G1000 standby battery charging

skidoo

skidoo

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skidoo
On my 182t with G1000, the maintenance manual says that in order to charge the standby battery, you need to remove the PFD to gain access, remove the battery, and charge it on the bench.

Just curious, how many of you have actually done this?
 
skidoo said:
On my 182t with G1000, the maintenance manual says that in order to charge the standby battery, you need to remove the PFD to gain access, remove the battery, and charge it on the bench.

Just curious, how many of you have actually done this?
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Not yet. Start the engine, and the alternator will do it. The electrical info on the MFD will tell you the charging and voltage on both batteries.

And, IIRC, any powerpack used to run the system on the ground will also do it.

The maintenance manual asks for a standby battery capacity test once a year. With the standby battery powering the PFD, set at full bright, it has to go for 55 minutes without the voltage dropping below 20.

Dan
 
Dan Thomas said:
Not yet. Start the engine, and the alternator will do it. The electrical info on the MFD will tell you the charging and voltage on both batteries.

And, IIRC, any powerpack used to run the system on the ground will also do it.
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My particular battery is low in charge. A one or two hour flight will not charge it back to full. This battery needs a 24 hour trickle charge. Looking at the wiring diagrams and confirming by operation, my powerpack will not provide charge unless the the Master Batt switch and PFD is ON. I do not desire to leave that ON for so long. Probably adds to the hobbs time. Perhaps that is why the manual says to remove the battery to charge it...

If it will recharge on the bench in 24 hours, then it may be fine. If not, I suppose it will need to be replaced...


Dan Thomas said:
The maintenance manual asks for a standby battery capacity test once a year. With the standby battery powering the PFD, set at full bright, it has to go for 55 minutes without the voltage dropping below 20.

Dan
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It just had an annual in December. I don't know if that was done or not.
 
skidoo said:
My particular battery is low in charge. A one or two hour flight will not charge it back to full. This battery needs a 24 hour trickle charge. Looking at the wiring diagrams and confirming by operation, my powerpack will not provide charge unless the the Master Batt switch and PFD is ON. I do not desire to leave that ON for so long. Probably adds to the hobbs time. Perhaps that is why the manual says to remove the battery to charge it...
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Couldn't you just hook up a charger on the airplane's battery and power up just the PFD (pull all the breakers for anything else you can't turn off)? Leave it on for 24 hours and the backup battery would be charged, no?
 
skidoo said:
My particular battery is low in charge. A one or two hour flight will not charge it back to full. This battery needs a 24 hour trickle charge.
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Something's wrong with the system. The alternator should be charging it. Perhaps the battery is shot.

Dan
 
skidoo said:
My particular battery is low in charge. A one or two hour flight will not charge it back to full. This battery needs a 24 hour trickle charge. Looking at the wiring diagrams and confirming by operation, my powerpack will not provide charge unless the the Master Batt switch and PFD is ON. I do not desire to leave that ON for so long. Probably adds to the hobbs time. Perhaps that is why the manual says to remove the battery to charge it...

If it will recharge on the bench in 24 hours, then it may be fine. If not, I suppose it will need to be replaced...




It just had an annual in December. I don't know if that was done or not.
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The Hobbs should be hooked to an oil pressure switch. Hooking it to the master is just WRONG!!!

If it's in the manual as an annual check, and it didn't get checked at annual, get yourself a mechanic who does not believe in pencil-whipping.
 
gismo said:
Couldn't you just hook up a charger on the airplane's battery and power up just the PFD (pull all the breakers for anything else you can't turn off)? Leave it on for 24 hours and the backup battery would be charged, no?
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I went out to the hangar yesterday ready to pull the panel to gain access to the battery. Before I even turn a screw, a neighbor stopped by and I told him what I was doing and how the PFD has to be ON in order to get power to the batteries. He suggested pulling the circuit breaker. That was a Duh moment!

So, I thought about it, went over the diagrams in my mind (the book was at home), and decided that may just work. So, I pulled the PFD circuit breaker, turned on the master battery switch, Armed the Standby battery switch, observed that nothing was running other than the console light, which I promptly dimmed to zero. All seemed well, so I left it overnight.

Stopped by today and the voltages were up, but not as much as I would like to see. So, another night to leave it. Now, this is with a normal float voltage and there may be some diode loss to one of them. So, I expect a slow charge.

In the mean time, I checked its history. The batteries are only 2 years old. Alternator output voltages are normal.

The main battery seems to be charging well. The Standby battery, I'm not so sure. The charging goes through a PCB assy NZ001. I have not seen the circuit diagram for that. So, I am not sure how the standby battery is being charged. I will find out eventually...

Also, I confirmed the Hobbs did not run...
 
I looked over the wiring diagrams again and found that the battery voltages are not as bad as I first thought. Looks like the main and essential bus voltages measured on the engine monitor are through shottkey diodes with about 0.5V loss. So, the batteries are that much better!

