Solar Power Wattage

G'day Shawn, I have been through a similar exercise recently of determining power consumption and the means of regenerating it. If you message me with your web address I will send you a copy of an "excel" spreadsheet that I used to begin to solve the problem.
Regards, Murray

Shawn,

You will find lots of useful advice at campertrailers. You might also look for the manula on campertrailer/caravan electrics by Collyn Rivers. 50W is plenty for running just lights.

Peter

Shawn,

The first thing is to work out how much power you expect to consume. The arithmetic for this exercise is not difficult but a bit hard to explain on this forum.
You then need to get a "practical" specification for the actual power the solar panel(s) in question will produce Although rated at 50, 60 or 70 watt they apparently, in practice, do not produce at 100% of their respective ratings.
To be self sufficient for say three days you need to be able to replace the current you use in any one day by the solar panel/regulator plus a bit for losses.
There is a good book on the subject wriiten by Collyn Rivers. I think it's called "Solar that Really Works"
www.motorhomeandcaravanbooks.com.au.

Hope this helps as a guide
10 watts = .5amps
20 =1.1 Size BP solar panel .424mm x 502mm
40 =2.3
60 =3.5 1110mm x 502mm
80 =4.55
125 =7.1 1510mm x 674mm

work out what amps each unit drawers this is usually in the manual or on the plug of the unit you are running and this will give you a good idea of what you need

COST BIAS boating supplies in all states

10 watt $164 20 watt $264 40 watt $389

60 watt $569 80 watt $729 125 watt $1089

PLUS you will need a regulator if there is a chance of over charging you battery
approx cost $80.00 at same supplier
hope this is of use to you

Hi Shawn,

I have used a 20 watt panel for 3 years to charge up a 27 amp hour battery set up to run lights of up to 3 amp current draw of a night. Longest stay on battery power was 10 days with no problems.

If all you are running are lights and you are in an van (not a 25 foot motor home where you might need plenty og light to find your way from one end to the other) then 50 watt should be ample to replace your nightly usage.

Wolud strongly suggest you wire in a good ammeter calinbrated up to 5 amps so you can read the draw. You will need to go to Jaycar or similar to get one. The ammeters sold in auto store do not give a fine enough read out.

That way you can monitor your current draw at night.

Also you should have a voltmeter installed to tell battery voltage. If the van does not come with one fitted, then a visit to Jaycar will see you fixed.

Lastly buy a good battery charger of around 2-4 amp output so you can put the rig on charge before you leave home. Better to leave home with a fully charged battery than not. If you go out with obe only 80% say then you will have problems as the panel may not bring your battery up enough after the first night.

Saw that just last week. Brand new off road rig. Flat battery after first day. Camper and wife, experienced too, hadn't charged it up before leaving home. Wasn't me, but fellow camper had a generator so charged him up enough so they could stay the week provided they didn't run any lights at night.!!

And, yes, Solar panels do not put out the rated amperage except under ideal laboratory conditions. So, most people over solar rather than under solar.

Having said that, lights only, up to 3 amps draw, 50 watts should be ok.

Have fun

PS I assume you will also carry an emergency gas light. I use a small Gaz model with disposable cartridges. Takes up not much more space than a roll of toilet paper but when you need it!! Like Toilet paper, can't do without it.!!!!.

Cheers

Magnus

Shawn, A 50 amp panel should do lights & music. As for charging on the move I used a second isolator from main battery to a 50 amp anderson plug cost $100 whereas a redarc to do 3 battries cost $600. If you are in Sydney I can give you a top auto elec to do it for you.

Thanks to all who have donated info.
I have spent all afternoon (at work) looking at the suggested sites and have found answers to most of my questions, so thanks very much to all

cheers
Shawn