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Solar panels. - What's next?


sshortcircuit

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The thread above is well worth a read ... I did consider solar but, for reasons given in my post on 2 leisure batteries (copied below) decided against the option.

 

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I spend a number of months wildcamping every year in the UK and EU (VW T5 having all LED lights, laptop, tv and Waeco fridge and a 110 AH leisure battery). Over many years I have never had a flat leisure battery ! Why .... I am juditious with the fridge use (generally having it on and cooling when motoring but not when static) ... and ... either I travel every day (even if its just to the beach or shops) or, if I'm immobile for more than a day, I run the engine for 1/2 hr to charge the battery.

Do the calculation ... diesel burn for 1/2 hr every day or two when you do not move the van (this circumstance is unusual for me - what about you ... how often are you totally static for days on end?) cost=? Calculate total extra diesel used/year on extra top up charging. Then work out how much diesel you can buy for the cost of a good, fitted solar panel (£400 ???)

For my van and type of usage I calculate it would take me 15-20 years before the solar paid for itself !!!

I'll stick to pottering down to the beach and shops every day or so thanx

This view is at variance with that expressed on page 186 of the Jan 2012 MMM magazine ....

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There are 2 main types of solar panel which can be used on a motorhome - Mono or Polycrystaline. You will see a lot of hype telling you that the mono gives more energy per sq meter than a poly. There is in fact very little difference. A mono is cut from a single crystal and therefore, by the nature of its shape, usually, loses a bit of the available space. A Poly can be a mass of small crystals and can be formed into neat squares. You can spot the difference on a panel where the mono has more white bits showing with rounded corners and a poly is almost devoid of white bits. The lack of white bits means that more crystal per sq meter is exposed to the light and therefore for the same overall sq meter of panel you will get almost the same amount of power.

 

It comes down to what your requirements are. As has already been said, if you want to be as independent as possible of mains power, go for the largest amount of solar real estate you can fit / afford but make sure you also have the battery capacity to store all that energy. You will also need to look at the implications to your available payload of adding solar panels and batteries.

 

We don't have a problem with payload and have 2 x 120w poly panels and 3 x 140Ah batteries. We use our 'van throughout the year and in summer we never need a hook up although we are fairly heavy power users (satellite tv, 2 laptops, lighting etc). In winter in Portugal we often stay in one place for a few weeks at a time and use a motorbike for travel to shops etc. To supplement the 2 roof solars I have a 60w panel with a stand I made for it. This is placed outside facing the low sun and boosts the batteries sufficiently that we don't need to use a genny.

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Give some thought to the controller/regulator. The newer technology offers some advantages and some offer real if modest gains in lower light levels. Also some have provision for adding extra panels if needed and even oversplill outlets for maintaining the starter battery. You can of course spend a fortune on the very best but even modestly priced units may offer some of these features. Equally some new product will still be based on older technology. Naturally enough we use the brand we sell but there are a number of good ones to choose from and doubtless you'll get a number of opinions about those.

 

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Hi,

 

I having been considering changing to a MPPT controller, my solar panel supplier in Berlin has tested some of the cheap MPPT controllers and has come back with some alarming results. Apparently it is common practise with the chinese manufacture to duplicate their competitors designs.

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sshortcircuit - 2012-01-05 9:52 PM

 

Will be fitting a solar panel this year. To the experts, what's the most efficient and is there anything just round the corner I should wait on?

 

As you are not a million miles from me can I tell you what we have done on our last two vans. We've gone to stay at Bellingham C&CC site in Northumberland. Stephen Gilmour of Aire & Sun has fitted an 80w BP solar panel to our vans there....he will come to the site. Just check first with the Warden, but its usually fine - they are used to it.

 

We have no connection with Stephen/Aire and Sun other than being very satisfied (returning) customers. For example he uses high grade cable (not bell wire!) to reduce voltage drop. He has in the past come to Melrose CC site but we had to pay a small surcharge for his travel time. Used to offer a reduced installation charge during the winter....maybe still does.

