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-   -   parasitic drain on 7.5a fuse Elect B (https://x.nissanhelp.com/forums/pathfinder/30223-parasitic-drain-7-5a-fuse-elect-b.html)

mikeinFL 12-14-2017 07:36 PM

parasitic drain on 7.5a fuse Elect B
 
My 2003 Pathfinder battery drains below 12.4 each night. I tested and found a 0.09 amp drain. I think this is too much? Drain should not be higher than 0.05, correct?

When I pull the 7.5a Elect B fuse left interior, it goes to 0.00

Apparently Elect B connects to various interior lights and things? Some other forum someone found it was the SECU, not sure what that is. What should I start checking? and how?

smj999smj 12-17-2017 08:27 PM

Shouldn't be more than 0.05 amps. You need to get a wiring diagram of the complete circuit and disconnect loads one at a time until you find the draw. Start with the easiest ones to get to first.

mikeinFL 12-18-2017 06:18 AM

thanks, last night I took my battery off the vehicle by taking the neg off. Volts was 12.74. This morning, 14 hours later, the battery is at 12.59 volts. This is with battery not connected. Should a battery drain 15 volts over night by itself?

eruby 12-18-2017 07:13 AM

If you live in Florida (MikeinFL), stop by your local auto parts shop (Advance Auto, Auto Zone, etc.) and have them do a battery test.

mikeinFL 12-18-2017 09:06 AM

Quote:

Originally Posted by eruby (Post 103383)
If you live in Florida (MikeinFL), stop by your local auto parts shop (Advance Auto, Auto Zone, etc.) and have them do a battery test.

New is battery bought in July. I had a shop do a battery load test a few days ago and it passed. However they used a hand held tester and I just read somewhere hand held does not do a proper load test. true?

bennyb53 12-20-2017 12:45 AM

1. Your number is flawed. From 12.74v to 12.59v is not 15 volts. It is 15 millivolts (15mV). A new battery is 12.6V so at 12.59v is just fine. At 12.74v is slightly overcharged that may indicate a problem with the Alternator's voltage regulator. A failing/or failed alternator will not charge the battery or may even overcharged the battery which is not safe

A load test is done to determine if alternator is working or has failed. It is not done to determine a Parasitic draw. If you have a parasitic draw, it means your battery is being drained over a 2 or 3 day period or if a massive draw the battery is drained overnight.

I suspect your issue is the alternator so you can do the load test. With a volt meter or digital multi meter take a battery voltage reading before starting the car. Start engine and after reaching normal operating temperature turn on your headlights, turn signals radio, fog lights if equipped, a/c or heater and fan on high. Then take battery voltage reading and you should get 14.5 to 14.7 volts. If you get less than 14V you need to replace your alternator.

mikeinFL 12-20-2017 07:18 AM

Quote:

Originally Posted by bennyb53 (Post 103393)
1. Your number is flawed. From 12.74v to 12.59v is not 15 volts. It is 15 millivolts (15mV). A new battery is 12.6V so at 12.59v is just fine. At 12.74v is slightly overcharged that may indicate a problem with the Alternator's voltage regulator. A failing/or failed alternator will not charge the battery or may even overcharged the battery which is not safe

A load test is done to determine if alternator is working or has failed. It is not done to determine a Parasitic draw. If you have a parasitic draw, it means your battery is being drained over a 2 or 3 day period or if a massive draw the battery is drained overnight.

I suspect your issue is the alternator so you can do the load test. With a volt meter or digital multi meter take a battery voltage reading before starting the car. Start engine and after reaching normal operating temperature turn on your headlights, turn signals radio, fog lights if equipped, a/c or heater and fan on high. Then take battery voltage reading and you should get 14.5 to 14.7 volts. If you get less than 14V you need to replace your alternator.

yes it's millivolts,. thanks

Again last night, I drove 15 miles, got home, checked the battery, it was 12.88 volts. I pulled the Elect B fuse to stop any drain (DCamps=0). This morning I checked the battery it was 12.64 volts.

You say that's ok. It's normal to drop that much without a load? And is it ok to charge battery that high? I think it hit 12.9 once.

The shop checked my alternator but didn't have me turn on all those things. He said it was a little high, 14.7 or something. I will try your test.

As for parasitic drain, it still shows 0.09 dc amps. I pull "Elect B" fuse now every night to stop drain. I called Nissan and master tech said it should be .05 or lower. I do have a possible clue- the door light always stays on when vehicle is running but all doors are closed, including back hatch that swings up. All some lights are switched off however, so I know there is no dome light drain.

mikeinFL 12-20-2017 08:24 AM

Quote:

Originally Posted by bennyb53 (Post 103393)
...

I suspect your issue is the alternator so you can do the load test. With a volt meter or digital multi meter take a battery voltage reading before starting the car. Start engine and after reaching normal operating temperature turn on your headlights, turn signals radio, fog lights if equipped, a/c or heater and fan on high. Then take battery voltage reading and you should get 14.5 to 14.7 volts. If you get less than 14V you need to replace your alternator.

