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Jeff;<br>
<br>
I finally had to chime in. <br>
<br>
There are plenty of nice DC power supplies out there that will do
the trick. I have used them in the past for small sensitive
electronics that can't take high equalize voltage. you can get them
right from Digikey and elsewhere in many capacity ranges, $20 and
up.<br>
<br>
But it sounds like they haven't given you any info on how the
individual LED series strings are arranged and regulated. Do you
need one DC supply for each, or just one for the whole thing? Your
assessment is correct I think -- parallel connections are BAD with
LEDs, and the string with the most voltage will eventually fail
first, so best practice is regulate every string.<br>
<br>
And the words "void the warranty" sound extremely ominous, with
scary music playing in the background.<br>
<br>
Why not just a Morningstar SureSine inverter? You keep your
warranty, and it's just down into the amperage range that there are
some PV controllers that could switch it via a low voltage
disconnect, or you could add a small extra relay. Wouldn't have to
be big. From what I see in your post, you'll be at 120 watts from
LEDs max. The SureSine is cheap, compact, low standby draw, and if
you interrupt DC input via the controller LVD and bring it back, it
just turns right back on again with no operator resett needed. I'm
not sure about what you'd need for the timers, but I bet they are
cheaper at 120VAC than at 12VDC. There are PV controller/LVDs that
will do this too, though maybe not exactly how you need it.<br>
<br>
just food for thought anyway!<br>
-- <br>
<pre class="moz-signature" cols="72">Dan Fink
Executive Director;
Otherpower
Buckville Energy Consulting
Buckville Publications LLC
IREC / NABCEP accredited Continuing Education Providers
(970) 672-4342</pre>
<br>
<br>
On 12/16/2011 11:24 AM, Jeff Yago wrote:
<blockquote cite="mid:000301ccbc20$0ccb09b0$26611d10$@com"
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<div class="WordSection1">
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">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. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">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 $$$.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">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??<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">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?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);">Jeff Yago<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
"Calibri","sans-serif"; color: rgb(31,
73, 125);"><o:p> </o:p></span><br>
</p>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">
</pre>
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