 

Last panel fitted early April 2011 cost about £450 from memory, installed, tested etc.

 

http://www.aireandsun.co.uk/index.php

 

Arthur

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For a different solar panel you might consider fitting a combined solar panel and satellite dish - assuming of course that you haven't got either yet.

 

Due to the lack of flat roof space on my MH I had a Oyster Samy Solar Plus system fitted this year. See it at: http://www.ten-haaft.de/e/produkte_samysolar.html

 

It's a great bit of well made kit which uses the satellite/GPS system to line up the solar panel at 90 degrees to the sun. This means that the smaller 60cm square panel is highly efficient. Even in the 'parked' horizontal position it charges the leisure battery more than adequately for my needs. It can also be programmed to lock onto the sun at dawn and track it all day. The sat dish is 65cm so pretty good in northern europe. Clever stuff!

 

Downside is that they are not cheap but not too much dearer than buying separate systems and only one fitting fee. Food for thought?

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Thanks for all the posts which I have found informative. Unfortunately it does not look like there is a new invention just round the corner which will double the output of panels.

 

I currently have 2 X 110A/h however when static for some time they do deplete. Not meaning to to upset but unless you spend a fortune on a special relay unit, running the engine is only ensuring the vehicle battery is well charged up and very inefficiently charging the leisure battery. I would use my generator in that situation. I also understand the point of a good controller and installation to make the most efficient use what has been generated.

 

Thanks again to all

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sshortcircuit - 2012-01-05 9:52 PM

 

Will be fitting a solar panel this year. To the experts, what's the most efficient and is there anything just round the corner I should wait on?

 

We don't know of anything coming up but the dual dish/panel system should give you more power than a flat panel - if it is sunny you don't want to watch TV anyway.

 

P&L

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I do have an expensive split charge unit (not ex Ebay!) ... and at an alternator output of 95 A and an always fully charged heavy duty engine battery ... the Leisure battery charges very quickly ... the engine is my generator ... not much free space in a VW T5 !!! Travel light travel far my mum used to say ....

 

sshortcircuit - 2012-01-06 5:10 PM

 

Thanks for all the posts which I have found informative. Unfortunately it does not look like there is a new invention just round the corner which will double the output of panels.

 

I currently have 2 X 110A/h however when static for some time they do deplete. Not meaning to to upset but unless you spend a fortune on a special relay unit, running the engine is only ensuring the vehicle battery is well charged up and very inefficiently charging the leisure battery. I would use my generator in that situation. I also understand the point of a good controller and installation to make the most efficient use what has been generated.

 

Thanks again to all

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sshortcircuit

We bought a portable solar panel last year from All Solar in Stonehaven. Comes as a fold out case with regulator incorporated. We've been very happy with it. Like some others we spend long periods in the one place and find the solar panel very useful. We debated whether to have on fitted but decided that a portable one could be used on another unit if needs be. Not much weight in it and also comes with a protective bag. Don't have their number or website to hand but easily found on line I think.

ike

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I fiited a 120 watt solar panel connected to 10amp controller and two 105 amp leisure batteries.

 

I do all wild camping and used to use a generator but since installing the panel i have more than enough power soileave it at home.

 

In the summer by midday the batteries are at full charge.

 

I convert to AC through a 1600watt inverter which powers the 21 inch lcd tv ,sky box and a vacum cleaner!

 

I wish i had done it long ago.

 

Pete

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The performance of mono and multi panels is today very similar so its hardly worth paying any extra for mono. Fit the biggest solar panel you have space for and can afford. If this is less than 80 watts then save up a bit more cash. 80 watts minimum.

Buy a panel from a well respected manufacturer. BP panels from Marlec Engineering work well.

You can seldom justify the cost of solar panels on a cost basis, so use the same arguement you put forward to justify buying the motorhome and it will be easy.

