Aux battery short?

[pomfritz]

My aux battery system has developed an issue. When I plug an ext cord into the hookup. There is a little pop and sometimes a smell. The tang on the hookup plug shows a little black burn mark. If I leave it please plugged in it seems fine. I've checked around and the connections seem good. No fuses have blown. I took apart the hook up box and it looks good. Connections are tight and nothing touching anything it shouldn't.

Any suggestions on what to check? I usually fix these eventually but it's not easy for me to diagnose stuff. Just learning as I go along.
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83.5 233K. GW 2.3, SS exhaust, My German Frau named her Stefi

[termuehlen]

If I am understanding correctly, your 120V hookup on the exterior of your van is where you are noticing this issue. Is that correct? Which "tang" is discolored? Ground, neutral or hot? The 120V circuit in your vehicle should be totally separate from the 12V system. The outside 120V hookup, the rear bench 120V outlet and the 120V outlet inside your cabinet are all wired together, but totally separately from the rest of your wiring. A diagram can be seen in this thread:

https://www.thesamba.com/vw/forum/viewtopic.php?t=617624&highlight=shore+power+wiring+diagram

Is there anything plugged into either of your outlets when this occurs? Unplug the devices and check again. Also inspect all visible heavy gauge "romex" style house wiring connected to your outlets.
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1988 Westfalia automatic Subaru OBD1
1986 syncro tintop wbx

[timichango]

My guess is that the hookup box has an internal short — residual moisture, contamination, or a physical short. I'd replace the box and go from there. For the cost of a new box, I'd want to ensure that I was starting from a known-good initial 120v connection point before moving on to troubleshoot the van's interior AC wiring.

If you want quicker information about whether the extant box is OK or not, pop it off of the van, disconnect the wiring from it so that it's free from the van, and use a multimeter to test continuity between its connection points in the back. IMHO this sounds like a short — either consistent or intermittent (ie. it might be shorting intermittently when you wiggle the extension into place, and joggling the box's internal connections around, due to some kind of internal structural failure (eg. cracked plastic allowing a contact to temporarily rotate into another one).


Also: does this happen with a different extension cord? Do you know with certainty that the cord(s) you're using are solid? Do you know that the outlet it's connected to on the source end doesn't have some kind of electrical fault?
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Vroomhilde-San: Our 1991 Silver Vanagon Westy automatic + Subie EJ25

[pomfritz]

The right tang is discolored. (this would be if you are looking at it as you normally would be standing in front of the box.) What would this tell you?

I took the box apart and everything looked tight, no moisture seemed present. Do the modern electrical boxes fit this and have the right screw holes?

I think it's something here or earlier, like maybe the wall outlet, I will double check that. Inside the van, the wire goes to an outlet box that is GFCI protected, this box is the one by the rear seat and above the 12V outlet. And then from there the wire goes to another outlet box inside the rear seat area and that is what the charger is connected to. The GFCI in the van is not tripping, thought where the extension cord is plugged into is GFCI protected too and that is not tripping.

I plugged one of those plug outlet testers into the end of the extension cord and it looked good, no error lights.
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83.5 233K. GW 2.3, SS exhaust, My German Frau named her Stefi

[Paulbeard]

Aux power (12v) or shore power (110v)? Sounds like the shore power connection, might be worth changing the title for more/better traction.
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Currently -> Frida: 87 Tizian Red (mostly) Vanagon GL Westfalia w/ 2.0L ABA conversion
Formerly -> Steward of a 73 Super Beetle (Beater) and 67 Beetle 1300 (Little Max) both names by POs

[fxr]

[pomfritz]

Thanks for that. I charged up the system with it plugged into shore power, it once again made that little spark but no smell or anything else wierd, no overheating of anything. I don't recall if doing that earlier and will keep an eye on it.
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83.5 233K. GW 2.3, SS exhaust, My German Frau named her Stefi

[climber2377]

If you unplug the charger from the outlet in the van when you plug the van in on the outside or you plug in the van side (female end of the extension cord first) the arc should either be nonexistent or it will have moved to the male side of the cord when you plug in to the outlet you are going to use. Best to keep any and all sparks away from the van. If you plug the charger into the outlet in van after the van is plugged into shore power, does the plug for the charger arc? Maybe the charger is going bad and drawing too many amps? Maybe it's normal, I'd just be cautious around any gases.
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[email protected] 84 Westy 1.9 waterboxer > 2001 Legacy 2.5L sohc w/ subarugears 5MT Ty754