I am planning the wiring for a ground power jack. I have looked at two schematics. One is from Bob Nuckolls book, Fig. Z31A and the other from Mark Ausman's Aircraft Wiring Guide p. 51. Nuckolls' scheme seems to allow charging the main battery from the jack without turning on the master switch, and thus energizing the the whole system. The Ausman scheme does require turning on the master. Does anyone have a strong argument for one vs the other?
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Ground Power Jack
- Thread starter bob888
- Start date
1001001
Well Known Member
In my opinion the two functions should be separate. Ground power is for running electrical systems on the ground and maybe jump starting, while battery charging is a totally different beast. If you need to charge the battery, that is best done using a float charger on the battery alone.
I will have a ground power outlet that won't impress a voltage on the ship's battery without the battery master being closed.
My Piper Warrior has a ground power outlet that requires closing the master switch to apply power to the battery, and I like this way better than having no way to isolate the battery while running ground systems on external power.
I will have a ground power outlet that won't impress a voltage on the ship's battery without the battery master being closed.
My Piper Warrior has a ground power outlet that requires closing the master switch to apply power to the battery, and I like this way better than having no way to isolate the battery while running ground systems on external power.
Jesse
Well Known Member
I prefer to have the ground power jack hooked up to the battery directly, or to the battery side of the master solenoid. That way you can charge it with a charger with the master switch off, or you can run the system with the battery and charger connected by turning the master switch on.
Carl Froehlich
Well Known Member
I have a contrarian view. Assuming you are using Odyssey like batteries the need for ground power and/or a remote battery charging connection is mostly eliminated. Considering these batteries retain their charge for months, "maintenance chargers" are of little value. I also consider keeping a float charge on lead acid type batteries over extended periods to be detrimental.
There are a few occasions you may want to have the panel up and running for hours. For this I added a small door on the baggage compartment rear bulkhead as easy access to both batteries.
If for some reason you end up with flat batteries (master(s) left on or other abuse) and want to jump start, recommend you reconsider. Running a battery into the ground like this significantly degrades the battery. You may beat some life back into it and get the engine started, but you now have a very questionable amount of reserve electrical power if you loose your alternator. At ~$100 each for an Odyssey battery, just go down to your local Battery Mart and get a new one. Use the old one for your lawn tractor or such.
I replace one of the two batteries in my plane every two years - so no battery is more than four years old. This provide some assurance that my design criteria for hours of continued IFR flight after alternator failure is maintained. This procedure has served me well with two RVs over the last 13 years.
Carl
There are a few occasions you may want to have the panel up and running for hours. For this I added a small door on the baggage compartment rear bulkhead as easy access to both batteries.
If for some reason you end up with flat batteries (master(s) left on or other abuse) and want to jump start, recommend you reconsider. Running a battery into the ground like this significantly degrades the battery. You may beat some life back into it and get the engine started, but you now have a very questionable amount of reserve electrical power if you loose your alternator. At ~$100 each for an Odyssey battery, just go down to your local Battery Mart and get a new one. Use the old one for your lawn tractor or such.
I replace one of the two batteries in my plane every two years - so no battery is more than four years old. This provide some assurance that my design criteria for hours of continued IFR flight after alternator failure is maintained. This procedure has served me well with two RVs over the last 13 years.
Carl
Bill.Peyton
Well Known Member
I agree with Jesse. Mine is wired through a solenoid directly to the battery. I can charge both batteries or run everything off of the ground power in parallel with the batteries.
johngoodman
Well Known Member
I used Bob's Z31A method. Works good.
John
John
Bluelabel
Well Known Member
This is what I did. I put a male IEC plug below my access panel in the baggage bulkhead. I then made a plug adapter out of a female IEC cord for the charger. It's a 3 wire plug that feeds both batteries for charging or for running avionics on the ground. My two batteries are independent of one another, so this way I can charge them both with one simple plug. (I verified with someone who knows waaaay more than me that this was a very exceptable set up).
awmuhs
Well Known Member
external power receptacle
I like simple so I wired mine like jesse. I also mounted a piper style round external power receptacle with a spring loaded cover on the bottom of the tail cone near the battery location.
I put it there for 2 reasons. First it is accessible from outside the airplane. Second, it is nowhere near the propeller and ground crew can remove the ground power plug after I get the engine started.
I like simple so I wired mine like jesse. I also mounted a piper style round external power receptacle with a spring loaded cover on the bottom of the tail cone near the battery location.
I put it there for 2 reasons. First it is accessible from outside the airplane. Second, it is nowhere near the propeller and ground crew can remove the ground power plug after I get the engine started.
