Re: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

Very cool. Thanks again.

----- Original Message -----

From: Bill Watson

To: Sport_Aircraft@yahoogroups.com

Sent: Monday, February 15, 2010 7:31 PM

Subject: RE: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

 

Any normal power diode - 1N4001 or 1N4004 would be fine and is popular. Any voltage/amperage they have would do since you are running almost no current and low voltage. You cannot use a germanium? diode that would be used in a radio tuner. Yes Radio Shack should have them and they should cost a buck or two. IIRC hook them up end to end with the stripes both facing the +(red) cigarette outlet. If you lite turns on at all, then you got it right. If not, swap ends and you should be good to go. Pretty much nothing to go wrong in a harmful way.

Bill

From: Sport_Aircraft@yahoogroups.com [mailto:Sport_Aircraft@yahoogroups.com] On Behalf Of Bill Hobson
Sent: Monday, February 15, 2010 4:13 PM
To: Sport_Aircraft@yahoogroups.com
Subject: Re: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

OK - Good advice. One question - What's a diode? Seriously though, isn't there some kind of specific diode I should buy? And how many ohms, volts, amps, kilowatts or whatever should they be rated for? And you're meaning on the positive line going into the doodad right? Is this a Radio Shack item? Actually, I mis-spoke, the LED shines solid blue when the voltage is above 11.1 which would mean 12.3 BD (before diodes). Thanks for the help.

----- Original Message -----

From: Bill Watson

To: Sport_Aircraft@yahoogroups.com

Sent: Monday, February 15, 2010 2:22 PM

Subject: RE: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

 

Bill,

Consider adding 2 diodes in series with this device's power cable. Each diode makes a 0.6 volt difference. What that means to you is that with 2 diodes, the flashing blue happens at 12.4v. If you use 3, then blue flashes at 13.6v - which may be on the verge of too little distance to trouble. While your battery gives 12.6 when fully charged, if your plane is running the voltage should be >13.5v. IMHO leaving it at 11.2 is a little too far gone.

Bill Watson

bill@sportpilot.info

http://www.aa1car.com/library/battery_runs_down.htm

Battery Voltage and State of Charge:

12.68v . . . . . . . . . . 100%
12.45v . . . . . . . . . . 75%
12.24v . . . . . . . . . . 50%
12.06v . . . . . . . . . . 25%
11.89v . . . . . . . . . . 0%

(NOTE: these readings are at 80 degrees F. Battery voltage readings will drop with temperature roughly 0.01 volts for every 10 degrees F.)
(At 30 degrees F. a fully charged battery will measure about 12.588 volts, and at zero degrees F it will measure about 12.516 volts.)

From: Sport_Aircraft@yahoogroups.com [mailto:Sport_Aircraft@yahoogroups.com] On Behalf Of Bill Hobson
Sent: Monday, February 15, 2010 11:09 AM
To: Sport_Aircraft@yahoogroups.com
Subject: Re: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

Actually, I found exactly what I was looking for at an RC Helicopter web store (Google to the rescue again!). It was $6 and has an LED and an audible alarm. It's about 1" long, 3/4" wide and 1/4" thick. It has a solid blue LED if the battery is >11.3 volts, a flashing blue LED if the battery falls to between 11.2 and 10.2 volts, a flashing red LED if the battery goes below 10.2 volts and a solid RED LED and an audible alarm if the battery falls below 9.2 volts. I rigged it temporarily so it plugs into the cigarette lighter and have it attached to the panel with velcro. Now if the belt breaks, the alternator stops working or the idiot pilot forgets to turn the Alternator and Field switches on (a repeat of which in my case is very unlikely), the radio failure won't come as a sudden surprise.

----- Original Message -----

From: flybellaire2004

To: Sport_Aircraft@yahoogroups.com

Sent: Monday, February 15, 2010 9:50 AM

Subject: Light-Sport Aircraft Yahoo group Re: Alternator Warning Light

 

Hi,
No desire to step on toes.. I didn't read all the posts on this. Having an extensive background in electronics, there ARE Digital bar graph integrated circuits, which will drive a bar graph LED. They consume about 20 ma (almost non existent power wise), and the needed voltage to operate is only 5 volts. They can also be operated with a separate battery.. but why? If your A/C battery is down to 5.. then it really doesn't matter. They could also be made to illuminate an additional "front and center", brighter warning light.. or horn. The bar graph LED can be as small as 3/8" x 3/4".. so very little panel space is needed. And just as easily can be made to endure significant spikes or over-voltage conditions.

Jerry

--- In Sport_Aircraft@yahoogroups.com, "Bill" <wrhobson@...> wrote:
>
> What with our ever-increasing reliance on airborne electronic gear I'd like to install a simple (cheap) alternator warning light in my plane. Something that would maybe blink and/or produce an audible alarm when the battery discharged below a pre-set level would be ideal. Has anybody run across such an item? Thanks.
>

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