Testing the Solar Panel-Uni Solar 64 watt

Im am not a physics professor (far from it), but I would assume its harder to keep 80litres of Air cold that it is 80 lites of food cold. So your statement of "ill leave the fridge empty to make it work harder" may not be correct. It might be more realworld to fill up some 2l milk bottles with water etc.

Apart from that im certainly interested. I wished id spent the extra $20 to get the solar regulator with the LCD readout so I could see Amp's in / Amp's out etc.

Cheers,

Glenn.

Jimbo,
When you go on your "3 day trip" why not 1/2 fill the fridge with room temp water bottles etc and run on 240v the day prior to the test, to equate to the drive to your favourite camping spot for the 3 days, and to compensate for some food contents as empty fridge is not fully realistic as we all have some stuff in them... yeh we often open the lid but there has to be some compromise.. can you open the lid a few times on Saturday and Sunday?

Also the test assumes that the vehicle was not driven during the 3 days... as the only battery charge is as supplied by the panel for the entire time.

What temperature is the fridge going to be set at?

Sounds OK to me...
I will be watching for the answer!

The test sort of sounds fair Jimbo.

But it would be fairer to load the fridge like Mainey said, it will give a more realistic result when the fridge has a chilled mass inside.
Without some sort of mass in it the thing will cycle more often than normal and give you poor figures. Chill it up first on the mains, just like we all do prior to a trip.

Regards,
Mark

Hi,

Battery will be flat saturday morning.

Anyone else want to guess when?

Cheers

Jimbo,
I'm about to go through the same stuff you have over recent weeks; trying to work out what size panel i need etc.
I've recently taken out the inefficient 3 way fridge from the camper trailer and installed a 80 litre upright Engel unit and now have 2 Exide Orbital batteries (the spiral wound jobbies). These are rated at 50ah each and I've wired them in parallel to give me 100ah. I have them constantly being charged by my new Hybralec 3 stage smart-arze charger whilst I'm here at home on the 240v; so they should be in tip top state when we head off for 4 days on the Murray over Xmas.

I'm not kidding myself, I know they won't go for 4 days; especially if it's stinking hot. So I'm gunna have to hook the Patrol up to re-charge them at various times over the weekend.

I'm leaning towards getting a 100w solar panel at present, but all these different brand names of panels and regulators just leave me wondering......WTF??? where do I start??? Well, I've sort of started by following your lead and we'll see where I end up.

Good luck with your experiment mate. (better to do it at home where there's no real damage done if things go wrong, rather than be out bush with a fridge full of hot beer).LOLOLOL

Jim.
This is good stuff, everybody should do it, my only problem is the measuring the battery voltage to determin the charge, the voltage is a very poor indication of charge, if you spend about $5 and get a battery hydrometer you will find the actual state of charge and we will all learn something from it. Thanks for your efforts. Eric.

Great idea Jimbo.
Look forward to some results - while there are lots of opinions out there - there seem to be very few people willing to put time and energy into some actual testing.
The results will also benefit yourself - it's always good to know the limits of your equipment (something my wife always comments on anyway...).

Sav.

Jimbo,

I can suggest an improvement to your testing process.

Put some beer in the fridge, (will help load it up) then when you are opening and closing it regularly on the Saturday and Sunday, you will have something to do between tasks:-))

A mate of mine has the same burning questions as you guys... what if I do this? what if I do that?

My mate does OK with his two panels and bateries for lighting, but gets into all sorts of strife whenever he's tried to keep up with the demands of his fridge.

I simply purchased a quality generator, along with a steel cable and padlock, whacked a jerrycan holder on the front of da Jayco and I run it whenever I feel I need to... rain, hail or shine (but not at night).

Stones won't break it & meat-heads can't steal it.

It runs 240v for the camper and tops up the deep cycle battery in da patrol while it runs the wayco on 12v.

Cheers Muzz

I'm in the process of looking at panells too!
Really looking forward to the real world results rather than a lot of "You Shall do it My Way" theory.
In an odd kind of way, wouldn't it be good if it was cloudy all weekend. That way the test would truly be worst case.
If the system came through on empty fridge, cloud cover, opening door etc, you'd truly know you'd designed a winner.

Geoff.

Hi Jimbo, I did this test many years ago when I started using solar power systems. When I bought my 60 litrer Trailblazer (17years ago) I was told that I would need at least 120watts of solar power to run the fridge in good weather (6-8 hrs sunlight) to maintain a battery at 75% charge capacity. Since then the best set-up I have found to keep me fully self sufficient to run the fridge in full freeze condition plus lighting at night for up to 2 weeks in fair weather conditions ( 2-3 days/week good sunlight) is 160 watts solar power (2 x 80watt BP panels) coupled to 2 x 190amp 6 volt Deep Cycle Batteries connected in series. In fact I have been camping in places for over 3 weeks at a time & never had to discharge my batteries more then 25%, which allows me to get a good life out of the batteries. This setup in good sunlight gives me a 8-9 amp charge rate which averages around 5 amps. All I need is 4-5 hours of sunlight each day. The fridge draws about 20 amps daily. I'm interested in seeing how your test goes. Cheers.

If you lay the panel flat on the ground Jimbo put it up on something just to give it a bit of ventilation.

Jimbo,
as a bit of general information for the non solar users, can you advise, if known, what your battery voltages were during the middle of the afternoon on either of the days while recieving solar power, and prior to the fridge starting, relevant to various statements of the battery only recharging to the 70% - 80% etc of capacity.
I would be expecting to see well over 13v while connected and the fridge not actually running!