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Old 12-20-2017, 08:18 AM
mikeinFL mikeinFL is offline
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2003 Pathfinder
 
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Quote:
Originally Posted by bennyb53 View Post
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.

Last edited by mikeinFL; 12-20-2017 at 08:27 AM.
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