spare battery needed for M20K

[mooneyM20K_shah]

good day,

my engine doesn’t want start with its own battery. there is barely enough power to rotate the prop just a bit. an GPU/APU does the job very well. After startup with GPU the ammeter shows a positive charging rate, droping back to normal after few minutes.

During the flight everything is normal, no indications on anomalies.

However, the engine doesn’t restart on its own battery power (tried after a 2.5h flight). a GPU is again needed for start up.

I guess the battery is dead. has anyone a better indication?

Beeing right now on vacation in Romania, with difficult access to suppliers, can anyone provide me a spare battery on short terms? see attached picture .

thanks for any feedback

Shahriar

[A64Pilot]

If there are no aircraft batteries available, I’d try to find an AGM car battery that would fit temporarily. I guess it’s either that or abandon the airplane for an extended time?

Or plan your flights around a jump start source, your a 12V airplane so that gets easier, but don’t fly IFR until you get a known good battery, because if the alternator quits, you may lose everything electrical in a short time with a bad battery.

When you do order an aircraft battery, get one that isn’t a wet cell, an AGM can’t leak.

A few of us carry jumper cables for just such a need.

[Will.iam]

I’m sorry I don’t live near you but to answer your question— if the  alternator stops charging the battery after a few minutes the battery is shot. A healthy battery that is low will take at least 30 minutes of charging before coming back to normal.  

[mooneyM20K_shah]

1 hour ago, A64Pilot said:

If there are no aircraft batteries available, I’d try to find an AGM car battery that would fit temporarily. I guess it’s either that or abandon the airplane for an extended time?

Or plan your flights around a jump start source, your a 12V airplane so that gets easier, but don’t fly IFR until you get a known good battery, because if the alternator quits, you may lose everything electrical in a short time with a bad battery.

When you do order an aircraft battery, get one that isn’t a wet cell, an AGM can’t leak.

A few of us carry jumper cables for just such a need.

that is exactly what the local maintenance offered. a car battery. however, the Mooney would not be in an airworthy condition, whatever consequences this would have in case of an incident/accident...

flying back the 1.000NM to my home airport via an airport with external power sources is an option

[mooneyM20K_shah]

1 hour ago, Will.iam said:

I’m sorry I don’t live near you but to answer your question— if the  alternator stops charging the battery after a few minutes the battery is shot. A healthy battery that is low will take at least 30 minutes of charging before coming back to normal.  

thanks for the subtle remark. indeed, the ammeter indicates a normal around-zero+ value after 2-3 minutes

[A64Pilot]

18 minutes ago, mooneyM20K_shah said:

that is exactly what the local maintenance offered. a car battery. however, the Mooney would not be in an airworthy condition, whatever consequences this would have in case of an incident/accident...

flying back the 1.000NM to my home airport via an airport with external power sources is an option

Not knowing anything about your countries regulations, I can’t comment on them.

‘In the US I believe I could get it approved as long as the replacement battery met or exceeded the Amp Hour capacity of the correct aircraft battery.

‘I’m afraid your stuck between a rock and a hard place, not that my opinion means anything but I believe safety wise, your safer with a known good car battery then a known bad aircraft battery.

‘Either way only fly a route and in weather that doesn’t require instruments and or communication if possible as you may have very little battery backup in the event of a charging malfunction, the engine will continue to run of course, but you may lose all your instrumentation to include engine instruments and fuel gauges etc. Even if you don’t lose them, the readings may become suspect when the battery voltage drops 

On edit, you’ll lose the flaps and gear too of course or at least the electric part of the gear.

Edited August 9, 2021 by A64Pilot

[smwash02]

18 minutes ago, mooneyM20K_shah said:

that is exactly what the local maintenance offered. a car battery. however, the Mooney would not be in an airworthy condition, whatever consequences this would have in case of an incident/accident...

flying back the 1.000NM to my home airport via an airport with external power sources is an option

I would rather fly back with a car battery than a dead wet cell that could boil over and trash everything. Would be an interesting conversation with your equivalent of a FSDO.

[mooneyM20K_shah]

thanks for your assistance!

i managed to find a Gill G-35 battery in Belgium via the Smets Aviation Service. they will airmail it dry to the local maintenance facility. 

luckily the maintenance here is certified for the acid refill. 

the engine will be hopefully running soon, again.

another point which i passed over: during the first of two GPU assisted engine start-ups (with only the master switch on), the HSI circuit breaker jumped out as soon as the radio switch was turned on. the annunciator pannel indicated high voltage, and the avionics was going nuts. 

I turned off the radio and master switch, and turned on the master switch again (while the engine was running on the ground). Everything was “normal” again and the avionics was apparently working. i pushed in the HSI circuit breaker again. it didn’t pop out.

during the flight, i noticed that the directional gyro of the KG102A was u/s. however the pitch gyro of the autopilot system was still working. The HSI circuit popes out again, with a subtle burnt smell. i didn’t touch the circuit breaker again. Shortly after i landed to my destination airport safely.

any thoughts about what could have happened?

during the GPU startup I did explain the 12volt nature of the system. however I didn’t see how many volts they actually applied.

[A64Pilot]

If you can find an Odyssey SBS J-16 battery, it’s a PMA battery approved for Piper Super Cubs I believe.

Its not approved for a Mooney, but if your rules are like the US, you have a better chance of a field approval with a PMA battery approved for other aircraft than a straight car battery, but I don’t know if you can find one.

Assuming of course if field approvals are even a thing there

[Aerodon]

8 minutes ago, mooneyM20K_shah said:

 

another point which i passed over: during the first of two GPU assisted engine start-ups (with only the master switch on), the HSI circuit breaker jumped out as soon as the radio switch was turned on. the annunciator pannel indicated high voltage, and the avionics was going nuts. 

I turned off the radio and master switch, and turned on the master switch again (while the engine was running on the ground). Everything was “normal” again and the avionics was apparently working. i pushed in the HSI circuit breaker again. it didn’t pop out.

during the flight, i noticed that the directional gyro of the KG102A was u/s. however the pitch gyro of the autopilot system was still working. The HSI circuit popes out again, with a subtle burnt smell. i didn’t touch the circuit breaker again. Shortly after i landed to my destination airport safely.

Sounds like they applied too many volts and toasted some avionics.....

The HSI is all electric, the Attitude Indicator is vacuum (or pressure) and electronic.   You should be able to find a good used KG102A for a few hundred dollars or even a whole HSI system for a little bit more.

Or now is the time to put the money towards a GI275

Aerodon

 

 

 

[carusoam]

Welcome aboard Shahriar!

What you are describing is what we go through with old machines…

Wire connections, relays, hours and age…

There is a capacity test for your battery… if it fails the test, replace it…. If it passes, find the next part to be checked…. Starter relays that are 50years old may have a lot of resistance in them… they get swapped out with new ones….

It really helps to have a POH for your plane… it has the most basic wiring diagram…

We have a couple of MSers in your area… let’s see if @tmo is around… he is not the closest, but let’s get the conversation started…

 

For all parts Mooney, including the battery… Lasar supplies parts world-wide…

There isn’t a good time to use a car battery for your plane… unless you are a mechanic, engineer, or crazy.  Too easy to make a mistake, or you don’t care… 

At most airports… 12V and 24V are often available on a charging cart… if you apply 24V to a 12V system… many things can let smoke out, or weld closed…

Pp thoughts only, not a Mechanic…

Best regards,

-a-

[tmo]

Unfortunately I don't have a spare aircraft battery, and it wouldn't make sense to ship one to Poland just to forward it on to Romania. If you need me to call around and ask if anyone has that particular battery in stock, I can do that, send me a PM.