parasites

[egchewy79]

posted this on the other forum as well

So recently I was going to drive the MK4 to work and had a dead battery. 10v showing. Charged the car overnight and drove it later that week, no problems. I was out of town for a week and tried to start the car again but this time the battery was completely dead. Just took battery to battery store and it seems to be testing just fine, which suggests there's a parasitic draw somewhere.

This is a new issue in the past 18 mo. Coincidentally, I did replace a blown fuse for my seat warmers just prior to this issue occurring. I have the heaters wired up to my radio wire in the RF dash harness. They are the cobra heat heaters and each have an individual switch that lights up when on. This parasitic draw is occurring with key off, heaters off. Any ideas? My clock and FiTech ECU are the only 2 things I can think of that are always on, but haven't experienced this issue until recently. Would a bad ignition switch cause this issue? But still, the seat heater switches are off. Should I try removing the radio fuse and see if this solves things? The does the radio power have an always-on draw for radio memory? Any other ideas?

A bit more info, my seat heater grounds are attached to a kill switch that I also have my fuel pump relay ground connected to. The seat heaters and fuel pump are both disabled if this switch is turned off, which is often the case when the car is parked and turned off. Radio wire is on a 10a fuse at the box. The seat heater directions calls for a 10a current. The seats have a 4ohm resistance and on high setting has 13.5v w/ half that at the low setting. I did not wire in the provided 10a fuses that came w/ the kit as my wires are running in my trans tunnel and I figured if it blew a fuse, it'd be easier to replace at the fuse box than in the tunnel.

Last question...Is there an easier way to get the hold-down for the Breeze front battery box on by yourself? I have feeling that I'll need to get the car up on jacks and have a friend hold one end while we tighten the other.

[Fbird]

Have a Fitech on my old firebird. Noticed that if I did not unplug the display screen it would produce a slight draw and kill the battery. Replaced one battery thinking it was a bad battery. Almost lost the other one too until I learned that the touchscreen is not supposed to be left plugged in all the time. It creates a slight draw. Might want to try checking this out.

[egchewy79]

Have a Fitech on my old firebird. Noticed that if I did not unplug the display screen it would produce a slight draw and kill the battery. Replaced one battery thinking it was a bad battery. Almost lost the other one too until I learned that the touchscreen is not supposed to be left plugged in all the time. It creates a slight draw. Might want to try checking this out.

yeah, handheld is unplugged. I'm still thinking it's somehow related to the seat warmers and the fuse for this since this is a very recent occurrence after I replaced that blown fuse.

[J R Jones]

I do not know where the draw is coming from, Fbird has an observation but I am surprised that you can disconnect an ECU without issues.
With everything turned off, you can put amp meter leads across your fuse clips (fuse removed) individually to determine if there is current flow (draw).

Putting a kill switch on a ground wire(s) does not completely protect the circuit, an internal (short to ground) failure could still occur in the fuel pump or seat heaters,

A 10 amp fuse will protect one 10 amp circuit. Bunching devices, one radio and seat heaters accumulates load likely to exceed 10 amps. I would think a radio is not a 10 amp draw. Maybe, review the instructions.
jim

[FF33rod]

I would suggest getting a current meter and putting it in series with the batter positive, measure the current with everything off. If you see something significant, then remove fuses one at a time until the current drops, this will tell you which circuit you need to focus on.

Steve

[egchewy79]

I do not know where the draw is coming from, Fbird has an observation but I am surprised that you can disconnect an ECU without issues.
With everything turned off, you can put amp meter leads across your fuse clips (fuse removed) individually to determine if there is current flow (draw).

Putting a kill switch on a ground wire(s) does not completely protect the circuit, an internal (short to ground) failure could still occur in the fuel pump or seat heaters,

A 10 amp fuse will protect one 10 amp circuit. Bunching devices, one radio and seat heaters accumulates load likely to exceed 10 amps. I would think a radio is not a 10 amp draw. Maybe, review the instructions.
jim

Not running a radio. Just using the radio power wire.

[SourceLee]

A bad/failing alternator will put a parasitic draw on the battery. It's another item that remains connected to the battery when the ignition/accessory/run functions are off.

[egchewy79]

Correction, just checked and I'm using the WIPER power and not the RADIO power. I guess this eliminates the radio memory power from the equation. I'm going to get a multimeter and measure current draw in line w/ my battery w/ key off. I'll start pulling fuses until I find a drop in mA. If those are all normal, then I'll look into the alternator.

[rich grsc]

Check to see if alternator is hot or warm

[egchewy79]

Check to see if alternator is hot or warm

I was thinking about that. Unfortunately when I last checked, the battery was completely dead. I'll hook it back up and check after sitting overnight. First, I need to get a friend to help me reattach the hold down piece for the Breeze battery box. It's definitely a 2 person, 4 hand kind of job.

[svassh]

Heres a good test that at least narrows it to a circuit.

https://www.wikihow.com/Find-a-Parasitic-Battery-Drain

If nothing drops when pulling fuses unplug the alternator and check.

[phileas_fogg]

Hi Chewy,

Pretty much any multi-meter has a current draw measurement function, but you have to break into the circuit to make the measurement. For current draws over a few hundred milliamps, you'll use a separate, dedicated socket for the probe (see the picture https://smile.amazon.com/gp/product/B071JL6LLL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1). Your meter's instructions will show the proper connections.

Some multimeters have a lobster-claw-looking probe that goes around the wire under test, allowing you to measure the current without breaking the circuit. Last time I looked years ago, meters capable of measuring milliamps of DC current get expensive really quickly.

For your parasitic draw test, the less expensive meter is fine. You may need a helper to keep the alligator clips on each end of your battery circuit.


John