Portable solar panels vs roof fixture

IMHO get the portable setup with at least 10 metres of thick cable, preferably 20.

This way you can chase the sun and get the most out of your panel/s.

Your van should be in the shade for comfort and hence your solar will be as useless as hip pockets on your undies should you mount it on the roof of the van. Effective solar panels need to be moved many times during the day to maximise their output.

Also give some thought to an amorhous panel (Uni Solar brand). They are bigger for a given output, but are more efficient.

ATB,

Jim.

Mate,

I have a half of a folding panel.

By that I mean that I have one 40 watt framed panel, including the regulator a cable. (BP Solar) I can add another panel and fold it if I need the extra capacity.

My experience with the portable unit is......it works!
Has a couple of legs that fold down and you simply point it towards the sun, or in a direction that the sun falls on the panel as it goes from east to west.

Storage is usually as simple as sticking it under the matress. This works for me with the Camper Trailer and will do the same for a caravan.

Security......Always going to be a problem on occasions. The places I've been I just take the chance. A stainless steel braided cable padlocked to the frame and Camper/Caravan chassis, or A-frame is as practical as anything.

If the mongrels want it, they will find a way of pinching it, or destroying it trying.

hi there
i have an 80 watt fold panel works fine it has a length of cable as already been suggested ihave put anderson plug on end one on van then move to sun my van is pop top when i leave camp i put on roof its not so noticable i also have a regulator beside battery which also works fine
cheers

I have an 80W folding solar panel from Suntech

As you can see the price of $950 (which includes bag and regulayor and cabling is VERY competitive

I have had one for a while now and it workd VERY well

100W minimum for fridges.

I have done tests and only the 50L and under will run off 80W.

I have even stopped producing the 80w Bi-folds.

Regards

Derek.

G'day not sure what others think but i know what i think from using a 80 watt bp panel for portable use with my home made stand and must say that it works fine Keeps up with a 32 and 39 L engels for my 2 week camping trips on a 100 amp H . panel cost me $650 cable $60 from whitworks and regulator from bcf (on special at the time for $29) home made stand i used bits and pieces from the curbside clean up. Used a old baby rocker works a treat and pulls apart for transport to see here is the link copy and paste Site Link .For security all i did was goto a wire cable place and got a SS cable made up. As already stated if they want it they will take it or destroy it trying.

Fold up great for space, but i have a camper and place it in there when on the move, not like it is in there when ya camping etc. Follow the sun and all should be well, mind you i have a honda geny for back up but have never had to use it !! (NOT MUCH RAIN AROUND LOL)

Any question ask i will help where i can.

Lifeisgood,

We bought an 80w BP panel,cable and morningstar regulator off Derek. Used 50mm angle alloy brackets to mount on poptop roof. Set it up so as it is removable.
Bolts slide thru the front angle brackets and padbolts slide thru the rear angle brackets. Put 2 padlocks on,secure as. Post your email and i can send you some installation photos.

Regards
Greg

Lifeisgood,

I have 2 x 80w BP panels wired up together with regulator that tells me what wattage, amps, current i am drawing, and how my battery is charging, tells u everything. I run a 110 waeco and 2 deep cycle batteries. Still , i always carry a multi metre. The panels are on adjustable home made stands, where i can move or put them to suit the sun. To be on the safe side, i chain mine up to the A frame of the trailer. I had a weather proof, insulated bag made for them for travelling which stays on the roof rack of the camper trailer. Bought it all from Jaycar in Frankston.

cheers, Lance

To calculate what size solar panel you need see the example and methodology below:

1) Observe your fridge for a couple of duty cycles - Set your fridge up in a typical place such as you would when camping. Do your test at an average time of the day so far as ambient temperature goes (not the hottest, nor the coolest part of the day. Load the fridge with similar stuff to what you would take camping. Set the thermostat to the temperature you normally would when camping. Allow an hour or two for the fridge to settle - preferably running on mains supply if available. Now record the running and non running time of the fridge for two or three cycles.

Typically you might get a 20% - 30% duty cycle.

2) Find out the typical current requirement of the fridge. If you don't have a digital voltmeter just find out the wattage rating specified for the fridge and divide it by 12. For example if the manufacturer claims the fridge is 36W, then your current demand will be near to 3 Amps.

3) Multiply the current demand by the duty cycle by 24 (hours in a day)

eg 3 Amps x 30% x 24 hours = 21.6 Amp Hours per day.

