Recently, I have had numerous needs for recharging the battery on my PA-39 Twin Comanche and to eliminate the need to remove the nose cowl and replace it after charging the battery, I bought a "Plug and Jump" connector for use in "jumping off" Piper aircraft. The connector slides right into the external power receptacle a full 1.5 in. I only plan to use this for short interval charges or in an emergency for jumping off the battery and I know that the master switch should be off for insertion and removal. For a required charging of a severly depleted battery, I will remove the cowling and the battery for charging as I have done in the past. My question is: "Is it necessary to keep the master switch on when charging the battery through the plug and jump connector?".

Rule of thumb, dont charge the battery through the Piper External Power (PEP) port. The system in PA39s is designed to prevent this as the connected external power is put on the bus without turning on the battery switch enabling you to jup the aircraft in the event of needing it to start. Unregulated GPUs as are most often found at FBOs will provide the amperage necessary to start, but they will boil a battery dry in short order of left on the bus with the battery on. If you have a regulated battery charger type unit, it would be fine to connect it to the PEP and turn the battery switch on when working on the radios or something else that requires ships power without the running of an engine, but when in doubt, refer to the rule of thumb stated above. I hope this helps.
Zach

Tom,

Welcome, I see that this is your first post. I also have a 39 and have flown it for a mostly happy 42 years now. Do you know why you are having to re-charge the battery all the time? This is not normal.

Zach,

Thanks for your response. I do have a regulated battery charger which I use when I am working on my radios, my engine analyzer, digital tachometers, checking lights, etc. My question was: Must I have the master switch on while charging the battery through the use of the Piper Plug and Jump connector? Again, I want to use this connector to avoid removing the nose cowl just to provide a short 1 to 2 hour recharge of the battery. Am I correct in assuming that when you referred to the "battery swich" that you meant the "Master Switch" on the Piper panel.

Pat,

Thanks for your concern! I have had some electrical problems in the past which ultimately involved the replacement of a voltage regulator and later when that one proved to be defective, I had to install another one. Unlike you, I have only owned my PA-39 for 7.5 years. This is, however, my 5th airplane. It is also the only one that I bought used. The longest that I ever flew the same one was a 1972 Piper Seneca 1 which I kept for 18-years after flying it home from the Piper factory in Vero Beach, FL. I hope to meet you one day to learn more about the care and feeding of the PA-39. You must truly hold the record for ownership tenure of the PA-39. I hope that my response to Zach's posting illustrates why I want to bring my battery back up to a full charge after working on some of the "toys" in the panel without having to remove the nose cowl.

Tom:
In my PA30 C/R, I ran wires directly from the battery terminal posts into the baggage compartment, were they terminate in a small receptacle. I then plug the small battery tender in at this point when I want to play with the radios, etc. I have an insulated cover that plugs into the receptacle to completely isolate the system when I'm not using the charger.

Al Powers ICS 2978

PS: You and Pat have owned your airplanes for a long time, but I have been flying mine for more than 45 years, and see nothing on the market that I would induce me to trade it.

Tom,

Two annuals ago - had the nose cowl fasteners removed and now use screws. In a pinch I can get the nose on and off by myself without damaging paint by using blue tape around the edges - but not my preferred mode of operation as at 5'4", it is a challenge. My sympathies for your struggles.

Tom,
Yes, the master switch is the battery switch. Without this switch on, the battery is not connected to the bus. With the external power connected and the master switch off, all the stuff in the panel will light up (due to a power solenoid that closes anytime the PEP plug is powered), and if you have a spare battery (use to clean up power, connect the jumper cables to the battery, and the charger to the battery, then plug the cable into the plane), a battery charger, and the jumper cables, you can do whatever you want without ever putting the ships battery on the bus and risk discharge or boiling. Hope this helps.
-Zach

Zach,

Thanks for your help on this; with this posting, you not only answered my original question, but you showed me another way to work with my cockpit electronics without depleting ship's battery power!

You are welcome. Thats what were here for!
-Zach