Rebuilld Flourescent Lights

[hippieforever3]

> With respect to the fluorescent light thread, I am about to replace
the guts
> of some of mine with arrays of LED's.
>
> I am going to install the LED's in place of the existing ballast and
tubes,
> but keep the fixture and front diffuser lens, so the process should be
> reversible if it does not work out. I will report back on results
once it's
> done...

Hey Don,

I've been pretty intent on replacing the fluorescents with LEDs for
battery life and dry camping reasons.

There may however be reliability problems as someone earlier pointed
out.

LEDs are (forward biased) diodes
The power consumed in forward biased diodes goes up very substantially
with only moderate increases in voltage. The voltage drop across the
LED only increases a little but the current can more than double with a
voltage increase from 12v to 14v. This results in a doubling of the
power consumed (and heat) with this relatively small voltage increase.
This doesn't happen with conventional or fluorescent bulbs. The power
only increases a little
Depending on what type of charger, inverter set-up you have, you may
get as high as 15+volts on your 12 volt lines. Most smart chargers
regularly cycle up to 14.5v and 15+ occassionally. At "equalization"
voltage, the power dissipated by some LED assemblies could be 4-5 times
the 12v they were designed for.

Therefore if you want to get reasonable life from the LEDs you have to
do one of two things;

1. Segregate your lighting circuits so you don't get the higher
voltages that some of the more sophisticated battery charges put out.
or
2. Buy voltage tolerant LEDs.

I haven't figured out how to segregate the circuits without a LOT of
work so, I'm searching for voltage tolerant LEDs'

There are two ways LEDs can be voltage tolerant.

By putting miltiple LEDs in series the voltage tolerance of each
individual LED is improved. The voltage drop across an individual LED
is between 0.7-1.2 volts so led lamps that have 8 - 15 individual LEDs
are PROBABLY (but no assurance) reasonable voltage tolerant.
These have 12 LEDs in each bulb. I've bought a few and they are working
well so far.
http://www.buylighting.com/LED-1383-R12-...lb-2-Watt-
p/led1383-50k.htm

I've run across at least one LED module that has a voltage limiting IC
incorporated
http://www.superbrightleds.com/products/...M-xLX1/1W-
Sign_ModulesSC-NHM2.pdf
I haven't bought these yet but they should also be highly voltage
tolerant. I'm going to try them in the fluorescent fixtures behind the
defuser.

Regards,
GPSGary
1984FC35SB