G1000 206. Intermittent amp discharge on main batt. Recycle alternator and discharge goes away. Both volt meters maintain 28v constantly. New alternator all connection’s checked and rechecked. Any feedback appreciated.
G1000 amp discharge
- Thread starter Kitch
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Klaus M
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Tighten the alternator belt.
Once the belt begins to slip it will lose it's friction and stop charging.
Once the belt begins to slip it will lose it's friction and stop charging.
Couple questions:
1) Is the ammeter on the 1000 or is this the OEM meter? How many amps are indicted when discharging?
2) As to "both voltmeters" one in the 1000 and the OEM voltmeter? And no movement on either when notice the amp needle move?
Rockymountain
Line Up and Wait
If your volts stay 28, it is not your alternator. Could be an indicator issue, a big amp draw somewhere, although can’t think of anything outside of a short that could pull that many amps in a Cessna. Or some issue with how the devices pull off the battery versus the alternator. The answer may lie in the electrical schematic so you can see where the electrons flow.
Klaus M
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There's a bunch of Cessna Service Bulletins covering the late model aircraft charging issues. Don't know which ones apply to you or you've done already but find this one:
Cessna SEB-24-01
Cessna SEB-24-01
Both the Main battery and standby battery have their own V and A meter on the 1000
When I landed last night it showed an 85 amp discharge when I shut the alt off the discharge started to decrease back towards zero.
To me it almost acts like a bad ground somewhere. A&P suspects the part that does the job of a voltage regulator (I can't remember exact nomenclature)
I will check into that !
Thanks everyone for the insight !!
My bad. I missed the 28v reference. I take it this is a restart 206? Since the main voltage didn't flicker or the low volt light didn't illuminate, I'd pop the cover on the Master Box and take a look at the current sensor for the main battery. That's what drives the ammeter. And given I can't think of anything that would pull 85 amps (outside an internal battery issue) without popping a circuit breaker then return to normal you may have an issue with the sensor or its connections. What is the main battery voltage reading when you shutdown the engine?
I'll look to see if I can find a reference diagram for the master box to show the current sensor.
Good question I can't answer.... I'm sure I looked at it after shutdown, but It didnt sink in what it was reading. I was wondering about and internal problem with the battery too. They are going to test the battery in the meantime.
The extra frustrating part is we are supposed to launch on vacation Thursday bright and early and I really don't want to fly cattle class.... 1st world problems I know LOL
If they are performing a OEM capacity check it should find any internal battery issues.
If you look in the 206 service manual 24-60-00 Fig 201, Sh. 3 & 4, it will show where the ammeter current sensor is located depending on S/N or SB upgrade. The sensor is just another form of an ammeter shunt. I believe for the 1000 aircraft they are a Garmin part. Have your mechanic check the sensor connections and I believe there is also a resistance check for the sensor, but just don't recall where it is. Being a resistor they can get weak over time with heat. Good luck.
Klaus M
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While working on a T206H today it reminded me of a time when the ignition key ring had several keys on it and intermittently engaging the starter in flight. The characteristics where similar to your problem. Very high amperage draw but didn't change the voltage.
The pilot didn't figure it out until one of the times after taxiing back to parking and shutting down but the propeller kept going around.
Make sure you don't have an ignition switch that is worn out or you have more then two keys on your ignition key ring.
The pilot didn't figure it out until one of the times after taxiing back to parking and shutting down but the propeller kept going around.
Make sure you don't have an ignition switch that is worn out or you have more then two keys on your ignition key ring.
douglas393
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I think someone may have said this as well, but not sure if this is the case, but my experience with the G1000 (10 years with my T182T and now 2 years with my T206H) is that when I got erratic readings that made no sense and were not supported by secondary behavior of other sensors that should have been affected it was invariably a bad sensor or sensor wire. Erratic amperage discharge with rock stable voltage seems to suggest this. Not sure if you can swap the wire but this may be a cheap diagnostic.
Ignition switch is fairly new. Nothing extra hanging on the key.... When I was 16 and showing off my F250 I just built my grandfather said "What's all that **** hanging on the your keys ? You know boy that's gonna wear out your ignition and cause problems" From that day forward its been the key only for me LOL
Its erratic enough that I tend to think its nothing more than the panel is getting bad information from somewhere, but I paranoid enough to chase it until I find the problem or it goes away or gets sold for a newer 206
Did you ever find the cause of this or a solution? I'm having the same problem on my 2004 G100 T206.Ignition switch is fairly new. Nothing extra hanging on the key.... When I was 16 and showing off my F250 I just built my grandfather said "What's all that **** hanging on the your keys ? You know boy that's gonna wear out your ignition and cause problems" From that day forward its been the key only for me LOL
Its erratic enough that I tend to think its nothing more than the panel is getting bad information from somewhere, but I paranoid enough to chase it until I find the problem or it goes away or gets sold for a newer 206
flyingcheesehead
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With any sort of G1000 (or any other glass panel) problem, one of the first steps should be to pull the data log files and examine them for any other anomalous readings that you may have missed, or to verify your memory. You don't catch everything when you're trying to fly the airplane, and often what you find in the readings will help point you to the proper resolution of your issue.
I have been having the same issue in my 2009 172S with the G1000. Nowhere near as large of a discharge on the M ammeter. S is charging, which means the alternator is doing its job. The bus on MAIN and ESSENTIAL are remaining at 28 V. I have replaced the ACU, same part in a 172. On startup the MAIN shows a positive charge, but by time I am at run-up, or in the air and flying around, it gets as low as about -3 to -4. I have taken out the shunt in the MCU and cleaned it, along with other connectors in the MCU. I have cleaned the terminals to the main battery. Still showing a discharge. Anyone else had this continue on after taking steps to try and eliminate it?
We replaced ACU unit in our 206 and still have the issue exactly as you described. Positive on start and shows a discharge of about -3.4 by the time we takeoff. I've run out of ideas at this point.
Have you had any battery issues for the longer term, or did you find the MAIN was able to maintain its voltage for the systems? I just worry about longer XCs, and the battery all of the sudden taking a dump due to it being a real issue, and not a ghost in the machine. I did just put in a new battery, but I think it was associated with end of life. It was almost two years old, and it’s hot in the Phoenix summers.
Have you performed any basic troubleshooting like checking system voltages, voltage drops, continuity checks, etc. in addition to replacing the ACU?
All the checks performed, so far, are a couple lines up. ACU has been replaced, along with a new battery, about two weeks ago. Today, the instructor flying it just let me know the voltage is showing 27.7 V, and the main ammeter is discharging at -4 A.
So the answer is no to the basic troubleshoot. You'll find 80% of electrical issues on aircraft are wire/connection related so usually you are money ahead to have someone with the proper knowledge troubleshoot the alternator system to see if you have any discrepancies in the system first. And the fact you have replaced the battery and ACU with no joy, points to a system problem. And for reference, 2 years on a battery is not an average with a serviceable electrical system even for a G1000 aircraft or one located in AZ.
I’ve been told, that two years for a plane that sits outside is about the expected lifespan of a main battery in Phoenix. As for the basic checks, we took apart the MCU and cleaned the connections and terminals, we removed the shunt and cleaned it. Continuity checks and other terminal connections are going to be the next task.
Thank you for the assistance.