Low Voltage annunciator

[Rookie]

Does anyone know where the annunciator reads the voltage from?

Mine keeps blinking but I know I have 13.6 while flying.

 

 

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[DVA]

Hi Rookie, assuming for a moment that your alternator and the regulator is operating correctly and that you do not indeed have a low voltage condition, it's not uncommon to see the lamps illuminate errantly due to one of two leaky diodes on the circuit board in the annunciation panel. I have a schematic somewhere, and it's not a difficult field repair. There are a few places that will work in those only oem boxes, maybe someone else can chime in.

[carusoam]

Somebody has posted the wiring diagrams for the anunciator panel before...

Not sure which years are covered.  

The drawing combined with DVA's advice is a pretty strong way to have an instrument tech test for things that aren't wotking properly...

Isn't there and adjustment for that?

anything over 13v is a sign that the alternator is working...(?)

A fully charged battery doesn't usually show 13+v while not being charged...(?)

the details of the anunciator panel are kept in the MM.

PP thoughts only...

Best regards,

-a-

[kortopates]

Does anyone know where the annunciator reads the voltage from?

Mine keeps blinking but I know I have 13.6 while flying.

 

 

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13.6 v is a bit low, your battery wants 14.0v for maximum longevity.

 

 

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[Rookie]

I need to look in POH but the light should not come on over 12 volts. I though I read that.

[kortopates]

I need to look in POH but the light should not come on over 12 volts. I though I read that.

I'd have to look it up too, but you're off by at least a volt - I would expect lower 13v range. You're no longer charging when it drops to 13v.


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[laytonl]

Schematic is in the service manual.  Lee

[ArtVandelay]

Schematic is in the service manual.  Lee

Only for serial 3154 and later, earlier Js you have to refer to a drawing which I don't have in the electronic copy of the service manual. Nice troubleshooting section, anyone actually have the drawings? The supplement schematics are only the plane's wiring.

[laytonl]

Didn't know that.  My J is s/n 3258.  Lee

[Rookie]

I flew it again Monday and the light did not come on. 

[Guest Mike261]

I see the light at idle only, taxiing and such. I find  the hotter the ambient is the higher the RPM has to be to extinguish the light. on the hottest days 1180 will extinguish the light.

I can go from september to june and never see it lit once, but i see it during the dog days of summer. (98 J)

Mike

[EricJ]

A real easy way to monitor the system voltage is with one of these things plugged into the cigar lighter:

https://www.amazon.com/Car-Charger-Smartphone-Temperature-Fahrenheit/dp/B00SWGWILI/ref=sr_1_1?ie=UTF8&qid=1501025200&sr=8-1&keywords=usb+charger+voltage+meter

The display cycles between input voltage, output current (the current at 5V to whatever USB devices are plugged into it), and the ambient temperature.   I've been flying with one of these powering all the USB doo-dads for a while and it's really handy to peek at the display and see what the system voltage is up to.

 

[Rookie]

17 hours ago, EricJ said:

A real easy way to monitor the system voltage is with one of these things plugged into the cigar lighter:

https://www.amazon.com/Car-Charger-Smartphone-Temperature-Fahrenheit/dp/B00SWGWILI/ref=sr_1_1?ie=UTF8&qid=1501025200&sr=8-1&keywords=usb+charger+voltage+meter

The display cycles between input voltage, output current (the current at 5V to whatever USB devices are plugged into it), and the ambient temperature.   I've been flying with one of these powering all the USB doo-dads for a while and it's really handy to peek at the display and see what the system voltage is up to.

 

I actually have one just like that.

That's how I knew my alt. was charging and the battery voltage was ok.

[carusoam]

That is good for both 12 and 24V... 

-a-

[trevttu76]

I know this is an old thread, but got me thinking I see similar issues.  
Where is the voltage regulator box in a J model?  I have a 1978 to be exact.  I can't recall seeing it under the panel...

[N201MKTurbo]

4 minutes ago, trevttu76 said:

I know this is an old thread, but got me thinking I see similar issues.  
Where is the voltage regulator box in a J model?  I have a 1978 to be exact.  I can't recall seeing it under the panel...

it is bolted to the firewall on the copilots side about 6 inches down from the glare shield.

 

[ArtVandelay]

it is bolted to the firewall on the copilots side about 6 inches down from the glare shield.
 

Mine (78) is more on the side by the vent on copilot’s side. FWIW

[PT20J]

My 78 had a rather large OECO regulator mounted on the firewall up high under the glare shield. My 94 has a Mooney regulator which is much smaller and located at the base of the copilot's panel just to the right of the center console on top of a small tray.

[kortopates]

My 78 had a rather large OECO regulator mounted on the firewall up high under the glare shield. My 94 has a Mooney regulator which is much smaller and located at the base of the copilot's panel just to the right of the center console on top of a small tray.

And that is the difference between the 14v and subsequent 28v installations.


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[trevttu76]

On 2/13/2023 at 3:13 PM, N201MKTurbo said:

it is bolted to the firewall on the copilots side about 6 inches down from the glare shield.

 

Is this the VR?  This is mounted along a plate perpendicular to the firewall close to the glare shield (co-pilot side).    If so, does anyone recognize the model and know if there is an adjustment to raise the voltage a bit.??  My voltage is consistent, but mid 13's, would like to get it closer to 14V for my Concord RG.

[OR75]

this looks like a Lamar  Electrodelta VR415 regulator