Parasitic Battery Drain (Fuse 9) - Any ideas?

[wagohn]

Hello all,
Not run the '76 bus in a week due to a busy work schedule. Went out this AM to start and the battery was so low it barely cranked, and then died trying. Thing is, I fully charged the battery last weekend and since then it sat.
The PO but a new battery on as the bus would drain on him too. We thought we solved the issue because the bus only charged at 12v, so we replaced the voltage regulator and now get 13.6v running down the road. However, it seems there's something else going on now.
We hooked up an amp tester between the negative battery terminal and it's cable. We saw 1.0 on the tester. Then we removed, one-by-one, each fuse. All removals returned 1.0 at the gauge except fuse 9. When we removed fuse 9, the tester went down to 0.6.
Therefore, I'm assuming I have some drain with the interior lights, etc, though none are ever turned on. I guess my bigger question is; Is 0.6 expected? I'd have assumed next to nothing.

Edit: We added a stereo with Bluetooth and wired that to be always powered. I just disconnected the stereo completely and tested again, still at 1.0. That's the only thing we added. Strange.

Thanks
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1976 VW Transporter, 2.0 FI Engine

[busdaddy]

Fuse #9 is the accessory fuse, so whatever it powers wasn't put there by VW, it left the factory unused (unless it had a factory radio or ambulance fans listed on the M plate). Time to start following wires.
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[wagohn]

[aeromech]

Seems like you’re doing a good job troubleshooting. Good battery. Good alternator. Something is eating amps. Remove all the fuses. Does the battery show a drain?
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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
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Boeing 727,737-200-300-400,757,767
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DC9/MD80
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VW Type 2 1971 (3 ea.) 1978, 1969
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[busdaddy]

[SGKent]

i found a bad trailer hitch light convertor on the 04 Sable causing it once, and a defective relay in a circuit designed to only allow parasitic drains on a couple circuits for so many minutes after the car is turned off. The bus should be pretty simple. Just look for aftermarket electronic accessories that have memory like radios, amps, converters that run 24x7 when they aren't needed etc.. My 1977 bus holds a full charge for months sometimes. The Sable about 3 - 4 weeks. I understand the MDX can be 3 weeks or so. What do people do when they leave the car at the airport for a 2 week vacation... .
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[wagohn]

You are correct, Busdaddy, #9 is the aux fuse. I think I will take out #9 tomorrow and see what stops working. Then go from there. Other than the now disconnected radio, the bus has spotlights, extra gauges, and extra 12v sockets. I will start to disconnect them one-by-one and see what I get.
Thanks, everyone.
_________________
1976 VW Transporter, 2.0 FI Engine

[aeromech]

I use a dc amp clamp to measure current flow. DC clamps aren’t as common as AC clamps. How are you measuring current flow?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Wildthings]

What units are you reading? Saying 1.0 or 0.6 doesn't mean much without mentioning the units you are reading. Amps? Milliamps? Volts?

Your problem could be that your battery is sulfated. Batteries don't recover well from being fully run down. They need to be put on charge for a long time (like days) to bring them back up to close to what they were and preferably overcharged for a bit which you can't do with most homeowner sized battery chargers. A 30 minute charge with the engine idling out in the driveway just doesn't cut it.

[aeromech]

It’s true. Start batteries differ from deep cycle batteries in that a deep cycle battery can be run down low and recharged many times. A start battery loses life once in goes below 10 volts. You can however “recondition” a depleted start battery if you have a charger that’s made with that mode like I have but it’s never guaranteed to work.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[wagohn]

I admit, I don't know much about multimeters but I had the tester set to amps - it was either the first or second setting shown below (400 or 40). Each fuse read between 0.99 and 1.05, except for #9 that, when removed, resulted in a 0.60 reading.
Thanks again.

_________________
1976 VW Transporter, 2.0 FI Engine

[bsairhead]

Check battery and ground strap connections first. If you have .6 amp drain you still have a drain. Not acceptable. Set your multimeter to ohms, Take the battery out of the loop and look for resistance. Pull the negative off the battery and meter between the positive side of the battery and the ground cable (NOT THE BATTERY NEGATIVE). You can do this up front with a clean ground point and the main positive wire to the fuse block but
on most VW's it goes through the ignition switch first which could be the issue. Have your helper look at meter or rig a way to watch your meter upfront. Pull fuses one by one until you have 0 ohms. Determine what that circuit controls from the factory even though it could have changed. Then start playing with that circuit. Ignition first, move back forth ax start off watching meter. Play with lighting controls, wiper controls etc. Most switches in the on (closed) position will show resistance. I do it this way so if I find a loose or frayed or miss landed wire I can deal with It without the possibility of smoking wiring or burning up my bus.

[aeromech]

I you misuse your amp meter you will blow its internal fuses. Ask me how I know
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[bsairhead]

[telford dorr]

Bottom line: a stock bus (with stereo disconnected) should show ZERO current draw with the key off and interior lights off (doors closed). Anything greater than that, and you're going to have a problem.

This problem is inevitably caused by something added or something changed in the electrical system: stereo, gauges, fuel pump, lighting, horns, camping equipment, etc.

Trace the wires coming from fuse 9 and see what all it is powering.

Try removing the fuse and connecting a small (LED) test light in its place. If it lights up, disconnect attached loads until it goes out.
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Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[bsairhead]

telford dorr knows way more about VW electrics then most people on this site. I am an electrician that plays with Volkswagens. Take his advise when given.

[wagohn]

[mikedjames]

[wagohn]

[wagohn]

In all fairness, I told you guys I'm not the best with a multimeter.
Turns out I was testing the negative battery pole and not the negative battery cable. I hooked things up correctly and now I'm getting 0.3, no matter what I do. I took out all the fuses and disconnected the spotlights and still 0.3. it was a minus 0.3 but I'm assuming that's not important?
After a couple of driveway starts my battery is now at 12.76v. I disconnected the negative cable and will retest tomorrow to see how much drop of volts in 24 hours - if any with the battery isolated. Still not sure if the 0.30 was actual or phantom. I was still getting 0.30 with all fuses out and the singular positive cable attached to the battery.
Thanks.
_________________
1976 VW Transporter, 2.0 FI Engine