solar roof car panel

I'm looking at upgrading my solar panel on top of my troopy as the 80w panel currently up there isn't keeping up with the demand of the fridge and a few led lights that I turn on occasionally.

The solar panel has sustained a rock and now has a freckled glass appearance so she has to go. Mind up she still is pumping juice back into the 100ah battery.

so can we get a 150w panel to fit onto of the cab of the troopy?

might have to install a couple more batteries to be sure?

just putting it out there.

regards
oneday

One 80 watter is a bit lean on to keep a fridge going in Pilbara temperatures. I find at least 120 watts is required and that's right on the limit. But it's easy to work out how much wattage you'll need. But remember to bank on a panel only delivering about 85% of its rated output into the battery because of heat, wiring losses, etc.

Why not get two 80 watters? That way if one get's damaged the whole panel isn't a write off. I do it that way. Solar panel set ups have to be a bit balanced. Too many panels and not enough batteries is wasting money on panels and the other way round - more batteries with less panels, won't keep up with demand from the fridge, lights etc. It's as much a storage problem as it is a generation problem.

Two 80 waters and two big Optima AGM spiral batteries keep my 40 litre Engel fridge/freezer going no probs - except for a couple of consecutive cloudy days. To get over that I have the genny obviously but also have a Redarc switching system to back up the panels. So when I'm running around or just doing my daily "will it start?" check each morning, the fridge batteries get a bit of a top up.

Only had a cuppla failures, A couple when the old Autofridge was on it's last legs - (get the meat out and spend all day cooking it before it went off) - and the odd issue with blown fuses due to bad connections in the panel circuits.

A good panel regulator is a must. Don't get a cheap one and make sure ya it shows all the readings with two day history so ya can work out what's going on when the system plays up occasionally.

Good reading can be had in the books by Collyn Rivers. He's the guru on panel stuff, loadings and wiring etc:

http://www.bing.com/search?q=collin+rivers+solar+installation&src=IE-SearchBox&FORM=IE10SR

I use Altronics for all my stuff, good postal service and great back up if the goods prove faulty, which isn't often:

http://www.altronics.com.au/

HTH!

Hi Ray
I run 2 x 100w ontop of the new 76, runs into a 105 A/hr AGM. Keeps 40l engel going 24/7.
CTEK D250S Dual for charger. Does solar when car not running, switches to alternator when running.
Cheers
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nice setup

Flyrock, does you vehicle solars fold up when traveling so you can stack the roof rack?

Yes Pete, I designed it with piano hinge across the front and Stainless overcentre lockable latches on either side.
I have a waterproof roof bag that fits in the space under which I can place small, light items.
Cheers
Phil

yep nice set up--that's about were I'm heading--200w panels

the good thing about the troopy is that u can utilise the immediate area above the cabin, but I will be putting a piece of clear acrylic over the panel to stop any breakage of the glass.

I gather these 100w panels are from fleabay?

regards
oneday

Be careful with eBay panels. They're often sub standard and don't deliver the "whatage" (?) they say. "Panels ain't panels"

HEY COMRADE
you will need 3 x 200 w panels if you wanna run the disco lights like you and steve had at meeka ??????


nice set up flyrock

cheers the speciman

Quick way to test the power output on a panel. Useful if buying used panels or you just wanna check yours from time as the outdrops about 5% from new after the first year or so. After that, it has a life of about 25 years but slowly degrades to zilch over that period.

Tilt the panel to about 22 degrees into the sun.

Turn the panel so it's perpendicular to the sun - look at the shadow on make sure it's the straightest shadow you can achieve. That way the panel will be at max output.

Get a voltmeter and switch it at least the "20 volt" setting. More would be better, you may need to go greater than "20 volts" if the reading goes off scale during the test.

Making sure that the pos and neg wires never touch each other, put the "Pos" lead on the panel to the "Pos" lead on the meter, put the "Neg" lead ditto to the "Neg" lead on the meter.

Check the reading. You should be seeing between 19 volts and 21 volts.

OK? Done? that's the voltage output done. BUT you'll always get a voltage output of something even if the panel is on it's last legs. Amps are the important thing.

Switch the multi-meter to "amps" and you may need to swap the test leads around at this point. You also need to be careful what you do from now on as you can blow the meter if you get it wrong.

Most meters only go to about "20 amps" max on the stuff that we "normal" people use. So that's the max we can tolerate. So how do we know what the max SHOULD be?

"Wattage" equals "volts times amps". So working it backwards,,,,if your panel is say "100 watt panel" and your panel is pushing out "20 volts", then it's a " 5 amp panel at 20 volts". So the max that panel can out out AT 20 VOLTS is 5 amps. It will change when connected into a 12 volt system - more later.

So we now know the ampage won't blow the meter.

So when you have yer meter set up for "amps" connect the wires again as above - "Pos to Pos" and "Neg to Neg". Be warned to give a loose connection that you can pull away and disconnect quickly. A multimeter will only tolerate amps for a few seconds befre you "smoke it". So as soon as you have the MAX amps output on the meter, get the wires off it quick.

That amp figure prove the panel actually has an amp output, it can prove if the panel is relatively new or old 'cos if the amp output is nowhere near what the seller says it is or what it should be, then he's taking the piss and it's on old panel.


You will always get a "volts" reading but that doesn't mean anything on its own. Its the amps reading that's important.

So if you have a "100 watt" panel, you should get 20 volts (typically) and 5 amps output, or thereabouts. But when you connect a panel into a 12 volt system you need a regulator or you'll blow the battery pretty quick.

