Charging issue

Tiny
DIVIDES
  • MEMBER
  • 2011 HONDA ODYSSEY
  • V6
  • 2WD
  • AUTOMATIC
  • 133,000 MILES
Bought it as is. Jumped it before I did and it started and drove fine with the jumper on.
Checked battery with load and it's bad.
Checked battery voltage while running and it was 11 and then and sliding. Alternator looks fairly new, not sure if it has been replaced.
Aren't there fuses for the alternator? If so I would like to check those, and then get a new battery and then do more digging.
Monday, April 25th, 2022 AT 2:01 PM

13 Replies

Tiny
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Forgot to add that, belt is okay, but I can push it with my hand and it will go as far as 2-3 inches. So not sure if a bad tensioner can cause the alternator not to charge as it should.
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Monday, April 25th, 2022 AT 2:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Is the present battery producing any voltage? Also, with the engine running, you should see around 14v at the battery, so 11 is certainly an issue. I'm not sure how it was tested, but here is a link that explains how it's done. See if this is different than what you did.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

If the belt is loose, it may not be spinning the alternator fast enough, but I would think you would hear a squealing sound. Is that present?

If you look below, I attached the charging system wiring schematic. Note there are a few different fuses that should be checked. I highlighted them.

When checking the fuses, in addition to checking the fuse condition, confirm there is power to and from them. Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know what you find.

Joe
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Monday, April 25th, 2022 AT 7:25 PM
Tiny
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Out a new battery started right up, checked voltage at battery was 14, same at alternator. Two minutes later dropped to 12v both locations. Battery terminal was not so great so tightened it and checked now 14v.
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Thursday, April 28th, 2022 AT 9:49 AM
Tiny
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Belt.
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Thursday, April 28th, 2022 AT 12:40 PM
Tiny
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If I press with my fingers on the harness connector of the alternator voltage changes to 14.2v. Not sure if alternator or connector are bad.
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Thursday, April 28th, 2022 AT 12:45 PM
Tiny
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I did it several times. Is the regulator in the back of the alternator? I don't see a thing wrong with the connector.
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Thursday, April 28th, 2022 AT 1:03 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,192 POSTS
The idea that you identified voltage changes when pushing on the wiring, which is likely where the problem is.

There will be a heavy gauge wire from the battery which has 12v at all times. Make sure it is tight and not corroded and the wire is not damaged in any way. (Letter B in pic 1)

If that checks good, disconnect the two connectors (letters A and C in pic 1) and inspect for pin damage where the connectors come together, inspect the wiring for any damage, or corrosion, and make certain one of the pins isn't loose in a connector.

Since there are three different connections, see if you can identify if there is one that causes the issue. That will help you narrow it down.

Also, it sounds like the alternator isn't the issue. However, it could have an internal wiring issue right off the connectors.

Please keep in mind that there is always power to the alternator. I would recommend disconnecting the negative battery terminal prior to checking connections.

Let me know what you find.

Joe
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Thursday, April 28th, 2022 AT 6:33 PM
Tiny
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Yes, the heavy gauge wire at the alternator is tight and there is no corrosion. I tried to move it to see if there are any changes in voltage but none. A and C are one connection. A is just the rubber piece on the top of the connector. I will recheck for any pin damage. There is a bit of play coming from the alternator not the connector itself that is why I am suspecting an internal alternator damage.
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Thursday, April 28th, 2022 AT 7:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

It is very possible. Let me know what you find or if you have questions. If there is nothing obvious with the external wiring or connectors, you may want to remove the alternator and see if you can move the connectors or take it apart and inspect it.

Let me know.

Joe
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Thursday, April 28th, 2022 AT 7:16 PM
Tiny
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A new alternator and tensioner took care of it. Thanks
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Saturday, May 7th, 2022 AT 9:33 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Thanks for the update. Was the issue related to the wiring harness or was it something loose internally? I'm interested in knowing.

If I don't hear back from you, please feel free to come back anytime in the future. You are always welcome here.

Take care,

Joe
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Saturday, May 7th, 2022 AT 9:07 PM
Tiny
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Not sure, but the back of alternator where harness connects has free play, same time the tensioner is bad.
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Sunday, May 8th, 2022 AT 6:35 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,192 POSTS
Hi,

It sounds like that is where the problem came from. Regardless, I'm glad to know it's fixed. Again, please feel free to come back anytime in the future.

Take good care of yourself,

Joe
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Sunday, May 8th, 2022 AT 7:19 PM

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