[RE-wrenches] DC power for LED lighting

[Jeff Yago]

I have a local sign company that asked is to provide a solar lighting system
for a double sided sign they were building for a large retirement community
entrance.  We have provided many solar lighting systems just like this over
the years and sent them several examples.  All our systems have been
turn-key in that we provided the 12 VDC ground mounted LED flood lights with
the separately pole mounted solar module(S) and battery/controller box.   We
"assumed" when we told them our system includes the LED lights that they
understood that we were providing the lighting.  

 

Unfortunately, when we arrived on the site to install the solar system, they
said they did not need our LED lights, they wanted us to power the LED
lights inside the sign.  We opened up the signs and found two 120 VAC
electronic LED power supplies.  Each was clearly labeled as providing a
maximum of 5 amps at 12 VDC output, and each powered a separate string of
about 150 tiny plastic "blocks" and each block contained 2 small LED lamps.
We immediately advised the client that the solar  system was designed to
power our two  12 VDC flood lights and we would have to totally tear out
what we had just installed and go to a much larger system that included an
inverter, larger array, 120 VAC timing device, and replace the 2 conductor
DC underground wiring  with 3-conductor AC wire and all  this would really
increase $$$.

 

I said as an alternative, why can't we just cut out the two electronic120
VAC input  LED drivers since we are providing well regulated 12 VDC power
direct from the GEL battery.   He checked with their LED lamp supplier and
they said they strongly disagree and will void warranty.  Since we are
talking about almost 300 total LED devices my client is afraid to give us
the OK, even though we did run them overnight and everything worked just
fine.   As I recall, an LED needs something in the circuit to limit the amp
current, not the voltage flowing through it,  or it will just get brighter
and brighter and then fail.  However, I thought almost all strings of
separate LED lights already had some kind of regulator built into each light
block otherwise those near the end of the string would be less bright than
those near the power source.    Is this correct??

 

Finally, if strings of LEDs require some kind of voltage or current
regulator, I can't believe they all have to run on 120 VAC as indicated by
this LED manufacturer who offers no alternative.    Any LED experts out
there that can point me to some type of DC-to-DC converter or current
regulator that can replace these 120VAC LED drivers?

 

Thanks,

 

Jeff Yago

 

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