M20J Auxiliary Power Adapter

[bennergh]

I have a 1977 M20J (12 volt electrical system) that has an Auxiliary power adapter installed over the battery, which has a connector on the left rear fuselage. I'm looking for an economical way to power up my panel to play with my Aspen/Garmin 430W while parked.

I found this unit on the 'Sportys' site: http://sportys.com/PilotShop/product/11988 (see image attachment)

It seems like I should be able to use an automotive 12 volt power adapter with this unit for an economical way of powering my panel without the engine running. It may even be useful as a battery charger in a pinch as well?

Does anyone have any experience in this arena?

[carusoam]

Bennergh

This will allow you to charge your battery with a typical 12v charger.  It is a three wire system that automatically keeps things from being wired with reverse polarity.   

In some electrical systems, you may find that while charging the battery this way is fine, a contactor opens the circuit to rest of the system protecting electronics / avionics.   Leaves battery, and starter the only things alive in the circuit.

Check your wiring diagram.

-a-

[Piloto]

I have the same GPU adapter on mine (14V) and it works very well for either charging the battery or checking the avionics. If you have a panel voltmeter verify the voltage is at least 13V when the GPU is connected to insure there is no battery discharge. I use an automotive 12v charger as a GPU and it works very well. Normally you have to set it to 10 amps or higher to get a good charging voltage.  

José

[bennergh]

Thanks Guys!

I found this on http://www.skygeek.com for $754 (pretty pricey!) but it's 14/28 volts. I'm feeling partial to the automotive charger that you specified (less $$), that would require a 10 amp power factor.

Do you guys feel like the automotive charger will power my avionics as well as keep the battery charged simultaneously?

Thanks again!

~ Greg

[carusoam]

Greg,

You only want to exercise the Aspen / Garmin....

You can always turn off the other devices.  Everything can be individually turned off except the turn coordinator.

If for some reason you want to turn off the TC, it can be unplugged behind the panel....

In the event you run the battery down, you can still recharge it.  Keep an eye on the voltage.  The electronics are protected, but you still would not want them to see low voltage.

If you completely destroy the battery, let it run down and freeze in the winter....  You can still by a few new batteries compared to the cost of that very nice 12 /24v charging device.

Check with your FBO, they may let you borrow or rent these devices also.  Mine has a starting cart (8 batteries and a charger) that I have used in the past.

-a-

[Piloto]

You can get a good automotive charger at Sears that will crank your plane for less than $200

José

[Bob]

Does anyone know what parts are needed and labor required to add a charging port to a Mooney?  Some Mooney's have a small door in the leftside avionics axcess panel on the left side of the fuselage.  Now that cold weather is near, I am thinking about adding one to simplify charging.  Any help is greatly appreciated!

[Vref]

Quote: Piloto

You can get a good automotive charger at Sears that will crank your plane for less than $200

José

[bennergh]

Cool! Excellent information ... thank you everyone!

~ Greg

[Magnum]

I bought a car/truck charger, 12/24 Volts in Germany for approx. US$ 130. I cut the wires and installed an adapter like the one in Vrefs post (approx. US$ 50). Works great for playing with the avionics or charging the battery. I used it today to swing the gear.

[DaV8or]

Quote: Bob

Does anyone know what parts are needed and labor required to add a charging port to a Mooney?  Some Mooney's have a small door in the leftside avionics axcess panel on the left side of the fuselage.  Now that cold weather is near, I am thinking about adding one to simplify charging.  Any help is greatly appreciated!

[Dale]

Has anyone actually used the yellow 3 pin charging device found at sportys to actually jump start their Mooney?  Also, can this little plug and jump 3 pin device be hooked up to one of those portable battery jumper units used to start dead batteries on cars. Since the portable battery unit is starting a 12 volt car battery it would seem like it would work on Mooneys with the 12-14 volt systems.  If anyone knows, please let me know. I am thinking about buying the yellow 3 pin charging device found at sportys and getting a 12 volt electrical charger to keep the battery charged while in the hangar and then purchase an inexpensive portable battery jumper unit to take with me in the plane should the plane battery go dead while at some out of the way airport.  Any thoughts would be appreciated.  Thanks.

[bennergh]

I bought one of these units (below) from Sportys and have used it extensively, especially getting to know my avionics:

http://sportys.com/PilotShop/product/9663

I have a 1977 model M20J with a 12 Volt buss, but Sportys has a 24 volt version as well. It works nicely and I have no complaints.

I've killed my battery before by leaving my master switch on and couldn't revive it. In speaking with other pilots and my local AP, there's typically no reviving a gel cell once they have gone down to the lower thresholds of power. You might be able to try a trickle charge, but even that can become a hopeless scenario from what I understand.

Early on I bought one of the yellow paddle connectors is hopes of building my own PS but decided to just purchase the above. I feel as though given the proper ampacity (25 Amps), an off the shelf automotive charger will do the trick just fine. Just remember to tie the smallest connector in the paddle to B+ and you should be good to go!

~ Greg

[Magnum]

Quote: Dale

Has anyone actually used the yellow 3 pin charging device found at sportys to actually jump start their Mooney?  Also, can this little plug and jump 3 pin device be hooked up to one of those portable battery jumper units used to start dead batteries on cars. Since the portable battery unit is starting a 12 volt car battery it would seem like it would work on Mooneys with the 12-14 volt systems.  If anyone knows, please let me know. I am thinking about buying the yellow 3 pin charging device found at sportys and getting a 12 volt electrical charger to keep the battery charged while in the hangar and then purchase an inexpensive portable battery jumper unit to take with me in the plane should the plane battery go dead while at some out of the way airport.  Any thoughts would be appreciated.  Thanks.

[RJBrown]

I have the yellow plug pictured. I have used it on 12 and 24 volt Mooneys. It works great. Expensive for what you get though.  With it any battery charger can be hooked to it for use. Auto specific chargers cost much less for the same thing. I believe the aircraft specific items we are offered often are re labeled car stuff. 24 volt is common for truck specific equipment and still wont cost what "airplane" stuff does. In a pinch a 24 volt plane can be jumped/charged with a 12 volt charger in series with you car battery.

[Bennett]

The Sporty's unit is fine.  I carry one in my baggage compartment in a small soft case with a digital voltmeter/ohm-meter (and leads) and a few tools such as a combination wire stripper/crimper, assorted crimps, and a couple feet of stranded wire - all just for emergencies. (or where some switch was left on and the battery was driained down.) Come on, we have all done that at least once. 

[Awqward]

I was using my GPU yesterday to play with my avionics when I noticed the Volts had dropped back to 16-17v...(I have a 24/28v system)...and I thought I could smell burning rubber....so I disconnected the GPU thinking maybe it was fried...the volts did not move....the GPU checks out ok so I think I have fried the Aux power relay or solenoid....does anyone know where I can buy these parts? I found the part numbers in the Illustrated parts catalog but no joy in finding anywhere they can be bought...

[carusoam]

Did you try aircraft spruce? They are good for parts support for items like that.

When you apply voltage to the external plug, it should clunk into the closed position.

You can hear it accross the hanger.

Use caution when attaching it to high tech voltage supplies.

(1) The high tech deals sense voltage first, then apply voltage. When the battery is fully charged, the charger drops off. Followed by the solenoid opening and your battery discharges while you use it.

(2) the system works well for protecting against reverse polarization, but it adds a little pain.

Sound familiar, or am I alone on this?

Best regards,

-a-