Battery drain

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satchmo
Old School!
Location: Crosby, MN
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Post by satchmo » Mon Apr 05, 2010 8:15 am

It looks like the radio is the offender. It is an aftermarket Kenwood with a harness that has been professionally grafted into the stock wiring (you can tell by the wire crimps). Taking the faceplate off had no effect on the battery drain. There really isn't an on-off switch either. But when the radio is plugged into the harness, there is a big spark at the neg. battery cable when I re-connect it. Radio unplugged, no spark.

Anyway, I have no trouble finding a new radio to put in there. But here is my next question (and remember I am electrically challenged): Can putting new speakers in the back of my van be a contributor to the battery drain? It seems not to me since the speakers should be off when the radio is off, but what do I know?

Vanagons have speakers that came stock in the rear A/C cabinet. I took out the cabinet and fabbed up some enclosures for some new Boston Acoustics speakers. I just used the same wires as the stock configuration. I'm thinking the battery drain issue started after the speaker switch. Could this cause a problem?

I'm not a complete idiot when it comes to electrical systems. And to prove it I will go check whether there is voltage at the rear speaker wires with the radio off to see if the speakers might be a problem, AS SOON AS IT QUITS SNOWING!

Thanks, Tim
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Sluggo
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Location: Portland, Or.
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Post by Sluggo » Mon Apr 05, 2010 9:00 am

I've never heard of speakers causing a drain. There are two wires providing power to the stereo. One receives constant power and the other is ignition only. Disconnect one and check for spark and then check the other. The constant line should produce a spark. Is your stereo's power + connected to an ignition only wire? It should be. If the ignition only line is is wired for straight power, that would cause a drain.

I had a '91 Jetta with the same problem. The stereo had developed a short internally. I had to pull the fuse for the stereo when I parked for the night to keep the battery from draining.
:vwgauge420:

1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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dtrumbo
IAC Addict!
Location: Mill Creek, WA
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Post by dtrumbo » Mon Apr 05, 2010 9:08 am

The speakers themselves aren't your problem. That said, the wiring might be. I remember on the '84 Vanagon that I owned, the factory radio actually grounded one side of the speaker outputs. This prevented me from using the factory wiring when I installed an aftermarket radio since it's a no-no to ground either of the speaker connections. Since the problem appeared with the speaker install, as weird as it seems, it might be the place to start looking. Are the speakers up front still stock? If so, you might be experiencing the issue I did. You could always just unplug your new rear speakers and see if the problem goes away or the spark diminishes. The clock/preset current draw for any radio shouldn't be enough to draw enough current to be described as "a big spark".
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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airkooledchris
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Location: Eureka, California
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Post by airkooledchris » Mon Apr 05, 2010 4:48 pm

ditto what sluggo said about two power wires for the stereo.

one of them is supposed to provide constant power, so you don't lose your clock and favorite stations. if that is draining more than it's supposed to and you don't care about it's clock and fav stations, just connect both to the switched power instead so when the key is off the power isn't available to drain.
1979 California Transporter

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