So, let me ask those who have a 182T, how typical does your standby battery hold up to the 20 second load test? Does yours (BUS E volts) always recover to 24V minimum (I assume 24.0V) after the test?
 
Once when it was VERY cold, I had the LED go out before the end of the 20 seconds. But the PFD came up, the essential buss volts were at 23.X, and after engine start I could see the standby battery charging at a fairly low current rate.

When I checked it again before the next flight several days later it was fine.

So... your standby battery should be charging during normal flight. Your standby battery should be tested annually in accordance with its service instructions. This is to ensure that the battery itself is good.

I would not launch IFR with a standby battery that didn't pass the 20-second test. VFR, I would. This is without looking at the AFM to see if the standby battery is required for day VFR. Like a Member of Congress, I reserve the right to revise and extend my remarks.
 
Thanks Tim,

I checked it again today. Did the 20 second test and it was fine. Voltages were definitely higher than before. So, this process does work. I would like to keep it on float for a long time. I just don't like the idea of having the contactor relays being continuously energized for long durations in order to do so.
 
Ken Ibold said:
If it's in the manual as an annual check, and it didn't get checked at annual, get yourself a mechanic who does not believe in pencil-whipping.
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Or actually uses the aircraft service manual to complete the annual.:yikes:
 
TMetzinger said:
I would not launch IFR with a standby battery that didn't pass the 20-second test. VFR, I would. This is without looking at the AFM to see if the standby battery is required for day VFR. Like a Member of Congress, I reserve the right to revise and extend my remarks.
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And you'd be legal.

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Great thread, I've struggled with the same issues (2005 T182T w/G1000). Another question for you guys. Can this be done with a Start Pac power supply such as the part no. 11-04537 on Spruce website (sorry can't post links yet) thru the ground power receptacle? Voltage is set at 28.5 volts to simulate the voltage when the aircraft is running (per the website). The site also say's "Not for battery charging". I guess this is several questions, such as, will this unit charge the batteries, is the wiring large enough to use the ground power receptacle? Thanks in advance.
 
Bluebird said:
Great thread, I've struggled with the same issues (2005 T182T w/G1000). Another question for you guys. Can this be done with a Start Pac power supply such as the part no. 11-04537 on Spruce website (sorry can't post links yet) thru the ground power receptacle? Voltage is set at 28.5 volts to simulate the voltage when the aircraft is running (per the website). The site also say's "Not for battery charging". I guess this is several questions, such as, will this unit charge the batteries, is the wiring large enough to use the ground power receptacle? Thanks in advance.
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If I understand the question correctly that ought to work just fine as long as you don't leave it connected for more than a few hours. It would be better if the voltage was adjusted a little lower though to prevent any overcharging of the main battery. Also, on many airplanes, external power can be applied to the main bus without turning on the master. I'm not sure if this would charge the G1000 backup battery but I think it would and with the master off the main battery cannot be overcharged. Just make sure you don't accidentally activate the starter with the master off since this can cause some unusual conditions on the main bus that the avionics might not like.
 
I also had this problem when I had a T182T if the aircraft sat for a couple of weeks, especially in the winter. This issue started when the aircraft was new so the age of the battery shouldn't have been an issue. I also always found it was fine after running the engine and/or recharging the battery.

I noticed that the 2010's now only require a 10 second test. Perhaps Cessna modified it to a lower value because of the frequency of this issue.
 
Broke down and bought a battery tender (24V) and installed the female cord to the main battery and left it sticking out of the baggage area above the battery. Now I plug it in and do what someone else mentioned. 1) pull PFD breaker 2) turn on battery switch and 3) arm the em battery. Works like a charm, now the em battery stays on past the 20 second test and the main battery is charged.
 
I don't mean to revive an old thread but since I've been looking at this battery for my 172sp I thought I'd drop a note. The standby battery on my plane (2005 172sp) uses a Enersys Hawkers Cyclon 2v 8ah cells (12 of them for 24v). Obvoiously as they age they develop internal resistance and they simply can't supply the current like they did when they were new. Luckily the Cyclon batteries are only $15 per cell (qty 12 needed). Or you can pay $800 for the whole thing.

According to the data sheets, at 8amp draw (1C rating) you can pull them down to 1.6v per cell or 19.2v... so about 20v @ 8amps is the lowest you want to go and that will basically be empty. Recharging is recommended at 1/5C or 1.6 amps with constant current charger.. Not sure what the alternator puts out but i think it'll take a while for the alternator to recharge to full..


andy
 
lots of you seem to be informed enough to answer this related question: as a back-up back-up, can I safely apply 24 volts (two 12 volt batteries in series) to the cigarette lighter (if there even is one) with the master off to power the 172 PFD? In olden days I had a Gates Rubber back-up made up of six 2 volt sealed cells to act as a back up and it worked perfectly in a Bonanza. Master off, plug in and everything lit up and the (ancient) turn and bank started spinning up, a comforting sound. I would use two-paks of the 12 volt, 7 AH batteries sold for scooters. Does anyone know what the draw would be with everything off except the PFD?

