Supercheap solar panels

[ash_on_mtb]

Anyone had any luck runnig one of those small solar panels from super cheap, the ones worth around $100. I plan to hard wire it in to keep a top up on the battery whilst running a small fridge (6 litre) and inevitably stereo- any suggestions to maximise its efficiency?? Or have you had good/bad/no experiences with them??!!

cheers,

[-Scott-]

Got any specs, or a link?

Although the fridge may be small, if it's thermoelectric it won't be terribly efficient - a $100 solar panel may not keep up over a 24 hour period.

The other issue is output voltage. A cheap panel is unlikely to be regulated, so in full sunlight the voltage could hit 17 or 18 volts, so you run the risk of overcharging the battery and/or buggering your fridge.

Ideally, you should purchase a DC-DC converter which will output 13.8V regardless of what the panel is producing. These aren't normally cheap.

Cheers,

Scott

[ash_on_mtb]

testing the output should be a matter of finding the brightest (?!) sunshine you can and shoving a multimeter on it, would that be correct?


The fridge is one of the waeco 6 or 8 litre jobs, (which are a great drinks fridge between the seats might I add) and the panel is....

And I can't find any refernce to it, so we shall just say its crap and right the idea off as a bad joke.

Cheers for your advice

[festy]

That fridge will probably draw about 50w, so for example a 10w solar panel would need 5 hours of sunlight to put back the power used by the fridge in 1 hour.

[ash_on_mtb]

I guess the only saving grace would be that the fridge has a thermostat and in an ideal world would not be on all the time, meaning that the equation would come closer to equalling out. At any rate, some power going back into the system is more desirable than none...

But about thatovercharging system comment? Where are we at with that?? With Festy's comment, I'd be happy to run the panel, for shits and giggles if nothing else. But I'm not keen on buggering stuff!!!!

[murcod]

You need a solar panel regulator kit. They limit the voltage from the cells to a battery friendly voltage and also prevent the battery from overcharging and discharging into the cells when there is no sunlight (apparently it can happen?)

The Supercheap one may have something built in along these lines, but most likely wouldn't?

Personally I'd be shopping at Jaycar for that sort of stuff rather than Supercheap.

[festy]

Should be pretty easy to work out if the supercheap panel has an inbuilt regulator - stick the panel in *full* sunlight and measure the voltage. If it's ~13.8v it probably has one, if it's >16v it doesn't.
If you need a regulator and are handy with a soldering iron, Oatley Electronics have a simple kit to make one - http://www.oatleyelectronics.com/kits/K008B.html for $15, available via mail order.

[ash_on_mtb]

ahh, it was all a ghetto kinda arrangment when I purchased it. I was travelling in a kingswood up the east coast for 6months, and had 2 batteries to run a small fridge to keep the essentials (beer and cheese) cool. Problem was, I'd run one flat, then use jumper leads to join the 2 batteries, then wait 20mins with them connected and hope that there would be some charge in the second battery for next time.... Didn't always work out (like, ever!!) , so I *invested* in a panel from superchaep. I think it saved my ass once, so I guess it paid for itself...?! But I figure a bit more service wouldn't hurt it

[Gruntahunta]

I have 2 of these panels. I use them for keeping the batteries topped up in my quad and rideon mower when they aren't being used much. They work brilliantly for this as my mower can sit for 3 months and still have full power when i want to start it. I think this is the recommended use for those solar panels!

Cheers....................Pete!

[ash_on_mtb]

any dramas with overcharging or damage that you know of?? I'm still sitting on the fence regarding the arrangement, I've hardwired in the fridge, as well has having a UHF and stereo, all on a single battery, so its a minor concern if I leave something running etc and have only a single battery. The easiest and cheapest solution that I see is to have a solar panel continually topping up the system all the time.

Another battery- limitations include cost of battery, solenoid or redarc etc. wiring, space for battery and ancillary items

Solar panel- potential damage to battery, cheap as already have one, simple wiring, continuous charge, possible discarge at night...

Also, whilst I have your ears, whats the story with 12 v fluros that are able to be mounted to the roof (and need I mention, on a budget)? Any good ones to be had? Current draw, are they power hungry or loads better than globe? What about LED? After some light for the back of the runner as I propose to often sleep in there (not just when I'm naughty either)

cheers,