D i y high intensity lighting

stevieduk · Apr 10, 2012

Hi everybody, before Christmas I wrote about a idea i had for low running cost high intensity lighting for a coral tank using 12 volt xenon bulbs.
Well the lights are up and running and work well. I ended up using car driving lights , into which i put H.I.D Xenon bulbs, which run at 8000 k and give a nice blue / white light. I am using a 75 amp/ hr car battery which will run the light for two hrs, and can be recharged at night using cheap rate elctricity.
I know this is only 2 hrs of light, but it gets switched on around midday to imitate the midday sun and giv the tank a boost, and its a damd site cheaper than metalhalide to run

Poseidon · Apr 10, 2012

Have you done the math on energy usage?

What wattage does you charger draw, for how many hours in order to fully charge that battery?

I am all for making light cheaply, but usually it ends up being the same cost or even MORE then some of the more readily available options, that may have higher initial costs, for lower energy bills.

stevieduk · Apr 11, 2012

yes , the maths work out at half the price. Example--Battery charger takes 100 watts so would take 1 KW in 10 hours which would cost at night rate Â£ 0-07p. Night rate electric is on for 7 hrs only,between midnight and 7 am, which is long enough to recharge the battery , so costs about Â£0-05p to recharge the battery, to get 2 hrs light from it.
A small 250 watt metal-halide lamp would run for 4 hrs to use 1 K W of electric. As it would be on in the daytime for the equivalent 2hs, it would be using daytime rate electric, which at the moment is Â£0-21p per KW. So to run a lamp for 2 hrs would cost about Â£0-11p
So as you can see its half the cost , and no doubt with a lamp , you would be tempted to have it on a lot more , where as when the battery runs down you have no choice but to switch it off . Its all about useing electric when its cheap rather than running costs of the equipment.
Or I suppose you could switch the day round and have your lights on at night when you are in bed and have the tank in darkness in the daytime.
I have a friend who packed in keeping his marine tank because he was running halides and was starting to get electricity bills for over Â£1000 per month !

Troylee · Apr 11, 2012

You could run LEDs "12v" off that battery for 8 hours on the same charge or close to it.. Just something to think about...

Reef Breeders · Apr 11, 2012

I would not use a battery for leds, the current must be constant, not so much the voltage.

mcarroll · Apr 16, 2012

Just a technicality :nerd:, but isn't xenon one variety of halide? Unless mistaken (well possible) these are at least very close to being halide lights that run on 12v instead of 120/240v. I don't think it's possible for them to be much more efficient than a similarly rated "regular" halide due to this.

This is not to diminish the coolness of this project, however!

First, it uses car parts to light a tank - that's just cool. Also, this does give the demonstrated benefit of using off-hours power regardless of when your lights are on during the day. In my area I would not benefit from that, but many other areas would. These lights may also have a lower setup cost and/or lower bulb replacement costs than traditional halides since (if you believe what they teachin business school) there should be pretty massive economies of scale from the automotive industry as compared with the halide-using population within the aquarium community.

Having said that, and recently switched from halide to LED myself, I might be inclined to use this "time shifting" technology in that direction.

-Matt

P.S. If you wanted to, wouldn't it be simple to extend your Xenon's to 4 hours (full day for coral, more or less) by merely adding a second battery to your setup? (Not to say you should want to.

)