Solar panels - quantity discount?

Biggles said:
I am not dishing solar, and in an ideal world we would all live off it.

But here's my 2 penneth. I have 2 110a/h led lighting, no TV, 1000w inverter for laptops and iPads and phone charging.

I once left my 12v fridge on and in the morning we had flat batteries. I started the engine for 20 minutes and I did another 4 days without moving (festival).

So in conclusion 20 mins of tick over charging will cost next to nothing and if done at the right time will not upset anyone nearby, and believe me at a festival they pack us in.
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Alternator on tick over will probably give about 10-15 amps once the the initial high charging current settles after a minute or so. But be on the generous side and say 20 A.

20 amps at 14 V for 1/2 an hour = 20x14x0.5 = 140Wh

Although it's a useful top up charge, and may last a good while if your usage was low, it wont give you the charge an 80W solar panel will give in a day (350 Wh ?)

Another thing to consider, is if your solar panel keeps your leisure battery topped up, when you drive off normally, it wont draw a big current from the alternator which means the alternator belt wont drag on the engine so much and you'll get increased mpg. This is kind of a hidden benefit as it seems on the surface you get a "free" recharge every time you drive, but you will pay for it for a while by slightly poorer mpg especially if your leisure battery was very flat.

I'd agree though it will take some time to recover your solar installation cost in diesel costs! Even for full time use it may take a couple of years, longer if you only use your van some of the year.
 
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To me the big benefit of using solar panels is the fact that it's noise free, and non-polluting.

I used to live on a narrow boat, and had two large panels on the roof. I never needed to run the engine unless I was going somewhere, and that was a huge plus point.

So if you're out in the sticks with your 'van, you sit there as long as you like without disturbing the peace :)
 
Canalsman said:
Any news, Phil?

Thanks

Chris
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No, I am going to try some other suppliers on Monday but I need a better idea of what purchase value we are looking at.

I also want to find someone who also does flexible panels as I would prefer them to having the framed type.
 
Solar

I would be interested in 2 x 100w panels. (And will add a 3rd depending on how these perform).

The ones below seem to be good value at about £200 each. I'm happy to go with previous advice that this is the kind of value / quality to go for. I would appreciate buying together with others, from a trusted supplier.

New 100 Watt Mono Crystalline PV Solar Panel 100 W 12 V | eBay

Due to limited roof space, I like the idea that these panels are squeezing an extra 20w into the same dimensions as many of the 80w panels: 1196 x 554 x 35 (mm).

By the way, these look like good regulators. They have PulseWidthModulation to get more charge from the panels, and according to the reviewer, they use a 3 step battery charging system.

NEW 360W 12V 30A SOLAR PANEL CHARGE REGULATOR BATTERY: Amazon.co.uk: Kitchen & Home

Any opinions on these selections welcome...
 
That seller has become too dear. At the start of the year they did 80 watt at £139 delivered and by Spring had risen to £179 PLUS P&P shop around they'll have to come down if people shop sensibly
 
About these charge regulators:-

I was recently at a talk held at the SBMCC AGM

The chap talking on solar said that the cheep controlers were a waste of money. He had taken some apart and some had nothing in but a diode. He siad that nothin under about £130 was worth considering especially when you were getting into the bigger panels.

I don't think he had an adgender for this line.

The more expensive ones have a transformer or whatever in them to make the higer voltage output into higher amp charge rate. In his tests a good controler could inrease the charge output of a panel by upto 30%, or if you like enable you to buy 30% smaller.

Just passing it on. Can't personally validate it.

ETA. He also said Poly panels should be just over £1 per watt and Mono well under £2.00 per watt and prices were governed by the dollar which is the international trading currency for solar pannels.
 
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Firefox said:
Alternator on tick over will probably give about 10-15 amps once the the initial high charging current settles after a minute or so. But be on the generous side and say 20 A.

20 amps at 14 V for 1/2 an hour = 20x14x0.5 = 140Wh

Although it's a useful top up charge, and may last a good while if your usage was low, it wont give you the charge an 80W solar panel will give in a day (350 Wh ?)

Another thing to consider, is if your solar panel keeps your leisure battery topped up, when you drive off normally, it wont draw a big current from the alternator which means the alternator belt wont drag on the engine so much and you'll get increased mpg. This is kind of a hidden benefit as it seems on the surface you get a "free" recharge every time you drive, but you will pay for it for a while by slightly poorer mpg especially if your leisure battery was very flat.

I'd agree though it will take some time to recover your solar installation cost in diesel costs! Even for full time use it may take a couple of years, longer if you only use your van some of the year.
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Being an ex ambulance it has a massive 175amp alternator and some very good split charging control. So maybe I am a bit spoilt.
 
That's interesting information on regulators, Biggles.

