Backyard Aquaponics
A place to discuss aquaponics

Hey guys,

Spinning in circles trying to Google this one so thought I'd see if anyone can help.

I want to install a really small solar/battery LED light setup in my glasshouse.

I'm looking at running 5050 strip emitters (circa 10m @ 30 emitters/meter = 300 emitters).

Based on 0.24W/emitter I'm at around 72W total or 6amps.

Planned usage would be a maximum of say 4 hours/day during the winter months (shorter days/less sunlight).

Can anyone help with roughly calculating a battery and panel to suit?

Cheers,
AJ

On a nominal 12V system you would be looking at something like:
A 100 Ah deep cycle battery
A 300 Watt solar panel
A 30 amp charge controller
A switch to turn your lights on
Wiring.

This would only run your lights for one day. If the sun does not recharge your battery the next day you can not yave lights again until the battery is charged.

Thanks Gene.

That's some serious battery and panels. I'm surprised!! I was thinking for a few LED strips it'd be a smallish battery and panel.

Though you are talking running the lights for a day, whereas I was only looking at max 4hrs/day.

It makes the idea kind of pointless as for what I assume will be less cost, I can just wire the glasshouse to mains and be done with it!

Back to the drawing board!

That system was designed to run your LEDs for four hours. And one time between recharges.
Off grid solar power is expensive.

Yeah, sure is expensive.

I probably totally overdid the amount of light I'd need and might be able to drop to 10% the number of emitters, and still have enough light to potter around the glasshouse after dark.

Though given your info, I'm now thinking a plan C might (A=solar, B=grid) be to just to buy 1-2 of those cheap eBay garage light/panel setups (circa $20). I had one like this (http://www.ebay.com.au/itm/Super-Bright ... Sw6DtYT1n4) once that gave a few hours of just enough light after a sunny day.

AJ

I think a lot of people are surprised to find that on most systems you spend more money on the battery than the solar panels.

If you want a battery that you can deeply discharge to say 80%, and still have it last more than a few months, you'll need a LiFePO4 battery. I'd suggest 15 or 20AH would be enough.

I don't know how big your greenhouse it, but if it was similar to my 8 X 5m, then a single efficient 10W LED floodlight should be enough.

10W X 4hours = 40Wh, say 50Wh allowing for power supply inefficiencies.

For LiFePO4 with say 95% recharge efficiency, you'd want at least 60Wh per day output from your charge controller.
Thats 5A for an hour @12V.


An unshaded 100W PV panel and adjustable voltage set point 10A MPPT charge controller should be sufficient for most of the year, and if you have a few days straight of heavy overcast in winter, just use a torch.

The bigger issue is how little power of led lighting you have. I use over 200w just for 12sq ft of grow space. Granted my led cobs have no lenses or reflectors to focus the light, but the fact remains that unless you have a tiny grow space, you will require much more light at a higher efficiency than the led strips you are using. Your 5050 strips are at most 120-130lumens per watt, look into cobs from citi. They are ridiculously cheap for tons of available power and very high efficiency. If you can afford more solar power and battery storage, look at used chevy volt batteries on car-parts.com and solar panels from sunelec.com
That'll save you tons of money and get you the best of everything for cheap. Oh and cobkits.com for the leds and reflectors(or bare to light the entire area.). Thats just from my tons of work on doing aquaponics inside my house with artificial lighting for all growing.

The OP wrote: >> have enough light to potter around the glasshouse after dark, so I'm pretty sure that brightly illuminating plants with hundreds of lumens to make them grow is not the aim here. It is just illumination to do some work at night.

Yea, i noticed that after i posted it lol. Still extending growing hours during winter time would work wonders. Just my opinion but since the money is being spent already, make the equipment at least capable of doing the amount of light that could extend grow hours. How big is the growing areas?

Hey guys,
Thanks for all the input.
Yes, just looking for work lights.
Plus given my location (Melbourne Aust), not real need to extend light hours. The glasshouse is mostly just to take the edge off the winder cold and moderate some of the summer heat (shading).
Cheers,
Aaron