Thread: Solar Panel set-up

Its OK I had a brain lapse,the watts convert to amps of charge...Should make sure the brain is working next time.
Cheers Ean

Hi Ean

I've just done a fair bit of research on the same topic.

80 Watts is recommended by all those in the know.

I just bought an 80 watt set up.

I am told that the idea is;

If you're going to prop for a while and not run your vehicle for a few days then , fit the solar panel to the vehicle battery ( that is your deep cycle second battery if you have one or just the single battery ) as soon as you can , in full sun.

This should ensure that your battery is always being topped up with more amps than what your 12 v camp lights and vehicle internal lights and fridge can draw.

It can be too late when they are already flat.

Given time they will come up in charge again but best to avoid that if possible.

Do the old electrical equation ( volts x watts = amps? )for all your lights and fridge and stuff ( fridge may already list amps drawn) and work out how many amps you will draw for the time you are stationary.
See how many amps you will use per hour for that period and deduct that form how many amp hours your battery is rated for. ( I think that's right)

Some tips for the fridge are ; keep it out of the sun if possible, buy a cover , set it on 6 degrees and not 4 to reduce run time , as you empty the fridge fill the empty space with crumpled up newspaper ( open vacant air space is more difficult to cool than the little voids made by crumpled up newspaper.

Some people run their fridge as a freezer only. When everything is frozen the thermal inertia made by the frozen stuff assists in keeping it cold.
(You freeze it at home on 240v power)

They tell me the secret to this , is to have a seperate smallish esky and two good size freezer bricks.

Open your fridge/freezer once a day in the morning to get frozen food out.

Use that and one freezer brick to keep the drinks cold.

Swap the freezer bricks as necessary.

Sorry , that turned into the Second Epistle of Paul , regarding Fridges

Pete

Thanks Pete,Did you come across anyone that stood out for price etc when you purchased yours or were they all much 4 muchness..Not to sure on how much competition there would be in Darwin so may have to source from else where.
Thanks again, Cheers Ean

Ean

Only buy monochrystalline panels.

Do a google on mochrystalline versus polychrystalline versus amourphous

Fleabay units sell for around $550 with controller , leads etc. Not sure what % efficiency they are. That is important.

I managed to get an ex demo set of e solar panels c/w controller , carry bag , leads etc for $ 350 but that was a bargain.

I'm told they normally retail for $ 1100.

When I started out looking , someone told me a rough rule is $ 10/watt therefore 80 watts x $ 10 = $ 800 plus controller and leads and carry bag if needed.

Good luck

pete

I'm no expert either, but do concur with most of the previous post. I intend sooner rather than later to go solar, but remember you will normally only get 5 to 6 hours a day of full output from the panel.

I've used solar panels on a 3 vehicles in the past. I always use Uni-Solar 64 Watt panels. They are shade tolerant & supposedly bullet proof, which basically means it is going to have to be very nasty hail to do damage to the thing. The Uni-Solar 64 Watt panels are larger than other's of the same rating, but according to the experts (sorry no links) they are equivalent to an 80 Watt panel due to their high efficiency. Unlike other panels, as the temperature increases they work better, the other panels output decreases with temperature.

You will need a regulator for your panel(s) this will ensure that you don't damage your battery(s).

If you are serious about understanding the solar systems (which in reality once you read up on them are very simple) I can't recommend the following book highly enough:

"Solar That Really Works! - Motorhome Edition" by Collyn Rivers.

He is an Australian multi disciplined engineer that actually knows what he is talking about, here is his website URL:

Cavavan and Motorhome Books by Collyn Rivers

All the best, you will absolutely love having a compressor fridge that would probably run upside down as opposed to the headaches of having to run a gas powered fridge on level ground.

Quote: Do the old electrical equation ( volts x watts = amps? )

Almost actually, Watts = volts x amps

I have a Jayco camper van which was factory fitted with one 64 watt unisolar panel and a waeco 110 litre 12 volt fridge.
other 12volt drains is internal filiment lights and a 600w inverter usually charging camera batteries and running a small DVD player for the kids.
( one light of about 20 watt is left on all night for the kids to find the toilet)
The panel is fitted flat to the roof.
Naturally one panel was not enough.
So I fitted another unisolar 64 watt......a good improvement , but I was still ending up with a flat battery after a couple of days.
The battery is a Gel 700cca size.
I have now fitted two 20 watt monocrystalline panels as well and thing is now just self sufficient on the East coast.
I have 170 watts in total.
I get about 7 to 8 amps in real terms for a few hours on a normal sort of day with about 2 amps every other time during daylight.
You can never have to much solar panel.
I know I could get more power if I angle the panels and park the camper in better locations etc............but I wanted to park and play.
I could go to more battery storage , but if you can afford it the panels are a lot less weight and at the end of the day you still need to charge them if you are set up in one spot for a long time.
Where you live and what season it is greatly affects how much solar.
Three cloudy days can stuff up the cold beer department.