Using Solar Panels to Recharge Power Pack

[Rodstar (Rod)]

I am looking for some input on this topic.

In the event that I am camping somewhere where this is no power available, I would like a set-up where I can leave the power pack recharging during the day with the help of solar panels. I recall seeing HOughy with that sort of set-up at SPSP a couple of years ago.

I have found the following link, www.solarguru.com.au/index.php?cPath=5, which has reasonably priced panels, but I am very unsure about how they might connect up to my power pack (12V), or whether they would have enough power collecting grunt to give me sufficient recharge night after night.

Any ideas / experience? Thanks for any help you can give.

[g__day (Matthew)]

I would guess you'd want to generate about 2 move volts than the battery supplies (check your charging transformers' spec - is it 14V with 3 amps to charge a 12 v battery?) and run it through some electronics to prevent over charge or actual drain if the voltage and ampage of the cells isn't within range of what the transformer delivers.

Maybe ask Jaycar is their a converter kit.

[Starkler (Geoff)]

You would probably want a panel rating of 2x the current drain of your scope setup. My scope running dew heaters flat out and argo navis uses about 2A.

A 30W module at $344 gives 30/12= 2.5A. A 40W module is $415.

Probably cheaper just to bring along enough battery power to last your trip if its just for a star party lasting a few days.
I have a box containing 2x17Ah gel cells which gives me an estimated 17hours usage for under $100.

[Astrod00d]

For 12 years I've used an 84W panel mounted on top of the 4WD for extended camping trips with great success. Soon I'll be using it to top up my imaging rig batteries. On average the panel will produce it's rated output for around 8 hours per day, a little more at midday and a little less in the morning and afternoon when the sun is not directly overhead.
Solar panels work best when pointed directly towards the sun. If the panel is movable, you can shift it to track the sun and get much better performance throughout the day.

A large panel will need a regulator to prevent overcharging the battery. A smaller panel, say a 2A panel for a 20AH battery will only need a simple blocking diode if you're charging the battery from a discharged state (cyclic charge). If you plan to leave the panel and battery connected for a month between observing sessions (float charge) then a regulator is advisable.

Cheers,

Rob

[xstream (John)]

Rod you should should find this doc. of some use. Solar can be an expensive exercise, fitting our van out with solar to be self sufficient was well over $4,000.

[gmbfilter (Geoff)]

Rod
Pro Disk Entertainment, Howarth St Wyong.
Have lots of solar goodies on display
I've spent heaps with them before Energy Aust. come to the rescue

[seeker372011 (Narayan)]

Rod
I was in Jaycar the other day and they seem to have a whole range of stuff-worth a butchers maybe?

[IanL]

Try this company. We use thier products for powering remote web camera's at mine sites and construction sites.
http://www.rfi.com.au/solar/solar-home.html
PS
If you tell them what you want to power they will pick the correct pannel for you.
You will need to work out what you want to power and what the currant and amps are so you can get the battery packs for the solar to charge it

Ian

[MrB (Simon)]

"currant and amps"

Same same.

[acropolite (Phil)]

Originally Posted by Geoff

A 30W module at $344 gives 30/12= 2.5A. A 40W module is $415

Not quite so. Solar panels are rated at their peak output, usually delivered around 18volts for standard 36 Cell panels. Therefore an 80 Watt panel will deliver around 80/18 i.e. 4.5 amps. At normal charging voltages (12-14 volts) the current output is much the same but multiply 12x4.5 and you don't get 80W.

On an average sunny summers day you can count on roughly 7 peak hours, in the case above around 31.5 amp hours available from your 80Watt panel, around half that figure in winter (at least here in Tas).

You can increase this by manual adjustments during the day to track the sun, ensuring the panel stays roughly perpendicular to the sun's rays.

FWIW, current output can be higher for short periods (I've measured peaks of 30% above normal) on cloudy days when direct sunlight falls on the panel and reflected light from clouds reinforces the sun's energy.

[xstream (John)]

To reinforce what Phil is saying, here is a link of a map to:-

Solar Hours V Solar Amps from Solar Panels for Battery Charging