Voltage drain through cluster

[kickstartjoe]

My battery has been going dead in two to three days of sitting. The battery has been checked out and is good. I've narrowed the problem down to the instrument cluster. When I remove the cluster, there is no parasitic draw.
Any idea of what I can do to fix this problem?
Thanks,
Joe
2008 Expedition XLT SSV

 

[Bedrck47]

How much draw are you getting with the cluster in and with it out Post the numbers

 

[kickstartjoe]

Without the cluster, it is drawing less than .01 volt per hour, and with it installed, it is drawing between .04 to .05 volt per hour. I don't have the amperage figures.

 

[chuck s]

Volt per hour does not compute. Volts are potential (think water pressure like 40 psi). Amps are current flow (think gallons per hour.) One amp for one hour is an amp-hour and a standard measurement.

What are you measuring? Voltage? Flow? Where are you measuring current flow (amps)? Is it drawing 0.01 amp? Radio memory, remote lock/unlock, etc can easily draw this.

Fords typically leave the 12v "cigarette" outlets powered all the time. Anything there will draw current from the battery too.

-- Chuck

 

[ExpeditionAndy]

Just to stir the pot, check that your rear wiper is parked. If the wiper is stuck or stiff, it can draw a battery down in 1-2 days, depending on the condition of the battery. It is easy to eliminate. Lift the rear glass and move the wiper arm. Also check to see if the disk rotates to the park position.

 

[Big Brian]

Volt per hour does not compute. Volts are potential (think water pressure like 40 psi). Amps are current flow (think gallons per hour.) One amp for one hour is an amp-hour and a standard measurement.

What are you measuring? Voltage? Flow? Where are you measuring current flow (amps)? Is it drawing 0.01 amp? Radio memory, remote lock/unlock, etc can easily draw this.

Fords typically leave the 12v "cigarette" outlets powered all the time. Anything there will draw current from the battery too.

-- Chuck

I am glad somebody else noticed this...
...The comment about volts per hour
the only way I can make sense of it is if he means the battery voltage drops .01 volt per hour?

great reply Chuck

 

[kickstartjoe]

From last night to this morning, with the instrument cluster installed, the voltage dropped by .21 volt. Over 13 hours, that is .016 volt per hour, or a drop of one volt in about 60 hours (assuming linearity).
I removed the cluster after taking the second reading this morning, and 10 hours later, the voltage was .05 volt lower, for a drop of .005 volt per hour, or a drop of one volt in about 200 hours.
Yesterday, I measured the amps with all of the fuses in, and the cluster in place, and got .77 amp. I pulled fuse 26 "Instrument Panel Cluster" and it dropped to .52 amp.
Of course, even .52 amp is far too high, since a high of 50 milli-amps, or .05 amp, is, I think, spec.
I have problems beyond the cluster, but the cluster is a big contributor. Does the instrument cluster pass power on to anything else?
Thanks,
Joe
2008 Expedition SLT SSV, former police vehicle

 

[Bedrck47]

http://www.expeditionforum.com/threads/your-battery-keeps-going-dead-the-parasitic-draw-test.24600/

 

[kickstartjoe]

Thanks. I'll try that tomorrow.

 

[chuck s]

Battery voltage drops naturally and voltage drop won't provide the data you (and we) need. We need to know the parasitic amperage draw. If you have a voltmeter it's likely got an ammeter too.

Even a $6 Harbor Freight VOM will read amps. Connect in series with the Pos (+) battery terminal using some clamps to hold the leads in place. Amperage draw will display immediately. Have all the doors closed and the ignition Off before doing this. Block off things like door switches and don't try to start the truck or even turn on lights while the lil' meter is connected.

If the battery has a Reserve Capacity of 150 amp hours it has a useful capacity of about 62 amp hours before the voltage drops below 10.5vDV (dead). (Useful amp hours rule of thumb is RC/2.4 and works surprisingly well in predicting battery life.)

-- Chuck

 

[ExpeditionAndy]

http://www.expeditionforum.com/threads/your-battery-keeps-going-dead-the-parasitic-draw-test.24600/

Bedrck47, that was a great video in that post. I've never seen an amp meter that worked like a volt meter. I'm used to the camp on types. The method shown in the video certainly leaves out all room for doubt.