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Any places I shouldn't connect my battery charger?


peevee

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Our battery has been moved to the back, so the battery box is empty and I can't just connect directly to the terminals. 

 

Is there any reason I can't just use something like the battery side of the gpu power socket relay or one of the other +12 connections there at the box and ground the charger to the airframe? 

 

I can't imagine there would be an issue, but you never know. 

Edited by peevee
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Are you using a battery minder?

In this case the hardware is mounted near the battery.  A cable with a small plug is brought out to a convenient spot.

The convenient spot at the back can be an O2 door or the ground power door.

i have seen pictures of a ground power door added to the Access panel on the side.  If you need to add one?

Best regards,

-a-

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Yes, battery minder. 

 

The question is where to connect the harness. Directly to the battery isn't an option. 

 

There are a few places near the original battery box that are +12 continuously, so I'm asking if there is a reason I'm not aware of that makes it a bad idea to connect there. 

Edited by peevee
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Peevee, can you explain why the battery direct connection is not an option?  I have a fused link disconnect for my battery charger to connect on the rear mounted battery in my K.  If I couldn't connect it to the battery then I would trace the positive and negative leads out of the box and connect it to the first junction found on each.

 

Ron

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You can put it anywhere on the permanent +12V side of the battery.. so yes, the battery side of the GPU socket is fine.  Battery side of the master relay is another common location.  It is general practice to make the run to the battery as short as practical, but the current is low < 1.5A.. so voltage drop over larger runs is minimal. 

The requirement for permanent battery tender connections in aircraft is that the harness be fused.  

http://www.batteryminders.com/batteryminder-model-bm-aik2-airframe-interface-kit-for-use-with-faa-certified-aircrafts/

You *could* just use the GPU socket.. if you had a separate way to bootstrap the relay (9V battery).

The original battery minder 28252-AA did it that way... the more recent ones had a 28v "startup" mode to trigger the relay.  The standard chargers want to sense the battery before they provide current as a protection circuit. 

I can't find the old 28252-AA manual.. but it implied there was another version of the A2GPU plug that included a 9v battery  to bootstrap the GPU relay:

http://www.batteryminders.com/content/manuals/28252-AA.pdf page 14 note.  page 15 mentions a A2GPU-2 plug.. 

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11 minutes ago, Marcopolo said:

Peevee, can you explain why the battery direct connection is not an option?  I have a fused link disconnect for my battery charger to connect on the rear mounted battery in my K.  If I couldn't connect it to the battery then I would trace the positive and negative leads out of the box and connect it to the first junction found on each.

 

Ron

Because we have a rocket and both batteries are in the tail cone. 6 or so feet aft of the equipment bay door. I don't want a run that long or to climb back there to do it. 

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11 minutes ago, PaulM said:

You can put it anywhere on the permanent +12V side of the battery.. so yes, the battery side of the GPU socket is fine.  Battery side of the master relay is another common location.  It is general practice to make the run to the battery as short as practical, but the current is low < 1.5A.. so voltage drop over larger runs is minimal. 

The requirement for permanent battery tender connections in aircraft is that the harness be fused.  

http://www.batteryminders.com/batteryminder-model-bm-aik2-airframe-interface-kit-for-use-with-faa-certified-aircrafts/

You *could* just use the GPU socket.. if you had a separate way to bootstrap the relay (9V battery).

The original battery minder 28252-AA did it that way... the more recent ones had a 28v "startup" mode to trigger the relay.  The standard chargers want to sense the battery before they provide current as a protection circuit. 

I can't find the old 28252-AA manual.. but it implied there was another version of the A2GPU plug that included a 9v battery  to bootstrap the GPU relay:

http://www.batteryminders.com/content/manuals/28252-AA.pdf page 14 note.  page 15 mentions a A2GPU-2 plug.. 

Thanks! I've never had much luck with using the gpu port, as long as there's nothing to worry about ill proceed. 

It's fused but I need to extend it about a foot, I'll do that beyond the fuse. 

Edited by peevee
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9 minutes ago, peevee said:

Because we have a rocket and both batteries are in the tail cone. 6 or so feet aft of the equipment bay door. I don't want a run that long or to climb back there to do it. 

We don't quite understand this... if you are attaching it to the GPU port (in the old front battery compartment).. then the run to the battery is long now... a shorter run from the battery to the hat shelf or anything back there would be better... it will work from the GPU port.. but a shorter run (counted from the battery terminals to the charger) is what you want.  The length of the additional wire must be added to the length of the wire from the connection point back to the batteries. 

Also.. you mention dual batteries?.. are they switched bat1/bat2? like the long bodies or are they hooked directly in parallel?

6' of charger wire is better than 2' of charger wire and 12' of airframe wire.   Are there any vents/ports in the rear of that plane that could be used?.. Since it would be a K conversion I don't know if there was an o2 door in the rear. 

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2 hours ago, peevee said:

Again, directly to the battery is not an option. 

Actually it is an option. You may decide not to, but it is an option. The batteries aren't permanently mounted back there. True they are in close quarters back there, but they have to be inspected and serviced at regular intervals and eventually replaced so you or a mechanic is going back there at some point. I have two batteries in the tailcone on my M20M. Every Mooney I've had in the past 23 years I've spent the time to connect the battery minder to the terminals and then fished it out through the oxygen port to plug in. I've zip-tied the long wires so that it doesn't interfere with anything else and I've never had an IA that had a problem with it. I link two batteries together with a 210-AY y-cord so that both of them get charged and desulfated at the same time. It may take a few extra minutes to do, but it's well worth it.

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