4) Regardless of what battery capacity you have, your solar panel needs to replace the amount in step 3 in the available sunlight hours if you are not to drain your battery. So when choosing a panel, look at its rated wattage. Take 10% from that figure because the rated wattage is under optimal conditions and not achievable in reality. Let's use the example of a 40 Watt panel:

40W x 90% (efficiency) = 36 Watts.

36 Watts divided by the nominal output voltage (13.6 Volts or thereabouts) will give the current output of the panel.

eg 36 / 13.6 = 2.65 Amps.

Multiply this by the expected hours of sunshine. This is a bit problematic, but if you used 6 hours as a typical figure you would be in the ball park (although personally I think that is more than you would experience over time in southern Australia).

So, 2.65 Amps x 6 Hours = 15.9 Amp Hours.

So, we calculated that we need 21.6 AH and we can supply 15.9 AH (Just as well that you have that battery!)

Ideally you shouldn't use a depth of discharge for a battery of more than about 50% if you are to maintain a good cost versus life expectancy equation.

So if you had a 70 AH battery (which would typically have about 3% internal losses - but we'll ignore those), then ideally you should not reduce your Amp Hour capacity to less than 35 AH.

In our example, 35 AH / 5.7 AH shortfall each day (with a 40W panel) = 6.1 days.

6.1 days of running time. Now all of these figures have been pretty generous. We didn't allow for extra running of the fridge after it has been opened, or new goods have been added that need to be cooled (more beer, for instance). Nor have we taken into account shady/cloudy periods. We didn't allow for any other uses such as lights, fans etc..... also drawing extra current. We didn't allow for hot ambient temperatures.

This is purely subjective, but I suspect the true figure would be closer to 4 days. Sure, you could run the fridge for longer than this, but in doing so you start to dramatically reduce the life of your battery too.

You could repeat this exercise for panels of other ratings such as 60W, 80W or more. Each higher wattage you calculate will reduce the shortfall in your battery. Ideally you should aim for a small surplus of energy. (You never know when you might just need a charged battery to start the car!)

OK, these figures are approximate, but close to reality, so please, no-one jump down my neck and reply with "I get this" or "I get that". I'm just trying to simplify it for those who would like to know how to work it out - using reasonable figures.

Hi. I have my panels on the roof of the wagon. That way when I leave camp the
panels go with me. I have made a lead up to plug into the camper battery from the
panels to top them up. Have my 2x40L Engels in the wagon.so don't use much power from camper battery only lights. Also T
the engel I use as a freezer I turn back to 1.5 setting when I stop getting power from the
sun and do not open it
.

I have a 85w Panel {Suntech} mounted on frame roof rack at 25-30 degrees angle facing the front and running accross vehicle. Panel can be removed by wingnuts from frame. Have canvas padded cover for added protection. however rarely use and initially feared rock damage however travelled thousands kms, dirt, rough and rocky no problems. Can use panel when vehicle in motion to charge two static "lifeline 100 amp batteries" inside vehicle. always use regulator on panel stops any damage over charging. This set up took a bit of work however "highly reccommended". My set up is on a toyota troopie. further have small locking device to prevent theft. However if they want it (panel) they have to cut to remove it.
Hope this helps. Further you have to carry the panel somehow so why not mount it and use it. Regards.....Harro......

The way the missus and kids are in and out of our 110L Waeco, I think I need a 3000 watt panel... Anyone know where I can get one under $1k...??? ;-)~

I don't want to hi jack the tread but I have noticed some use BP panels and others use Suntech (i think is the name) i assume they are only brand names. As with most things you get what you pay for so I assume there is a quality issue between panels so how do you pick a good solar panel?

Brian

Hi,I went throught the solar panel idea but in the end brought a genenator,wired a 20amp three stage battery charger into the Toyota plug in the caravan if the battery is low otherwise just charge the frig batteries work like a dream being on the road for over twelve month.Bat.

Hi Lifeisgood,What we found up north it can be be very hot even in the winter months and bush camping it nice to have the air to put on.You need 2kva to run it and my Honda in very hot condition found it hard going,so top the batteries up then. Super Cheap have a 17amp two stage charger for $200, Australia made see a lot around good product.Allso the honda has a 8amp out let.People I spoke to long term travellers all say If you can keep the battery top up they will last for years.As you say everone has a idea but I found running 2 frigdes battery in the Toyota and allso being able to use the caravan battery for fridge, running the generator was not a problem.Just used a Anderson plug,well have a great trip.Bat