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Discussion Starter #1
So I kept an online scan tool that does real time monitoring and I was able to capture the battery voltage during operation. The battery when checked with a volt meter shows 14.1 at idle . There are times where it drops to a very low voltage
133835
 

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When you checked voltage at idle was the alternator under heavy load (headlights on, both blowers running at full speed)?

My first thought is bad alternator since 12.7V is the highest measurement while the Pilot is being driven.
 

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How old are both the battery and the alternator? Is the alternator the original one?
 

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Discussion Starter #4
When you checked voltage at idle was the alternator under heavy load (headlights on, both blowers running at full speed)?

My first thought is bad alternator since 12.7V is the highest measurement while the Pilot is being driven.
Yes under heavy load with everything running Thought when under load it’s showing a range of 13.2 to 14.1 on the meter also the same on this software during highway full speed tests
 

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Discussion Starter #5
How old are both the battery and the alternator? Is the alternator the original one?
No not possible at 220k the Alternator was replaced 80k ago OEM and the battery is a Walmart brand replaced coming up to 2 years ago this summer.
 

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I’m still thinking the alternator is starting to fail, but having the battery load tested wouldn’t be a bad idea before swapping the alternator.
I’m guessing you’ve also checked the condition of the battery posts, positive and negative cables, and all those cables connection points.
 

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I monitor voltage in my old truck with dumb power management and on our newest with smart power management. Both can show 12 when driving, the smart one when the battery is fully charged and the dumb one with headlights, heater etc on full blast.
So I’m not convinced that a single test like this is enough to replace anything.
Wife’s car gets little usage. When it does it’s short journeys.
Recently it flashed up a low voltage warning. I was about to run off and replace the battery (six year old) but testing revealed 14.4 after starting at idle and 12.1 before the start. I charged it overnight and make a point of using it on any longer runs especially in winter when headlights and heaters are in use. It’s just fine.
 

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Discussion Starter #9
So with the heat wave here in NY i tested the battery using the video that XGS Posted as reference
Battery Voltage before start :12.38 Volts
Voltage during crank : 11.21 Volts
idle voltage : 14.21 volts
voltage dropped down to 13.28 volts when headlights , heater and wipers were put on
voltage went back up to 14.28 volts idling with load

I guess the warm weather has allowed the battery to run as normal
 

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12.38 volts is a tad low for a no-load battery. A healthy battery with no load is 12.5-12.8v. But I like to measure that disconnected, fully charged, then let it rest overnight. 6 cells, 2.1v per cell.

The numbers while charging look good to me, 13.3-14.3v
 

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Discussion Starter #12

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All good info posted on normal ranges for battery voltage parked and when running. Consider getting the battery+alternator checked out free at auto parts store like Advance/Autozone. I keep a plug-in voltmeter to monitor the battery/charging system or charge my phone etc
 

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Discussion Starter #14
That unit doesn’t give you an accurate reading since the 12v ports are always have a fuse of some sort. They are not direct wired to the battery. Mine is connected in the obd port so there is an unfused 12 v at all times .
 

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That unit doesn’t give you an accurate reading since the 12v ports are always have a fuse of some sort. They are not direct wired to the battery. Mine is connected in the obd port so there is an unfused 12 v at all times .
May not be as accurate as a good multi meter but the consistent readings provided should alert me if there is an issue with the charging system or load. I think it's convenient and serves dual purpose (USB) for $12. On older vehicles the OEM volt meter in the dash probably wasn't super accurate either.
 
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