Parasitic draw

[Mickey_7106]

Does anyone know what the acceptable parasitic draw is for a 2001 Tahoe? My brother has been having on going issues with dead batteries. he was told by some mechanic outside pik npull that it was the SEO1 fuse ( guess he used some sort of test light method)

Anyways i had the truck sit over night and currently the 25A RDO AMP fuse is consistently pulling 1.0 mV which translates to 218 mA according to power probe tek website. The battery was at 11.6x Volts when i tested and the radio was removed and disconnected last night.

I know this method can be inaccurate, im waiting on a clamp meter and noco genius 10 battery charger to be able to perform a more accurate test

 

[Fless]

You'll be lucky (or spend a lot of money) getting a clamp meter to read DC milliamps as low as you need it. Mine has (or had, not sure yet) an intermittent draw that seemed to leave the radio and amp on at about 1.5a total draw. I bought a shunt and a digital meter to put under the hood so I could make sure mine goes to sleep properly; so far it's been good. And I recently replaced the driver's door latch just to be sure that wasn't the problem.

My '04 goes fully to sleep at around 25ma, but the auto HVAC head can take over 4 hours (GM spec) to go to sleep, although mine doesn't always take that long. When it's still awake the draw will be around 65ma for a couple of hours. These trucks should easily come in under 50ma after fully asleep, but that could also depend on your aftermarket accessories.

The 218ma draw -- just by value -- smells like a defective instrument cluster. They can get what's called silver migration on the circuit board. But you need to get a wiring diagram to see (all) what the RDO fuse feeds.

Do the radio and interior lights go off after you remove the key and open the door? If not, suspect the driver's door latch. Let us know how things go....

 

[Mickey_7106]

Thanks, i ordered a true rms klein cl390 for $75 on amazon. If i read the description correctly, it will read down to 200 microamps

You'll be lucky (or spend a lot of money) getting a clamp meter to read DC milliamps as low as you need it. Mine has (or had, not sure yet) an intermittent draw that seemed to leave the radio and amp on at about 1.5a total draw. I bought a shunt and a digital meter to put under the hood so I could make sure mine goes to sleep properly; so far it's been good. And I recently replaced the driver's door latch just to be sure that wasn't the problem.

My '04 goes fully to sleep at around 25ma, but the auto HVAC head can take over 4 hours (GM spec) to go to sleep, although mine doesn't always take that long. When it's still awake the draw will be around 65ma for a couple of hours. These trucks should easily come in under 50ma after fully asleep, but that could also depend on your aftermarket accessories.

The 218ma draw -- just by value -- smells like a defective instrument cluster. They can get what's called silver migration on the circuit board. But you need to get a wiring diagram to see (all) what the RDO fuse feeds.

Do the radio and interior lights go off after you remove the key and open the door? If not, suspect the driver's door latch. Let us know how things go....

 

[Fless]

I may be wrong but I don't think the clamp will read that low. The test leads will, but the meter will need to be in-circuit. I don't see where the specs show the amp clamp values.

Measures both AC/DC current and NCVT via the clamp and AC/DC voltage, DC micro-Amp current, resistance, continuity, frequency, duty-cycle, capacitance and tests diodes via the test leads, and temperature with thermocouple.

One comment: the "...25A RDO AMP fuse is consistently pulling 1.0 mV which translates to 218 mA..." A 25a Mini Fuse, if that's what you have, reads 1.0mv across it, the current would be 424ma, if I'm reading the chart correctly.

EDIT: if the draw is consistent then it should be relatively easy to isolate which circuit is the issue. Narrowing it down to the actual cause is the fun work.

 

[Mickey_7106]

You sir are correct. i was looking at the 15A fuse for some reason. i called klein tools. They told me the clamp will accurately read as low as 100 milliamps. Anything under is no good

I may be wrong but I don't think the clamp will read that low. The test leads will, but the meter will need to be in-circuit. I don't see where the specs show the amp clamp values.

Measures both AC/DC current and NCVT via the clamp and AC/DC voltage, DC micro-Amp current, resistance, continuity, frequency, duty-cycle, capacitance and tests diodes via the test leads, and temperature with thermocouple.

One comment: the "...25A RDO AMP fuse is consistently pulling 1.0 mV which translates to 218 mA..." A 25a Mini Fuse, if that's what you have, reads 1.0mv across it, the current would be 424ma, if I'm reading the chart correctly.

EDIT: if the draw is consistent then it should be relatively easy to isolate which circuit is the issue. Narrowing it down to the actual cause is the fun work.

 

[Fless]

You sir are correct. i was looking at the 15A fuse for some reason. i called klein tools. They told me the clamp will accurately read as low as 100 milliamps. Anything under is no good

Well, that'll certainly get you ahead of a large draw, so it should be convenient and worth it. Once you think you have it below 100ma you may want to do an in-circuit test to confirm the precise ma draw when it's fully asleep.

 

[Fless]

Eric has some good tips, in case you haven't seen this. He has others, too.

 

[Mickey_7106]

Haven't seen this video. Would have to make time for it.

Some notes:
Pulled instrument cluster. Still had constant 1mV draw.

Pulled dash climate control from dash, still had 1mV draw.

The radio has been pulled of for days but you can hear some noise or static from the front passenger speaker. After some fighting i disconnected the blue harness from the factory amp and now i have 0mV draw for that fuse and zero noise coming from the speakers. Is it safe to assume the amp is defective? My brother has told me before that he's had issues with no sound coming from the speakers but its intermittent

Eric has some good tips, in case you haven't seen this. He has others, too.

 

[Fless]

Curious. I'm not sure, but that could be. It seems that the radio should have control to turn on/off the amp and, with the radio removed, the amp should power down. Wonder if there is a bad connection at the radio or amp connector that keeps the radio from controlling that? I'd inspect and clean the radio connectors' pins, as well as the pins on the amp connector.

If the amp is staying on, radio in or not, you should be able to read voltage across the amp fuse.

The amp could also be defective internally, not obeying the radio commands. I'm not familiar enough with the theory of operation to know. The amp might be on (by design) all the time the ignition or RAP is active.

Also, check those interior lights to make sure they turn off when any of the doors are opened after removing the ignition key. RAP needs to be shut down.

 

[BG1988]

Does anyone know what the acceptable parasitic draw is for a 2001 Tahoe? My brother has been having on going issues with dead batteries. he was told by some mechanic outside pik npull that it was the SEO1 fuse ( guess he used some sort of test light method)

Anyways i had the truck sit over night and currently the 25A RDO AMP fuse is consistently pulling 1.0 mV which translates to 218 mA according to power probe tek website. The battery was at 11.6x Volts when i tested and the radio was removed and disconnected last night.

I know this method can be inaccurate, im waiting on a clamp meter and noco genius 10 battery charger to be able to perform a more accurate test

replace the battery its dead or weak..... the battery should last 1 to 1.5 weeks at 250mAh most batteries are rated to 50-80AH ....


have it load tested


I can run my dash camera several days no problem it uses 1 amp at 5volts or 200-215ma at 12v

i would check the charging system and disconnect the battery current detection/ voltage detection (it might light up the Battery CEL) to see if it actually charges up..