So connect the regulator to the battery FIRST,,,,,,,,,this is important,,,,,,,,,,get the polarity right, check it and don't be a dick like me that actually blew a brand new regulator 'cos I was distracted with the missus yakking at me at the time.

Then, and only then connect the  panel to the regulator - again, check the wiring polarity. These things can be delicate little buggers. BUT - before you connect everything as above, turn the panel away from the sun or cover it with a towel or sack or such like.

When it's all connected, turn it into the sun, leave it all for about 60 minutes and check the output using the regulator view screen.

If ya have a "100 watt" panel you won't get "100 watts divided by 12 volts and get 8.3 amps". This is due to the "85% factor" where you get a approx. loss of 15% due to heat in the panel and losses in the wiring and regulator.

But if it's nice 'n shiny new, you should get somewhere around 6.5 to 7.5 amps from a "100 watt" panel.

Compare all yer panel amp outputs with how many amps yer fridge draws and you'll know if the panel set up will keep the fridge going. i.e how many sunny hours per day times how many amps you can collect in the fridge battery and how much you can store in the battery (amp/hour rating) vs how many amps the fridge pulls in a day.

On a good day, my two 80 waters that are about 8 years old, can collect me 30 to 33 amps a day. NB - that's a practical terms figure and not a theoretical one. As the sun moves but the panel is fixed you won't be collecting amps at max rate all day. It drops off very quickly if the panel isn't DIRECT and PERPENDICULAR to the sun. I have another 80 watter on the van roof that keeps my van lights going no probs.

(PS - I told you it was a "quick" way didn't I! )

HTH

Wedgtail,
Thanks for the information..
I have a better handle on checking my pannels...
Now a Question ...
Should I connect the pannels in Parallel or in series??

Cheers Nanjim
Jim

The problem if setting up in series is if you have a shadow or defect on one panel it will reduce or stop the output of all the panels. One reason I will never use an MPPT solar controller in a mobile set up is due to the panels being recommended to be setup in series. I prefer to use a PWM controller where I setup in parallel. If setting up in parallel and have a shadow or defect on one panel it will not effect the others.

low Energy Developments is a company in Victoria that I can recommend. They have a shop front and also sell online. They currently have these 200 watt panels on eBay for sale.

http://www.ebay.com.au/itm/200-Watt-12V-Solar-Panel-Mono-12V-200W-Free-Freight-Insurance-/331593538743?hash=item4d3483dcb7:g:ya4AAOSw7ThUfoCK

As others have said be wary of some panels on eBay but you will see in the specs that this panel is a good one. The open circuit voltage is 22.3 and a working voltage of 18.

Craig

Hi Ray,

Have a look at these panels selling on eBay. Look to be good value for money with free shipping.

http://www.ebay.com.au/itm/200-Watt-12V-Solar-Panel-Mono-12V-200W-Free-Freight-Insurance-/331593538743?_trksid=p2141725.m3641.l6368

Cheers

Ted

Hahaha, did you read the post before yours Ted? that's the same panel I posted .

You were too quick for me!!!!LOL

BTW You can see my setup on the URL below my signature under 'Vehicle Pics' on the bottom of this post.

Cheers

Ted

Craig wrote:The problem if setting up in series is if you have a shadow or defect on one panel it will reduce or stop the output of all the panels. Craig

Very interesting Craig, still learning here.
Just recently I've been experimenting with 120W (2x60W)panels parallel & series.
Open Circuit Output Parallel = 17V
Open Circuit Output Series = 37V
However I dragged the series panels to a position where the bottom half of both panels were shaded.
Open Circuit Output = 30V
Am unable to get a amp reading at this time, however there must be still a few amps heading for the battery?.
Hopefully Boobok will step in after Christmas and be able to verify what his series/MPPT controller reads in full/shaded positions.
If you troll the internet there are so many with conflicting results.
What is right and wrong or once again is it just personal choice?


Cheers

Not so much personal choice but the type of set up you are going to have. If you are going to mount the panels flat on your vehicle's roof and have more than one power input (solar and alternator or genny) then PWM controller is the only choice. MPPT controllers don't like multiple inputs and will only use one at a time. This means if it is on your vehicle it will not allow solar and alt. to work together so the solar input will be shut down. Unfortunately the alt is not designed to fully charge a deep cycle battery (80 - 85%). Another reason for not using the MPPT is the figures they state are a little misleading as the panels need to be following the sun to achieve what they claim. And after the initial bulk charge the MPPT acts like a PWM controller anyway.

Craig wrote: MPPT controllers don't like multiple inputs and will only use one at a time. This means if it is on your vehicle it will not allow solar and alt. to work together so the solar input will be shut down.

You wouldn't need solar while the alternator is keeping the battery 80+% so that wouldn't be a problem.
Just thinking out loud here.


Time will tell with a few experiments.

A couple of recent eBay deals;
http://groupbuy.ebay.com.au/

For all you need to know about solar panels there's a cuppla very good books by a bloke called Collyn Rivers. They're brilliant for understanding the theory and the practicals of setting up a system that will fit your needs. They show how to evaluate what power you're using, such a fridges etc and how to 'balance' that load against a solar panel system. I've had copies of two of his books for years but this one below is best for what prospectors would need:

http://www.altronics.com.au/p/b2325-solar-that-really-works-motorhome-caravan-rv-edition-book/

This is another by Rivers:


http://www.altronics.com.au/p/b2330-solar-success-book/


Good luck,

W