anyone using solar/LEDs

[L number Banana]

Just browsing old posts and I see I'm not the only one who would like to switch to solar and LEDs.

I've seen the LEDs in the fish mags for astronomical amounts and would rather make my own with step down transformers.

Anyone already doing this?
RV solar pads used for heaters?

[MatsP]

Using an old mobile phone charger (or some other "lump-in-the-wall-socket" transformer), along with a suitable size resistor, a few bits of wire and a bit of solder will do the job.

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Mats

[L number Banana]

Hi Mats,
I have 12V transformers for some very ugly halide bulbs. They usually run along a pierced cable and have 2 20w halide bulbs. So the step down part (resistor??) is already there. It's the kind where you can grab the two wires safely, if fact the wires with the current are part of the light's design.

I'm curious if anyone out there has a way to hook up SuperBright LEDs to them. Sort of like this company but DIY.http://www.epro-world.com/aqua-eng/Prod ... oducts.htm

No I don't care about the ability to change the look of my tank with coloured lights. Just trying to save a few bucks. Just not sure how to go about it in a way that wouldn't look like a computer chip! I was hoping someone had already done it. My 3 transformers are 3x3x4 in size but I've got tons of coated wire with it.

[MatsP]

You want a resistor to limit the current through the LED, and that's voltage/amps, so if the voltage is 12, and the rating of the LED is 10 mA, you need a 12/0.01 ohm resistor - this turns to 1200 ohms. If the rating is 20 mA, then you need a 600 ohm resistor. If you go for a too small resistor (not enough ohms), the LED will blow up. If you go for a bigger (more ohms), the LED will be less bright.

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Mats

[L number Banana]

okay, so here's the specs (stickers) for the wiring set:
input 120VAC 60 Hz 70 VA
output12 VAC 5A 60VA

the other sticker says120/12V 60hz
Max 60w~5A

What's the formula to figure out what the Ohms are?
If I read your last post okay than that would tell me what size (mA) LEDs to buy and how many I can use?

[MatsP]

A resistor is like a restriction in a pipe - it reduces the amount of current that can flow through that part. LED's do not like "free-flowing" electricity.

I'm not entirely sure that an AC power-supply is good - I'd certainly prefer a DC power-supply (just make sure you flow the current the right way through the LED's, otherwise you get only darkness). And you do not need more than about 3.5V anyways - anything more, you just don't get anything for it - it just burns up in your resistor (as the resistor for a lower voltage is smaller, it reduces the flow less, so the resistor gets less hot, which is a good thing). So, if you have (or know someone who has) a mobile phone power-supply or some such, then that's ideal.



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Mats

[L number Banana]

Okay that makes sense.
In girly non-electrician talk, I want the wavy line consistent and not dipping like AC and that could be phone chargers. Don't have one that's not in use but they're easy to find. The project is not dead yet.

And I lied, the lights are not halide but halogen, oops
What do you think of just hooking those up in a styish little boxtop? Too intense for the fish? My plants are always doing fine and can be boosted with mirrors if I need to, more worried about the fish.

[L number Banana]

The halogens are 20 w each and I can hook up 9. They're kind of like spotlights.

[MatsP]

For day-to-day lighting in the tank, I prefer fluorescent tubes. They are reasonably energy efficient, do not wear out too quickly.

Halogens are bright, but produce a fair bit of heat.

LED's are not so bright (even the bright ones), but almost all the electricity you put in is going to be light out - which is the good bit.

AC is the "wavy line" power. DC is a nice smooth line.

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Mats

[L number Banana]

AC is the "wavy line" power. DC is a nice smooth line.

Got it, had this picture in my head of AC being 60 60 60 like a wave with possible spikes and DC being like a consistent bouncing ball but only on the top of the line. Should have paid more attention in school
Do you teach electronics? You explain things very well.

My problem with flourescents is the cost of the DIY with the price of ballasts high and only one choice for 36" lamps. I could make some sort of staggered setup with 24" lamps but I'm still stuck with the ballasts. I don't like the ready made ones because I don't want the cover to fit snuggly. I want to be able to see the top of the water, blooming lilies and hand feeding.

[L number Banana]

Hey hey hey!! Just realized the RV solar kits are DC. Hmm...

Also just realized that the parking lot lights just installed here are LEDs so they can be pretty bright now. Just found some screw in ones too, cool.