Many Thanks,

JK
 
Looks like this thread needs some updating. I own a C182T 2007 with a G1000 and I fly for CAP.

The 20 second test was revised by Cessna to 10 seconds.

http://www.capmembers.com/cap_natio...battery_preflight_check&show=news&newsID=6888

Secondly when you want to charge your main and standby batteries with an external charger, you need to turn on the Master (keep the Avionics Busses OFF) and set the Standby Battery to Arm. That will put both batteries on the charging circuit.

I'm considering replacing my Standby Battery but just saw the prices this eve. Anywheres from $2200 to $2400. Needless to say I'm headed to Sears tomorrow for a DieHard..... :)

Anyone have any stories about sourcing these batteries wholesale?
 
AlwaysBlue said:
http://www.capmembers.com/cap_natio...battery_preflight_check&show=news&newsID=6888

Secondly when you want to charge your main and standby batteries with an external charger, you need to turn on the Master (keep the Avionics Busses OFF) and set the Standby Battery to Arm. That will put both batteries on the charging circuit.

I'm considering replacing my Standby Battery but just saw the prices this eve. Anywheres from $2200 to $2400. Needless to say I'm headed to Sears tomorrow for a DieHard..... :)

Anyone have any stories about sourcing these batteries wholesale?
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Haven't seen them available anywhere but from Cessna. The original version has two 12-volt sealed lead-acid batteries taped together and wired in series. The current version (which replaces the old one) has a bunch of cylindrical sealed lead-acid cells inside a clear plastic box and wired together via a heavy circuit board.

Some owners make the mistake of leaving the standby battery switch off when flying. It doesn't get charged if it's off. The battery will sulfate over time if it isn't boosted occasionally. They will age anyway, like any other lead-acid battery, but leaving them turned off isn't saving anything.
 
skidoo said:
Thanks Tim,

I checked it again today. Did the 20 second test and it was fine. Voltages were definitely higher than before. So, this process does work. I would like to keep it on float for a long time. I just don't like the idea of having the contactor relays being continuously energized for long durations in order to do so.
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Why not wire a seperate charging loop on a seperate contactor and breaker?
 
And the standby battery can't just be 'charged on a bench'. You would need a special connector. I took a look at mine this evening. It's a special 4 pin screw collar connector. Easiest way to charge is with an external PS.
 

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Easiest way to charge is to turn the switch to Arm when you start up and leave it there for the rest of the flight. The airplane looks after it.
 
AlwaysBlue said:
Agreed. I was speaking of methods when the engine is not running.
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What I'm not getting is why the battery sent coming up to full charge after a 2 hr flight, and why t doesn't stay there. What is the drain?:dunno:
 
AlwaysBlue said:
And the standby battery can't just be 'charged on a bench'. You would need a special connector. I took a look at mine this evening. It's a special 4 pin screw collar connector. Easiest way to charge is with an external PS.
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That looks a lot like an Amp CPC (Circular Plastic Connector) series connector. Yes they are a commercial connector. Yes they make different types and sizes of contacts. Yes they are found in aircraft.

https://www.google.com/search?q=amp...ved=0CAYQ_AUoAWoVChMIh4iPhNOcyQIVijYmCh2E-gYm
 
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Henning said:
What I'm not getting is why the battery sent coming up to full charge after a 2 hr flight, and why t doesn't stay there. What is the drain?:dunno:
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If a battery does not have much capacity left then it won't last long even after being fully charged. Cessna specifies a 55 minute test to determine if the battery has enough capacity for 'backup' fiights such as Night VFR and IFR. I would start by running this test before looking for a 'drain' as it is easy to do.
 
AlwaysBlue said:
If a battery does not have much capacity left then it won't last long even after being fully charged. Cessna specifies a 55 minute test to determine if the battery has enough capacity for 'backup' fiights such as Night VFR and IFR. I would start by running this test before looking for a 'drain' as it is easy to do.
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I agree, a battery at this stage that was bad I would expect to fail the load test he already performed, but yes, that is his next test.
 
Took the Standby Batt out and disassembled. There was some bad corrosion/sulphation on terminals. In fact one terminal was so corroded it broke off fairly easily. Such corrosion increases resistance in the charging circuit so that you can't put in current on the charge cycle or pull it out when you need it. Voltage levels won't tell you this info. Good time for a rebuild.
 

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The battery part no. is 0850-0004
 

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I understand this standby battery to be an ordinarily three year type item. My cost to replace last month was $1065 plus one hr of labor.
 
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