solar panels and inverters

Why use a 240V inverter ? I use a DC to DC 12V Computer inverter from Jay Car electronics to run & charge my computer of 12V.

Hi Outback

I'll let the experts answer re your solar panels. However i think you are ambitous about the amount of charge you will get out of an average day. Will you only be using power for the fridge? What about lights, water pump, running your inverter? I have also discovered that solar panels under-perform in hot weather. When in the north this has been an issue for us.

We are now powered by 4 130 w panels and have 4 110 a/h batteries. This is working for us.

I would choose pure sine wave inverter for your computer. My inverter recently let me down, and i got good advice from ExplorOz members. I now run it from the 12 volt on a power supply. Then a cheaper modified sine wave inverter would be ok for recharging batteries.

Motherhen

You are going to be sadly disappointed by the performance of your solar
system. Suggest you need to do some research.
You could start here.
(http://www.exploroz.com/Vehicle/Electrics/Solar.aspx)

A realistic output of your panel would be 7.5 amps and depending where and when you are 6 hours could be a good estimate. Lets say about 50 amp hours per day.

Have a look at the peak sun hours chart here.
(http://www.solar4power.com/map8-global-solar-power.html)

If you only want to power a computer it's more efficient to get a 12 volt power supply such as this one from Jaycar.
(http://jaycar.com.au/productView.asp?ID=MP3472&keywords=mp3472&form=KEYWORD)

I have a cf50 Waeco and running as a fridge ( 0 deg) I would use 30 to 40 Ah a day in hot conditions i.e. 30 deg during the day and 16 deg at night. On freezer (-15 deg) I have used up to 64 Ah a day in the same conditions. In places where it is cooler the current draw is much less. When conditions are bad I have had to manage my fridge so that I use all the available power from the solar panels during the day (e.g. -20) and turn the fridge up a notch during the night. (-10)

As Lex M states, you will get about 50 Ah out of the panels on a good day. The hotter it is the worse it gets. I have just added another 80 watt panel to give myself 240 watts which I think will be enough for my requirements. I like to keep my batteries on float as much as possible to prolong their life.

I use a 300 watt inverter (not pure sine wave) and it works okay but the laptop power supply gets a lot hotter than when I use 240 v at home so probably not a good idea.

Regards,
Bob

Recently returned from "the Trip" - My setup of 80 watt panel to 85 aH battery powering ONLY the Waeco CF50 was OK until we got 3 days up in the high 30's ..
Then I had to power the battery from the 140 watt panels on the camper and all was well ...
Since returning I have switched panels and batteries so that the Waeco now has a 100 aH and 140 watt panel - This should be OK for most remote usage ..

I ran my laptop from a 12 volt car charger from the camper and various chargers for the Camera's and phones and never ran out of power .

I have also put a 20 Amp controller in the Jeep so that I can connect both panels
if necessary ...

Mandrake - now preparing for his next adventure..

These figures are seriously confusing.

"fridge that draws 2.9 amps per hr"
- do you mean the instantaneous draw ?- that's measured in amps
- do you mean the average consumption ? - that's in amps - or amphours per hour if you want to waste words.

"105 w batteries"
- do you mean 105 amphours ?

Sure, people can assume what you mean, but don't expect reliable answers.

Thanks everyone for your feedback. yes my initial info was confusing but your repiles and places to go for inofrmation have really helped my understanding of the situation.

Its a great forum where you can get some immediate feedback and a real reality check.

cheers

As an everyday working example, I've a 200 Watt solar system, with a fridge that draws 10 Amps ( 2.8 ah ) and my Solar system maintains 2 x 100+ ah AGM DC batteries 100% charged after about 11Am on an average day.
(some less expensive panels are not capable of this)

The sole point of a Solar system is to charge the storage battery system, remembering the fridge will only be running ~40% of the time, in the fridge's off time the solar system will be putting ALL it's charge into the battery system.

As a guide, when the fridge is running, Solar should be supplying the full charge of the fridge under good conditions.

The storage battery system will be fully charged each night and then it only has to run the fridge at night and it will again be fully charged next morning.

If you get an inverter, get one that is suitable for the job you intend it to do.
I would (and do) use a PSW inverter, as it can be used for everything, as it's the same waveform as the 240v in your home, cheaper inverters generally are not PSW and do not give the same clean 240v power.
Remember the inverter uses battery power to run, the bigger the capacity the more it uses, so get an inverter that is sized appropriate to the work it is likely to do and turn off the inverter when not in use.
I use a 4 plug power board running off the inverter and can recharge 4 items at the same time.

Maîneÿ . . .