Remove the hat rack bottom?

[NicoN]

Can I remove the Panel which forms the bottom of the hat rack?

I guess, I can gain Access to the electronic compartment from there .

My intentions is to place a 12V socket in that Panel and route wires to the battery ind order to Charge the battery when in Hangar.

Of course, we have the big socket for external power in the left fuselage., but the room between the socket and the cutout is pretty small. (But I am open for ideas, of course)

[FlyBoyM20J]

On my 82J, it's possible to charge the battery using the external GPU connector provided 12V is applied to the center conductor in order to open the relay that isolates the external connector from the system.

Unfortunately, my nice AGM BatteryMinder is confused by this situation so until I spend some more time on it, on the rare occasions when I need to leave the plane on the minder, I just open up the battery access door and bypass the protection relay.

Anyone have a better plan?

[NicoN]

Hmmmm. AFAIK those battery-minders are intended to stay connected to the battery for a longer time.

Therefore i do not like the idea to leave that relay siwtched on for  weeks. AFAIK those devices Keep changing between charging and measuring the battery all the time. This may confuse the relay and the batteryminder.

As I  described, the gap between the power connector and the Skin cut-out is only 6 or 7mm.

My idea is  a very flat connector mounted on the external power connector housing. Or Mount a 12V socket in the hat rack bottom panel

[HRM]

1 hour ago, NicoN said:

Can I remove the Panel which forms the bottom of the hat rack?

I guess, I can gain Access to the electronic compartment from there .

My intentions is to place a 12V socket in that Panel and route wires to the battery ind order to Charge the battery when in Hangar.

That is exactly what I have in my E. The PO had a tap made onto the master switch relay and routed up to a Molex connector at the hatrack. When I redid the interior I put a power port in there (12 V receptacle). Works great for my Arctic Cooler.

[FlyBoyM20J]

49 minutes ago, NicoN said:

Hmmmm. AFAIK those battery-minders are intended to stay connected to the battery for a longer time.

Therefore i do not like the idea to leave that relay siwtched on for  weeks. AFAIK those devices Keep changing between charging and measuring the battery all the time. This may confuse the relay and the batteryminder.

As I  described, the gap between the power connector and the Skin cut-out is only 6 or 7mm.

My idea is  a very flat connector mounted on the external power connector housing. Or Mount a 12V socket in the hat rack bottom panel

Yes, a battery minder senses first, then applies power, goes into "anti-sulfating" mode, etc, according to its internal algorithm.

So, a battery minder can't trip the relay to then close the circuit to "see" the battery itself.

And yes, it's not a short-time recharge device, so if you want to recharge a low battery in a short time, that's largely what GPUs are for, and a standard GPU will just output 12V/24V and nicely handle the protection relay circuit on the M20J I have.

Sporty's sells an adapter for just this purpose and it ties the top 2 contacts of the M20J connector together in order to close that relay circuit (assuming you are providing power, not sensing first).  It expects only power and ground as inputs.

My use case is to keep the battery healthy if I'm away from the plane for more than a week.

So, as I said, I just remove the battery access panel and connect my battery minder directly to the AGM battery on the rare occasions when I need to use it.  I could (almost as easily) just provide 12V to the center terminal of the M20J GPU port from another source (cheap wall-wart PS would do it, it doesn't require much current to trip the relay) and then connect the batter minder to the top and bottom terminals, and then I wouldn't have to open the panel at all.  This is probably what I'll do if I find I need to do this more than a couple of times a year.

I gather this is not your intended use case, though.

Charging through a port in the hat rack sounds cool.

[NicoN]

The Picture seems to Show a socket in a case. My idea was drill a hole for the socket in the bottom  Panel, put the socket in and route a cable to the battery.

It sounds for me that your socket is switched via the master relay - correct?

I Need a cable direct to the battery to connect a battery minder.

 

[mooniac15u]

8 hours ago, NicoN said:

Can I remove the Panel which forms the bottom of the hat rack?

I guess, I can gain Access to the electronic compartment from there .

My intentions is to place a 12V socket in that Panel and route wires to the battery ind order to Charge the battery when in Hangar.

Of course, we have the big socket for external power in the left fuselage., but the room between the socket and the cutout is pretty small. (But I am open for ideas, of course)

I think I have the exact setup you  are talking about.  I used this kit:

https://www.aircraftspruce.com/catalog/elpages/audioathaik.php

The connector is mounted in the hat rack with a wire that runs through the bottom of the hat rack and connects to the battery.  The only drawback is that I have to run a power cord into the plane in order to charge so I can't lock the plane while the charger is connected.  I have a hangar so it's not really a problem.

I don't think I have any pictures but I will try to remember to take a few this weekend.

 

[HRM]

7 hours ago, NicoN said:

The Picture seems to Show a socket in a case. My idea was drill a hole for the socket in the bottom  Panel, put the socket in and route a cable to the battery.

It sounds for me that your socket is switched via the master relay - correct?

I Need a cable direct to the battery to connect a battery minder.

I would be very careful with anything wired direct to the battery. You are correct, my setup is for an in-air power port and was installed by an A&P.

When I had a battery minder, I used the cable that it came with and wired it to my battery and then ran it over to where my step comes out. After landing I could just reach up in there and find the cable and plug it in. 

You can do the same thing with the kit called out in the prior post by @mooniac15u.

[M20F-1968]

If you run the fused cord supplied with the Battery Minder that terminates in the Male/Female connector to the Battery Minder, that cord will pass between the outer skin and the metal housing of the external 3-prong plug (Cessna Type Connector).  When not using the Battery Minder and flying, the Male/Female plug can be secured inside the External 3-prong connector and the spring-loaded door closed.

John Breda

 

[takair]

There are a couple of other threads with various solutions, including pictures.  Search on Battery Minder, or variations.

[Jeev]

3 minutes ago, takair said:

There are a couple of other threads with various solutions, including pictures.  Search on Battery Minder, or variations.

I have mine routed through the external power door.  All I have to do is open the small door and plug it in, when I am flying it tucks neatly into the power receptacle and has rubber shielding around it so it doesn't short.  I will get some pics today when I am at the hangar .

[takair]

 

[larryb]

Molex connector wired directly to battery with inline fuse

[NicoN]

 That Looks fine.

The factory connector for my battery minder is a bit bigger in size, but that molex connector look good!.

i think that is the easiest way.

 

Thank you!

[larryb]

Just use aviation grade wire and hardware. Tefzel wire, nylon spiral wrap to protect it, and an in-line fuse holder like what is already around the battery. Follow standard aviation practices so it looks like it belongs.