Cole Hersee External Power airframe fitting with pigtail

[Gomer Pound]

Hi, I removed the Cole Hersee housing because the spring broke, leaving the door to flap around.I tested the contacts today and found there was only intermittent continuity between the copper wire pigtail and the center "electrode." I cleaned the center electrode 360 degrees and the length of the electrod except for the tip with my Dremel and a brass brush, but this did not help much at all. The part is 48 years old, so it's not surprising. The part is $300 from piper. I was going to buy a new Cole Hersee fitting (looks the same except the two mid mounting holes are ovals instead of circular holes) and have a new copper battery cable soldered on.
Have others noted poor continuity between the center electrode and the pigtail? I assume the tip of the center electrode is some sort of Bakelite or other insulator. Am I missing something?
Clear Skies,
Gomer

[Dennis Mullins]

I don't have anything of value to offer, other than I just removed mine as well while the engine is out for overhaul. I cleaned the assembly up, painted most parts, and replaced the pin that holds the door in place. Mine has no spring, but mine is completely covered by the cowl. My neighbor's Lance has a similar plug mounted flush with the cowl.

I considered replacing the Cole Hersee part but after a brief discussion with my mechanic I decided to just put it back.

[Gomer Pound]

I had the External Power Plug (EPP) on my PA-30 B replaced by Ben at Lapeer Aviation. He did a great job, even with me watching. Piper is using a new external power socket , made by Pollak , PN 11-851 (although the part has Pollak 11-850 stamped on the flap). The PN 11-851 includes the plug and the receptacle ( you get both pieces). I will have the plug part put on the jumper cables I have to replace the old plug. The original receptacle and plug were made by Cole Hersee. You can still get the Cole Hersee parts if you like.

The External Power Plug was removed. I sent the removed plug and pigtail, the new Pollak PN 11-"850" receptacle , and the original EPP ground wire to Richard Bogert to have him make an owner produced part. He put the pigtail on the Pollak connector with the proper aviation wire and lug ,and made a replacement ground wire to replace the original ground wire (which was copper, just old).

When the new EPP was installed, I replaced the Battery relay, the Aux relay, and the diode. The Diode was from Piper, the Aux relay was from WEBCO (recieved in a Piper box) , and the Battery relay was from Peerless Electronics. The EPP now works correctly. I will use External Power to practice with the GNS480 and GMX200.

I also had the newly marketed Battery Minder harness installed since all the parts were in the same place and I have a Battery Minder, although the harness will work with others that use the same type coneector. Ben cleaned up the battery box which had some minor internal corrosion. The battery box already had the Bogert conversion and the airframe had Bogert wires. Someday I may get the Bogert Box, but there are bigger fish to fry first. I also want to wait until I get an AGM battery, so there will be no acid leaks. The Gill battery in my plane was brand new this year before I bought it, so I will wait for it to either become weak or expire...

I first became aware the External Power was not working during the pre-buy at Heritage with Cliff. His Red Baron external power supply is equipped with both a Voltmeter and an Ammeter. I observed that while the gear was being swung, the Red Baron did not deliver any amps, so I knew it could not be effectively connected to the circuit, although it was plugged into my plane. The Voltmeter read correctly. I think the connector surfaces where the receptacle and plug were just old and corroded on my plane. Another reason I removed the EPP was to replace the broken spring on the flap door.Cliff gave me a new stainless spring.

One benefit of using the new Pollak connectors is, if the spring on the door breaks, all you have to do is buy another Pollak receptacle ( $35 or less for both parts) . The receptacleand the pigtail are easily separated.The new pigtail (battery cable) is soldered to a fitting which is the center pole of the receptacle. The center pole fitting is held in by a screw. If the spring on the door breaks, it will be easy to just replace the receptacle rather than try to fix the spring. The center pole/pigtail assembly easily separates by removing the screw. Then all you do is remove the receptacle, and put in a brand new one, then screw the pigtail back on. I think this will be great for broken compared to the prior Cole Hersee soldered directly in method, even though it was perhaps, a little more solid. We can change the receptacles every 5 or 10 years now if we like, rather than every 45 years! By the way, I think my relays were fine, even at 45 years. When you read the specs on the Battery Relay, they are impressive, as in "explosion tested, tested to 50,000 feet, 100,000 duty cycles." That is one heavy duty relay. No wonder it lasts.

I also learned that Battery relays are mounted dome up. Starter relays are mounted dome down, just as I found in my Twin Comanches after I looked at them. The reason has to do with G forces wanting to pull the plunger "down." The Battery relay plunger is "down" when activated, so G forces tend to make it stay there, rather than interrupting the battery. The Starter relay is mounted "upside down" so the plunger goes "up" when activated so G forces tend to keep the starter relay "off" preventing accidental starter engagement. I had a new appreciation for the level of engineering and thought that goes into our planes. I also read Relays of this type should not be mounted on their sides, as they are not designed to operate in that position.

I bought my own Ground Power Supply at Airventure this year, a StartPac 5305 14V only model that will deliver 50 amps. I think it will be great. I saw the StartPacs on display at the Cirrus exhibit (28V) and they were humming away in the heat without a hitch as far as I could tell. I would have liked a Red Baron, but there was a significant price difference. I plan to use a "Kill A Watt" meter I already have to measure the AC amps the StartPac draws since the StartPc has neither a Voltmeter or an Ammeter to view. I won't know the DC amps, but perhaps there is a way to calculate that. I should be able to tell when it is working and properly connected, as when the master is turned on, it should show 14.2 V rather than the usual 12.8 or so from the battery (once I have the EI VA-1A Volt/ammeter connected so it comes on with the battery circuit instead of with the Avionics Master as it is now.

So, this is my birthday gift to all you out there with the External Power Plug blues (My birthday was yesterday). Once you get rid of the old receptacle (which is probably corroded anyway) and have a new receptacle and battery cable , you will be like new (or better).
Clear Skies,
Gomer