MPPT voltage regulators do provide a little more output and the Votronic model seems to work well based on my short period of testing early winter. But a regulator is a must. If for the same money you can buy a normal regulator but a panel 20 watts bigger then that will be the better option. (Its easy to fit a more expensive regulator later)

 

Lastly minimise your electrical loading by having LED lighting for example and always look at maximising the size of your battery bank first as this is by far the lowest cost way of extending wild camping adventures.

 

C.

 

 

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Having looked through the various postings I am grateful for the input. I have come to the conclusion that solar power is a bit hit or miss so dependant on the weather conditions which can be so variable. I consider I should follow along Buxtons path and make use of the built in charger, ie vehicle alternator, and will now search for an proper split charger relay??? and would be grateful for any suggestions as to which unit to install.

 

 

 

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sshortcircuit - 2012-01-07 10:39 PM

 

Having looked through the various postings I am grateful for the input. I have come to the conclusion that solar power is a bit hit or miss so dependant on the weather conditions which can be so variable.

 

In twenty years experiance of using solar (twelve on van and eight previously on boats) we've been let down I think once maybe twice, but guess what, we have the engine alternator as backup. Solar will not be answer for everyone, esp. if you go to sites with hookup, but would not be without it, fully automatic, no faffing about worrying if the electrics will work or not, no starting engine and/or driving about just to charge batteries, just get on and enjoy life.

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Guest 1footinthegrave

Take a look at your usage first would be my advice, we have replaced all of our halogen lighting with smd's, we can run all of our lights now for less current drain than just one halogen, and a newly acquired 12 volt LED combo tv/ dvd consumes just 1.5 amps. Just wish we had a convector type heater instead of the Truma blow heater system which to my mind for all except the largest of vans is pointless and creates a totally unnecessary extra demand on the batteries.

 

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Thanks for the suggestions onefoot. I have changed to LED lighting and have a low power tv however as you say the blow air heating really consumes power. Had thought of a convector type gas heater but just no suitable place for it to be fitted.

 

It looks like I will be considering a substitute relay system to make use of the vehicle's alternator, possibly a solar panel, but have yet to be convinced of there effectiveness with current technology, hence my initial posting.

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Guest 1footinthegrave
I'm a little confused, surely your vehicle already has a split charging relay to charge the leisure batteries on the move, or am I missing something.
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1footinthegrave - 2012-01-09 6:02 PM

 

I'm a little confused, surely your vehicle already has a split charging relay to charge the leisure batteries on the move, or am I missing something.

 

Yes a relay is fitted however the output from the alternator is controlled by the charge state of the starter battery. Once the vehicle is running it will take a very short time to charge the vehicle battery and then the output from the alternator is considerable reduced which would then take hours and hours to charge the leisure battery. I understand units are available that can control the output from the alternator to provide a high output for the leisure battery thus reducing the charge time.

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Guest 1footinthegrave
Well there you go,something else I've learned, do you ever stop learning. I just assumed the alternator would continue belting out the amps. Presumably if all the batteries were linked together that would happen, then maybe an isolator for main engine battery when parked up so that you always had engine starting ability, or is that not an option I wonder. No doubt someone will be along in a minute to baffle me with science. (lol)
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Guest 1footinthegrave
I must a bit thick, or simply do not understand the mysteries of vehicle charging systems, but why could you not use some heavy duty cable with an isolator switch direct to the engine starter battery as I suggested, as long as there was no attempt to use the starter when connected to the leisure batteries wouldn't it do the same job ? Bemused as ever. :-|
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wish i had fitted solar panels years ago. at mmm shows stopping for five days never get a flat battery.

every time we stop on a camp site and don't use the hook up that's a saving of £3 to £4  .40 days on aires in france no hook up .lost count of number of days i have saved

if you are good at diy then buy of ebay about £200  will get you up and running .

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