LED from China Update

rpwillia · Apr 23, 2011

Did you set up for Side Mount or Back Pin Mount?

joker460 said:
One last thing. I traced out the PCB board and attached the schematic diagram of the above LED.

Pretty rocking thread!

sea_casper · Jun 10, 2011

LED Brightness varies with current

joker460 said:
One last thing. I traced out the PCB board and attached the schematic
diagram of the above LED.

The device between the Rectifier Diodes and the LED Ballast Resistors is a Linear Voltage Regulator.

The most efficient LED lights use a switching voltage step-up regulator and have all the diodes in series with a single resistor or sometimes an active current regulation is built into the switcher voltages of 36 to 60 volts are typical depending on how many diodes are in the string, basically they regulate the current to a fixed value and the voltage will be what it is for the characteristics of the LED's. LED brightness is a function of current. The voltage across each diode will vary more between devices than it will vary on one device over a range of current and thus brightness. The voltage is non-linear and will vary with temperature. The ballast resistors coupled with a voltage regulator can stabilize brightness, but each string in parallel will vary.

luken7 · Sep 5, 2011

I was all set to try this but they're no longer available on ebay. Seller has pulled them. They're on my watch list now in case they come back.

Forrest15112 · Sep 6, 2011

I like the idea of a single power supply regulator at the dc panel. That way, you could just plug the LED board in and go. A regulator added to each fixture seems like a lot of work and would have to be done to your spares. It would be more practical to create a single higher power regulator better protected from noise and ripple especially if running on an alternator. It's just LED's so it really isn't a big deal unless the light is pulsing or wavering. How long have you used these LED's and have they been reliable? I've heard some pretty bad things regarding cheap LED's.

alexco38 · Sep 6, 2011

If the centralized regulator failed, all lights go off. Not a good idea.

sea_casper · Sep 6, 2011

Single Power Supply Impractical.

Forrest15112 said:
I like the idea of a single power supply regulator at the dc panel. That way, you could just plug the LED board in and go. A regulator added to each fixture seems like a lot of work and would have to be done to your spares. It would be more practical to create a single higher power regulator better protected from noise and ripple especially if running on an alternator. It's just LED's so it really isn't a big deal unless the light is pulsing or wavering. How long have you used these LED's and have they been reliable? I've heard some pretty bad things regarding cheap LED's.

A single power supply will not work, LED Lamps are composed of a series of individual LED's, The power supply built in to a LED lamp regulates the current through the string, the voltage across the string will vary only slightly for large changes in current, it will also vary at a fixed current as the ambient temperature varies, it will also vary at a fixed current from LED lamp to LED lamp.

Maine Sail · Nov 8, 2011

Eric M said:
I have been playing around with these sorts of LED lights also - what is the purpose of the voltage regulator? I have installed two without the regulator and they appear to be working fine. I have 2 more samples of LED pannels in route as I type. The first two I am playing with are not quite as bright as the stand bulbs they are replacing.