I did the test with lights and ac full on. At 2000 RPM. Volts= 14.51 steady.

So charging looks ok? Why does it charge the batter to 12.88? And why does battery drop back to 12.6 range overnight?

I'm going to try and check the alternator diodes via this method I found. Is a valid diode test?:

" Touch the big post on the alternator (the positive terminal post on the alternator) with the red lead of the multimeter, and touch the other lead on the alternator case. With the multimeter set to measure resistance, it should measure more than 550 ohms if the alternator diode is any good. Make sure when you do it that the battery is disconnected to prevent any electrical shorts or shocks."

mikeinFL 12-20-2017 09:45 AM

I found the cause of the door light- I pushed on the back hatch window and the door light went out. I tested drain load before and after and it dropped .01 with it properly closed. Drain now shows .07

Cusser 12-21-2017 05:21 AM

Good - you found a drain.

I just saw this thread, or I would've posted: Does your truck have issues starting the next day? What if you left it unused a couple of days?

I have a 2004 Frontier 100 miles away, and I've had it sit unused for up to 3 months and it still started right up.

So if one doesn't have starting issues, don't stumble in your panties worrying about some millivolts at the battery.

mikeinFL 12-21-2017 06:06 AM

Quote:

Originally Posted by Cusser (Post 103407)
Good - you found a drain.

I just saw this thread, or I would've posted: Does your truck have issues starting the next day? What if you left it unused a couple of days?

I have a 2004 Frontier 100 miles away, and I've had it sit unused for up to 3 months and it still started right up.

So if one doesn't have starting issues, don't stumble in your panties worrying about some millivolts at the battery.

summary and current status:

It would not start because in the morning the battery had dropped under 12 volts. I tested for a drain and found 0.40 amps. I pulled the speaker amp fuse. Drain dropped to 0.09. I closed rear window hatch. Drain is at 0.08 now.

I'm told it should not be higher then 0.05 so I still have a drain issue. Something has a 0.03 load and it's on a fuse that says "Elect B" which is on many things, including power doors, etc. For now, I pull that fuse at night and put it back in when I drive again. This works as vehicle starts ok in the morning.

Battery passed EXP800 load test:
Measured: 649 CCA
Rated: 700 CCA

I found that after driving a while the battery charges up to 12.88v area. And with no load will drop back to 12.6 range overnight. Is this normal for a battery?

I tested the alternator at 2000 RPM, lights and AC on: 14.51 steady volts.

Autozone code check found no problem.

I have Haynes Repair Manual and fuses are numbered and I think Elec B is fuse 26. Connects to lots of things including Daytime Light COntrol Unit (fog lamps, parking light, etc), door locks, power windows, etc and ECM

Cusser 12-21-2017 08:50 AM

Quote:

Originally Posted by mikeinFL (Post 103411)
It would not start because in the morning the battery had dropped under 12 volts.

OK, apologize - because you do have a real problem.

When it would not start, did the starter click, or grunt and stop? Did you measure voltage across the battery terminals DURING the attempt to start, like 10 seconds in?

What voltage were you reading on those mornings? I've seen batteries reading under 11.5 volts that readily could spin an engine and start a vehicle.

Did you clean the connections on the starter itself?

Download the factory service manuals here, might have to download one chapter at a time. Nissan Frontier Factory Service Manuals

On my '98 Frontier, had an intermittent in the electrical part of the ignition switch, lost some batteries until I figured that out. So I had to replace that, was pretty straightforward, just the steering wheel upper and lower covers had to come off.

smj999smj 12-21-2017 01:03 PM

Quote:

Originally Posted by mikeinFL (Post 103411)
I found that after driving a while the battery charges up to 12.88v area. And with no load will drop back to 12.6 range overnight. Is this normal for a battery?

I tested the alternator at 2000 RPM, lights and AC on: 14.51 steady volts.

The battery isn't charging "up to 12.88" after driving, it's that the battery voltage was charging at 14+ volts and now that the engine is shut off, the static charge of the battery is still elevated from being charged at 14+ volts while driving and it needs a little time to settle back down. This is perfectly normal. Usually anything around 12.2-12.6 volts (static charge) is perfectly acceptable. Charging system voltage can range from 13.2-15.5 volts and be within range, but most late model Nissans tend to sit in that 14.4-14.7 charging volts range. Btw, charging system voltage should be tested at idle and at 3000 RPM, with both loads "on" and loads "off." It's also a good idea to check the battery cable connections to make sure they are clean and tight whenever there are electrical issues. Some batteries, especially those made by Johnson Controls (which makes about half of the automotive batteries on the market), are made with smaller diameter battery post than they used to be years ago and this causes a lot of poor connection issues.


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