240w Solar Panel - Is this a good deal?

[threedogs]

hi, just checked that link. think you can do better.their 100 watt job only puts 2.7 approx. back into your battery, try OZ PLAZA, even Jaycar have cheap panels now I'd be looking at 80 watt ones as you don't really get much more the larger you go. just wasting money. I light my backyard with a 20 watt panel and 18AH motor bike size battery

[Sir Roofy]

Hi AB, a lot of weight for the output, I use a BP 80 watt job that throws 4.5 amps back into the battery and a third of the weight. never had a flat AUX battery yet. I'm looking at getting a folding 80 watt job. Only time they wont work is when its raining. Save your money down size to even 120 watt folding but you only get 5.5 amps back. Thats probably why the 80 watt is so popular. When camping we now use LED flood lights and plenty of them,, Cd/radio on all the time plus keeping the beer cool. Work out how many amps you use but for me 80 watts is heaps.

thats all we use 80watt had it for a couple of years now

[threedogs]

Hi Macca those panel just don't have the frame, great for a boat or caravan roof, would like to know how the edges are sealed. your right probably come at a price, seeing people pay $30k plus for a trailer with a tent on top. AB's on the right track just needs to shop around a bit more.

[the evil twin]

Hi ET, got the reply back and you were correct mate...

Max current is 20 amp though, not sure what's going on with this unit.

Yeah, thought as much... not worth a pinch of poo to ya mate

The posts above are correct in that you will get more charging current out of a smaller wattage 12 Volt (nominal) panel. You can pick them easily as the max voltage in the specs will be about 19 Volts

I run 2 x 50 watters and that is heaps for two Engel 40's and a motza of LED lighting plus general Lappy use

[threedogs]

Seems bigger does not mean better, well as far as solar panels are concerned

[AB]

Great information gents, thank you!!

Learned a heap from this thread...

[Cuppa]

Just seen this thread. You have been well advised AB. In addition I'd add that I reckon 120w folding panels (ie. 2 x 60w) are about as big as you'd want to go. Anything bigger than this just becomes too cumbersome to move around, load, unload etc on a regular basis, as well as heavy. I have 120w 'folders', but reckon 100w folders are probably the optimum size to get.

Some people advocate more smaller panels than fewer large ones on the basis of damage risk. Break a large one & you lose a lot more than if you damage a smaller one. They are fairly tough things, but can be broken.

The regulators that generally come on these cheap panels will work, but are generally very cheap junk. Also it is best that the regulator is mounted as close to the batteries as possible, not stuck on the back of the panels. I reckon it's best to replace the supplied regulators with something a bit better. I know a number of people who have used one of these regs happily for many years. Certainly not the best available but a a good honest regulator with an LCD readout to tell you what's going on with your batteries. Most of my experience has been with a Steca PR series reg & a Morningstar Tristar. The Morningstar is top notch, but I probably wouldn't buy another Steca.

Also replacing the cables supplied with the cheap panels is a must if you want to get all that the panels can supply into your batteries. The supplied cables are just too skinny which will make voltage drop a problem. For my 300w of folding panels I have made a 10 meter lead (allows camping under shade with panels out in the sun) from 6 B&S twin cable (13.5mm2 conductor). This has way more current carrying capacity than what the panels will produce, but it is preventing voltage drop which calls for the heavy cable. Aim for a max of 3% or less voltage drop. Shorter cables can be lighter.

For best conductivity you need good connections. I use Anderson plugs. Beware of non genuine lookalikes on eBay. There are stories of the copies having greater resistance after a period of use. The genuine Anderson plugs have a silver coating on their terminals and are reported to be more reliable in the long term.

If using several fold up panels Anderson now sell an item called an Anderson Power Block. This is 4 interconnected Anderson plugs in a tough aluminium shell, allowing for 3 panels to be connected plus the cable back to the batteries

Hope this helps anyone thinking of buying some solar.

Regards
Cuppa. ♨

[AB]

Helps a lot, good read thanks Cuppa!