Ammeter issue?

[Guest]

My ammeter looks like this in flight. Looks like discharge, but I am showing constant 13.8 volts on voltmeter and I’ve flown enough flights with it like that so that if it were discharging, I would probably have a dead battery by now…. Is there a way to adjust it?

[MB65E]

Yes most Voltage regulators will have an adjustment screw. 14.0-14.2 will be fine. 
-Matt

[PT20J]

Does the needle show zero when the master is off? If not, some meters have a zero adjustment screw on the movement. You’d have to take the meter out of the cluster to check. 

[Guest]

I thought that 13.8 was ok on the volts. I was worried about the amps. Should I turn up the voltage?

[PT20J]

14v to 14.2v is optimum, but you shouldn’t be getting a discharge at 13.8v. It’s always a good idea to check the instrumentation accuracy before adjusting anything. 

[Guest]

I'm a dummy.  I never thought to check what the gauge looks like with the master off.  I will have to wait until next week when I can get back to the airplane to check.  Thanks for the input.  Do you guys think I should worry about fine tuning the voltmeter up to 14.0 or should I just leave it at 13.8 as close enough?

[ArtVandelay]

I'm a dummy.  I never thought to check what the gauge looks like with the master off.  I will have to wait until next week when I can get back to the airplane to check.  Thanks for the input.  Do you guys think I should worry about fine tuning the voltmeter up to 14.0 or should I just leave it at 13.8 as close enough?

What matters is the voltage at the battery, I would measure this directly with a digital voltmeter just to verify there’s not a voltage drop from a bad connection or solenoid somewhere.

[Fly Boomer]

42 minutes ago, Kerrville said:

Do you guys think I should worry about fine tuning the voltmeter up to 14.0 or should I just leave it at 13.8 as close enough?

That voltmeter is not a precision instrument, and no amount of calibration will make it so.  Use a precision instrument and make sure your regulator is about 14.1 volts.  That's for a Concorde -- not sure about others.

[Yetti]

Mine used to do that.   battery lasted the standard amount of time.

[Guest]

Finally got back to the airplane.  The ammeter looks the same when the power is off.  It shows the same slight discharge.  When I switched on the master it moved a bit left.  If I can't adjust it, I will just consider the current position to be the new zero.

[Ragsf15e]

2 hours ago, Kerrville said:

Finally got back to the airplane.  The ammeter looks the same when the power is off.  It shows the same slight discharge.  When I switched on the master it moved a bit left.  If I can't adjust it, I will just consider the current position to be the new zero.

A cigar plug voltmeter/usb combo is comforting if you’re ever concerned.  I got an amazon one and it shows current V on the bus.  It stays pretty steady at 14.0 for me.

Heres the thing about the ammeter in the Mooney, the way it’s designed is only to show the charge/discharge from the battery.  So it should normally show slightly positive charge even if you have everything turned on (assuming alternator is on).  If the alternator dies, then it will show significant discharge and it will depend on what’s turned on.  An easier number to interpret is the bus voltage which will be 14ish with the alternator on and 12.3ish with only battery online.

Edited May 18 by Ragsf15e

[Guest]

My oat gauge is a combination of a bunch of things and I usually leave it on voltage. That seems to be a lot more useful to me than temperature most of the time. It shows 13.8 which sounds like it might be a little low. I got a new zephtronics voltage regulator installed about 6 months ago…

[MikeOH]

FWIW, my voltmeter (built into the Insight G3) reads 13.8 - 13.9 Volts consistently for the last 6 years. Never had an issue; I'm not inclined to 'bump it up' for no other reason.