceptibility to tree shadows.

 

The only viable solution for unattended use IMO is to grossly oversize the panel(s), so that the pathetically low % yield is still enough. Fortunately now the buying cost makes that more viable.

As I said in post #8 we have found a 90 Watt panel mounted careful of shadows at 50 degrees to horizontal pointing due South is working. Possibly an overkill but at current pricings IMO a justified one.

I have a 150w panel flat mounted on my roof, it manages at best around 1. 7 amps at this time of year and the best I've seen in the summer with a well discharged battery was around 11. 5 amps. Quite happy with what I'm getting, it does maintain the battery nicely and the whole lot cost around £250 and was well worth it.

J

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I have a 150w panel flat mounted on my roof, it manages at best around 1. 7 amps at this time of year and the best I've seen in the summer with a well discharged battery was around 11. 5 amps. Quite happy with what I'm getting, it does maintain the battery nicely and the whole lot cost around £250 and was well worth it.

J

 

Yes John but again that with respect is only achieved by being a gross overkill in most people's eyes, and I suspect not what the OP was offered for a £400 commercially fitted job. For winter solar cell viability "size really matters".

I have found my freestanding panel yields some of its best results in the clear cold winter sun, but it is both rare and fleeting, overall its very disappointing.

Edited by JTQ
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