I am newer pilot flying a 2008 g1000 gfc700. Pre flight and en route battery indications are normal, however, when I land and taxi back for some practice takeoffs/landings, battery starts to drain and goes red x even at higher rpms. When i shut down and power back up indications return to normal. Any thoughts?
Cessna 172 g1000 battery issue
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Dan Thomas
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Usual issue here is possibly the same as most other alternator-equipped airplanes: worn field brushes in the alternator, or brushes contaminated by grease from the rear bearing. How many hours on this airplane?
Dan
ajstoner21
Cleared for Takeoff
I have no idea what to suggest, besides look in the G1000 flight manual supplement and see what it says about a problem like that.
skidoo
Line Up and Wait
What do you consider higher rpms?
skidoo
Line Up and Wait
Do you have a bunch of lights or other loads ON during landing that are not ON during re-start?
ajstoner21
Cleared for Takeoff
What is the current draw on the different busses at full power? landing?
skidoo
Line Up and Wait
Sorry, I can't help with such short, incomplete responses to questions. It takes too much effort to try and interpret what you intended to say and creates a lot of assumptions which are easily mis-interpreted.
Sorry-trying to do this on blackberry. I consider high rpm's to be full power. I took off and did a pattern and battery didn't charge. Only items on when I am landing are flaps and strobes, no other electrical draw.
OzPilot
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The g1000's i have flown usually always show the alternator slightly charging the battery even at low taxi RPM.
I would get the alternator checked out
skidoo
Line Up and Wait
I guess I just don't understand when you your be using full power after landing. On mine, I have seen this after landing and power was cut back to idle, i.e. below 750 rpm. Once I increase the rpm to above 900, all goes back to normal. Keep in mind that alternator's typically have significantly reduce output capability at idle rpms. So, any additional load will have a more significant effect.
So, if you go to full power, i.e. > 2400 rpm, or even less power, say 1200 rpms, and it still shows discharge and the voltage is less than 13V or 26V, certainly have the alternator system checked. I don't recall if the 172 has a 12V or 24V system. Mine is a 182 with a 24V system.
Dan Thomas
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The 172 has been a 24-volt airplane since the '80s. Charging voltage is 28 and a bit.
Dan
I taxied at low rpms (8-900), and that is when main battery started to discharge. I taxied back to runway and went around the pattern again and the battery continued negative charge. I landed, main battery went red x, and I taxied and shut down. I restarted engine after couple minutes and it was charging again.
skidoo
Line Up and Wait
I'm confused. Your battery was discharging with a red X, you then took off with the discharging battery and it remained that way throughout the pattern? And, then it went red X after landing again? When did it go from the battery discharge red x to normal between the first landing to the next landing?
Dan Thomas
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Shutting the system down can allow failing components to cool. He said he shut the engine down for a couple of minutes, restarted, and it began charging again.
Either the system is overhcharging and the overvolt sensor circuit in the regulator is shutting it off, or the field brushes in the alternator are gummed up and quit conducting when they got hot. In any case, it needs looking at before that battery gets sulfated or the airplane gets a long way from home and causes considerable inconvenience.
Dan
After landing on a 40 minute xcountry flight, i wanted to do another landing for practice. As I taxiied back to active runway, battery began discharging. I took off at full power, did a pattern, and when I landed, battery was still discharging at -13.5 indicator, and went red x before I parked. I flew back home today and all was normal. Will have it checked out. Thx.
Last weekend I had exactly the same failure: I started the engine experiencing the same problem as you describe. Nothing worked untill I shut everything down and performed the starting sequency again. I performed two flights of an hour and four hours afterwards with no problems. I have the same year aircraft you have, with 350hours on the engine.
I would be interested to see if anybody knows what is all about.
I would be interested to see if anybody knows what is all about.
iflyatiger
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What might be happening is that by shutting down and then restarting the plane is that you are accomplishing the same thing as recycling the field side of the alternator. If your master switch is a split type switch next time this happens try turning off the alt side only of the master switch, leave it off for 5-10 seconds and turn it back on ( you can do this while it is running ). If this bring the alternator back to charging then your problem is with something triggering the alternator control unit to go off line.
There could be many causes for this type of problem ranging from loose or high impedance wiring, power or ground in the alternator circuit, bad or sparking brushes in the alternator
( this is my guess )
If it were me and I needed to cycle the alt side every once in a while I would definitely consider flying it home in vfr conditions.
Good luck and please let us know the results of this test.
Disclaimer: I am not familiar with your exact plane.. Please do a little research first to make sure that cycling the alt side is an valid function in your aircraft. It should be in the standard operators manual.
There could be many causes for this type of problem ranging from loose or high impedance wiring, power or ground in the alternator circuit, bad or sparking brushes in the alternator
( this is my guess )
If it were me and I needed to cycle the alt side every once in a while I would definitely consider flying it home in vfr conditions.
Good luck and please let us know the results of this test.
Disclaimer: I am not familiar with your exact plane.. Please do a little research first to make sure that cycling the alt side is an valid function in your aircraft. It should be in the standard operators manual.
VFR ir IFR?