Kevin Trombley via EV wrote:
I am assembling a few Batt-Bridges.
In the description it specifies D2 & D3 are "red high-efficiency LED" & D1 is
just a green LED.
...in the written description down below it says: "Use an ordinary low brightness green"
& "the red LED's should be high brightness types -- the brighter the better, so you can
see them even in daylight.
All say about the same thing (I think) but, it's NOT CRYSTAL CLEAR for the lay
person (your average DIY guy or gal)
Yes, they are all saying the same thing. There are no good definitions
for LED efficiency and brightness, so I had to use generic terms.
...for the record, which LED's are the "right" ones for building a Batt-Bridge?
Electrically, what matters is the voltage drop across the diodes. The
*color* (or more precisely, the wavelength in nanometers) of an LED
largely determines this. The green LED should be about 565nm and drop
about 2.1v at 10ma. The red LEDs should be about 635nm and have drop of
about 1.8v at 10mA.
Visually, the LEDs can be whatever color and brightness you want, as
long as the voltage drops are about right. Since the green LED is on all
the time (it just tells you the Batt-Bridge has power), you don't want
it to be annoyingly bright. The red LEDs indicate trouble, so you want
them to be bright enough to notice, even on a sunny day.
...what is the "proper" size/gauge wire to be used on Batt-Bridges?
(It will carry pack voltage but, only ~10 - 20ma)
The current is low, so just about any size wire will work. Choose it for
mechanical strength and insulation quality rather than wire size.
Be sure the insulation on the wire is good enough. You're connecting
these wire to your high voltage pack! Good wire will have its voltage
rating printed on it, or in its data sheets.
Also, put the resistors at the battery terminal end of the wire. That
way, if there is a short in the wire, the resistor will safely limit the
I do sell the Batt-Bridge
<http://www.sunrise-ev.com/LeesEVs.htm#battbridge> But in fact, I sell
only a couple a year. Most people build it themselves. So in the spirit
of experimentation, it's up to them to figure out what LEDs work for
their particular needs. :-)
Whether we or our politicians know it or not, Nature is party to all
our deals and decisions, and she has more votes, a longer memory,
and a sterner sense of justice than we do. -- Wendell Berry
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)