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pvalovich

Well Known Member
I'm about to transfer my -8A from the workshop to the hanger. The "big stuff" is done and I am involved in finishing all the deferred tasks. One thing I had thought about was installing a ground power plug near the step. Seemed like a no brainer until I realized there was going to be a pretty substantial weight penalty involved (plug, wire, relay, etc) - and I'd have to run a fat wire through the firewall and cockpit from my forward-mounted battery.

I realize this might be one of those "Get 5 pilots in a room and you have at least 18 opinions" things. But is the utility of an external power plug worth the weight penalty? Or is a charge-the-battery-through-the-oil door process good enough?
 
Use a "powerlet"

I installed one, on the interior, with a 15a fuse direct to the battery w/ 14g wire. I put it on the aft face of the F806 above the armrest, along with the rear seat headset sockets. I used a Powerlet, it is common on motorcycles for heated vests and other accessories, and it is a way-better quality connector than a cigarette lighter plug/receptacle. The female bulkhead mount receptacle has a nice cover.

I put a male powerlet plug on my battery charger* and on the external power cable for the auxiliary Garmin 196 that I provide the backseater. I also made a short pigtail that adapts from the Powerlet to a cigarette lighter receptacle, so that if someone else needs to plug something in, I can do it.

* There is a dilemma here: sometimes you want to put power in, sometimes you want to take power out. So, should you put a male or female plug in the airplane? I opted for the female receptacle. But this does mean that a battery charger that plugs into it has a male plug - not recommended or customary practice. Fortunately, the Powerlet plug is pretty well designed and I don't think you could short the contacts with anything flat like a sheet of metal or a screwdriver or wrench. You would have to work at it to short the contacts on the plug.
 
I am actually doing this tonight when I get home. Since I am going with a IO 360 I am installing my battery in the aft location. I think this spot is a lot harder to get too charge a battery so I am installing a cigarette litter socket in the F-807a bulkhead with a fused 14 gage wire directly to the battery, shouldn't be to much weight and it will double as a power source. Then I will use a male cigarette liter adapted to my battery charger to charge. The only downfall I can see is it will always be hot, even with the master being in the off position.
 
Matt,

Would be useful to incorporate a fusible link (or a fuse) in this so that if it gets shorted nothing gets cooked.

greg
 
The "need" for a good, reliable ground power connection used to depend mostly on a pilot's experience in having to jump start their (previous) plane(s) in cold weather when the battery went dead....I had done this enough that i swore I would always have a jump-start capability where I didn't have to drag big cables and clamps through little holes into the airplane, so I put in a single-pole Piper-type jack in my -8 (on the belly, right next to the aft-mounted battery, to save cable weight).

The advent of all-electric panels (EFIS) has given another very good reason to have an external power plug - there is usually a lot of test and checkout that needs to be done, including software updates and configuration. it is truly wonderful to be able to do this in an unhurried fashion, knowing that as long as the "shore power" holds out, you can take you time and do it right. This also helps when learning to use the systems. This, of course, does not take the kind of amperage that a jump start requires, so smaller connectors can be used. The argument then goes, if I am going to have an external power system, whey not jump in all the way and make it adequate for jump starts?

The penalty is a couple of pounds of weight, and every pilot needs to determine their need for an external start system. I can tell you, it sure is nice when I am visiting up north in the winter to plug into a start cart and see the prop blades go around nice and fast - as opposed to watching them laboriously try and pop over TDC with an internal start.

Just a few things that go into the decision! I am currently debating what is going to go in to our -3...eventually, we're going to be living in a cooler climate than what we have here in Houston....

Paul
 
Paul,

Unlikely that the climate here will be so cool that starting is an issue! I have a sump heater and cylinder band heaters and never have had an issue with starting. I suppose that one could also put a small heater on the battery as well. I also have a float charger built into the tailcone and have the battery on float all the time to keep it topped up. Weight penalty is less than a pound.

greg
 
I put one in my -10....

...because when you're away from home and it goes down to 25 degrees at night, it may just save the battery after sitting outside all night.

I have the Reiff oil pan heater but on trips, there often isn't an available extension cord and plug.

Best,
 
Proof positive

David Paule said:
My Cessna 180 has one, and I've never needed it in the 24 years I've owned the plane.
Click to expand...

Your experience is proof positive that having a ground power recepticle installed is a good idea. We all know that the odds are you would have needed one if you didn't have it.
 
AN2552-3A

I'm planning to install a standard 3-prong ground power receptacle (AN2552-3A). It will be mounted on the forward side of the firewall near the battery and relays to minimize the length of the wiring run. The receptacle will be accessible via a small door in the side of the cowl. This is a similar arrangement to many production aircraft.

Purpose for having it (as others have already mentioned):
1. Recharging the battery
2. Prolonged ground operation of avionics without draining the battery
3. Jump start from a standard power cart

Note: When I bought the AN2552-3A receptacle I was actually surprised at how heavy it is. I didn't weigh it, but it feels like about a pound. Still, in this case I chose to take the weight penalty for the added utility.
 
My installation sounds similar to Roee's. I installed it for the same reasons. The power supply I'm using works very well for extended avionics testing and configuration. Here are some pics:

IMG_4968.jpg


IMG_4969.jpg


IMG_4970.jpg


IMG_4971.jpg
 
I installed a big honkin' round ground power plug in the bottom or our -9A, and we've Never used it in over three years, and I don't plan on it anytime soon. I'm not going to install one on the -8 project.
 
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