I've got a Kemco from Maplins. Only a £20 job. I'll let people know how it performs. I just wonder how many users have got a controller costing £130! I bet it's not many.

I have read that some regulators give a pulsing which inverters don't like, which causes the inverter to shut off while the solar panel is working. I don't know if mine does that as I only glued the panel on today, I haven't wired it up yet. But I plan on putting in a switch on my control panel so I can turn the solar panel off if necessary.
 
there is some interesting explanation about different types of solar regulator here: Sterling Power Products: Solar Regulator Information

i also had an email conversation with charles sterling about battery-battery and alternator-battery chargers. he said that if i had 2 batteries in my bank then it would only really be worth getting the battery-battery charger which is 50A, but if i had 4 batteries in the bank, then they would be able to "eat" closer to the 150A that my merc's alternator is capable of putting out, and hence it would then be worth getting an alternator-battery charger.

love all that science.
 
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Charles is a bit of a ledgend in the boating world. His products receive mixed reviews, however he does himself no good in term of personality. I speak from hearsay but seems he talks sence and his products are generally good, but most people find him personably less than "their cup of tea". Maybe the curse of a genious?

As for inverters not liking it? My guess is if its a cheep but otherwise very servicable unit the electronics (or lack of) will not be capable of handeling anything other than a nice flat stable DC input.

In my boat I have 1280a/h of battery made up of 6 x 2.1v deep cycle traction led acid cells poweing a Victron 3000w PSW inverter (6000w peak). I have been working on the boat all week off grid with lights heavy 2000w + power tools radio and it is still showing 12.8v. Of course you would never have this set up on a MH unless it was coach size as the batteries weigh in at 350kg and the inverter at 18kg.

On the MH I have a cheepo 1000w MSW inverter which I use for charging stuff while out and about. Mostly the lap top and the iPads as these wont fully charge off a 12v cigar lighter adaptor. At first I used to switch it off when done, but on no load it seems to draw so little I don't bother now.
 
Rather more than a diode in mine. If this was imported and marked up by a UK dealer it would be VERY much more than £130 but I have now bought 3 of these from Taiwan via ebay at £69 delivered each.
MPPT-L.jpg

mppt-103-L.jpg
 
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Looks like a nice bit of kit. Not that I know much about that sort of thing. Certainly much more than just a diode.
 
I have a CTEK D250S between my alternator and inverter batteries to ensure that get charged to 100% and are maintained correctly. CTEK also do a D250S dual which has a solar input as well.

CTEK D250S Dual Car Battery Charger - the smartest battery chargers in the world!

Although this product is not cheap, you will get the most from your battery capacity and have the option for solar and alternator.

They also do a smart pass:

CTEK Smartpass Car Battery Charger - the smartest battery chargers in the world!

When the first battery bank is fully charged (habitation) it will the pass the charge to the second bank (inverter)

installationsbeispiel_lb.jpg
 
Here's a photo of how I fixed my 90W panel yesterday:

Solarpanelpic.jpg

Click on thumbnail for larger.

Basically it is two 50x25 aluminium angles with 4 number 6mm zinc roofing bolts each side. The angles are stuck down with Sikaflex 512 to avoid drilling the roof. Drainage holes provided make sure no water can be trapped under the panel as it is a sloping, cambered, corrugated roof. The angles fix the panels and are high enough to allow for the slope on the roof.

If you want to see a video explaining more, and a bit about the regulator I have done one here:

21. Solar Panels Part 1 - YouTube

I'll probably do a part 2 when I've completed the project.
 
Yes I could have used 4 or 5mm bolts, but those 6mm ones were the smallest size I could buy in Wickes at that time, LOL.

I could even have used Tek screws but I wanted a large head on the bolt to clamp everything tight and stop it all moving around as I was drilling close to both the edge of the frame and the angle to get the elevation high enough on the angle so the panel clears the crown of the cambered roof by 15-20mm in the middle, so there was some method in my madness.

Fitting the panels on a flat coachbuilt roof is a bit easier as the camber, corrugations, and drainage are not issues.
 
Hello Techno! That charge controller looks good,do you have a link for it please :wave:
 
Firefox said:
Yes I could have used 4 or 5mm bolts, but those 6mm ones were the smallest size I could buy in Wickes at that time, LOL.

I could even have used Tek screws but I wanted a large head on the bolt to clamp everything tight and stop it all moving around as I was drilling close to both the edge of the frame and the angle to get the elevation high enough on the angle so the panel clears the crown of the cambered roof by 15-20mm in the middle, so there was some method in my madness.

Fitting the panels on a flat coachbuilt roof is a bit easier as the camber, corrugations, and drainage are not issues.
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No I said RIVETS lol No need for duck tape nor having to locate and tighten a back nut :)
 
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