Thread: Solar Panel questions

Ive got a single solar panel that in townsville had enough guts about it to keep my engle going on a normal rover start battery (94ish disco) for ever...

I'll check the actual wattage of it but from memory its a 80/85 watt panel.

keep em clean and keep em angled into the sun and you'll get the best bang for your buck.

A good solar regulator is a must.

Jimmy,
I have a rack over the front part of the roof on my 110 County with 3x 37W solar panels on board (any size or combination of panels will do so long as they can push about 6A in in bright sun). You biggest problem straight up is the age of your Engel. Old Engels tend to be just as reliable as new ones but draw more current. More recent models draw much less current once the fridge is cold.

The simplest way if you are mostly base camping is to get a couple of PV panels, say 85W and fit them up with a hinge so they open/close like a book and you can put them out away from the car in the sun propped on a stick. You wander out every couple of hours to optimise the bearing on the sun but otherwise you just sit in the shade enjoying your beer.

The panels closed up can be stowed on the roof rack for travelling. Some people say fold them galss inwards, but I disagree, fold them glass outwards as the glass is tough but the plastic film on the back side isn't. You need to stow them so they can't rub on hard things.

You will need a charge controller between the panels and the battery. Your local solar guy can provide something suitable. Also need reasonably heavy cables, say 2.5mm2 min to minimise voltage drop.

Khun Moo

Have seen some permanently mounted on Defender between where the roof rack ends, near the back of the front door, with a bracket made of the front of the rack and a light bar at the front of the roof angled down. This is what I hope to do when funds allow.

I have often thought of getting solar panels but have seen people with them at camps and they seem to be fairly high maintenance. ie keeping them angled right, cleaning the glass, and they are reluctant to leave camp in case the panel gets pinched.

I guess if they were permanently bolted to something ( camper trailer or the car ) with some way of changing the angle it would be OK.

Jaycar have a solar regulator 20 amp for about $60.

have a look at this thread, some useful info

http://www.aulro.com/afvb/showthread...ighlight=solar


i have a 65W mounted on my defender, while its good as a wind deflector it can be a pain having to move the car evey couple of hours to get most out of the sun. i would take it off but its a pain to store in the car cause how big it is

does your engle have a plate on it indicating its current draw, i have a new and an old and they both cycle around 50% of the time. if you look at worst case it draws 5amp/hour for 50% of the time thats 2.5amp/hour x 24hrs/day = 60amp out of your battery. you need to put 60amp back in during daylight. thats all worst case off course

I have absolutly no clue about these solar panels and as such have a few questions.

I've seen some for sale over here in the China made section of a local mall.
Is there a voltage preference for them? ie, 12Volt, 110volts, 240volts etc?
What about the connections to the panels? Do they need to be waterproofed etc. I've seen folk with solar panels laying flat on the roofrack...what about surface dirt etc...can that damage these panels or are they pretty robust?

What questions should I be asking before buying a panel? I note that there are different types of cells, black, blue etc...which are best and why?

Thanks & regards.

S.

Originally Posted by streaky

I have absolutly no clue about these solar panels and as such have a few questions.

I've seen some for sale over here in the China made section of a local mall.
Is there a voltage preference for them? ie, 12Volt, 110volts, 240volts etc?
What about the connections to the panels? Do they need to be waterproofed etc. I've seen folk with solar panels laying flat on the roofrack...what about surface dirt etc...can that damage these panels or are they pretty robust?

What questions should I be asking before buying a panel? I note that there are different types of cells, black, blue etc...which are best and why?

Thanks & regards.

S.

Solar panels come (for practical purposes) in two voltages, both nominally twelve volts, but one designed to charge a 12v battery without a regulator, and one designed for use with a regulator (preferred). The other important figure is the nominal wattage, varying from about 5 to about 100 (not sure what the current largest one is, it keeps changing), which is very closely proportional to the area of the panel.

They come in two basic types, amorphous and crystalline silicon, being cheaper and more efficient respectively. They can be mounted on either glass or plastic, the former standing exposure to the sun better but glass is breakable and hence not the best for travelling with.

Almost all of them are completely weatherproof (except for ones intended to be built into equipment). The colour is irrelevant, although it does indicate differences in type of silicon or construction details.

Dirt on the surface decreases the efficiency of them, but they do not have to be scrupulously clean. The efficiency is mainly dependent on their angle relative to the sunlight - think of the sine of the angle, as it varies from 90 degrees. Depending on their construction the output can be either slightly affected or completely stopped by shadow on part of the panel, and this is one difference that may be worth looking at.

A lot is made of differences in efficiency, but for most applications, if it is reflected in price, it is irrelevant - lower efficiency simply means more area needed. (really becomes important in, for example, a solar car where the whole of the top of the car is covered with solar panels!)

John