12 v dimmers

Illuminating the Abyss.
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jscott83
Posts: 27
Joined: Jan 6th, 2017, 6:40 pm

12 v dimmers

Post by jscott83 »

I'd like to add a dimmer switch to my 12v led lights, found out real quick you can't use a standard house dimmer on them.
Any suggestions on a small dimmer switch reasonably priced that would work, what have other people used?
Oddmar
Posts: 98
Joined: Jan 26th, 2019, 8:57 pm

Re: 12 v dimmers

Post by Oddmar »

A standard house dimmer is rated for 110vac so even if the LED's would accept it it'd be about 10 times more resistance than 12vdc.

LED's work best at a set voltage (+/- 10%), anything less they just go out. Old-school dimmers are variable-resistors, they reduce the voltage to dim an incandescent bulb, turning the excess voltage into heat (thereby wasting any electricity that doesn't make it to the bulb).

You need a dimmer that outputs full voltage with variable pulse-width. It basically flashes the LED's faster than you can perceive, say at 100 cycles per second. Think of every individual flash as a time block...if the dimmer turns the power on during the entire block of time, the LED is at 100% brightness. If the dimmer turns on the power for 10%, then switches it off for the remaining 90% of time in that one-flash time block, the LED is really dim. Dim or bright the LED gets the full 12V it needs to run properly. And the best part, since the power is actually turned off for 90% of the time, it's only consuming 10%.

Long-winded, 'ain't I. But now you know more than you did before.

https://www.ebay.com/itm/Hot-PWM-Dimmer ... 2406171654

If you need it to be smaller, by holding it up to a bright light you can see the actual board inside is very small.

I use these LED's, they are super bright. Coat with epoxy to waterproof.
20x Super Bright LED Bulb, Pure White 12V 24-SMD Wedge Lamp
https://www.amazon.com/Bright-Trailer-M ... B0761TSXF4
jscott83
Posts: 27
Joined: Jan 6th, 2017, 6:40 pm

Re: 12 v dimmers

Post by jscott83 »

Yeah I have figured out my dimmer switch issues. And they should be working good now as soon as my new connector comes in.
I'm making a mad push to have it submerged by summer.
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