Battery Indicator Oscillating

Page 1 of 2  
This is an intermittant problem that only happens when driving with the headlights on -- but does happen every time. Any ideas how to troubleshoot it?
For awhile the needle would oscillation between the normal 50-60% position a few degrees after driving a half hour or more with the headlights on. Then I cleaned all the connections in the starting systems from battery terminal to hot connections and grounds, and the problem stopped.
Then last week, I had driven to a store at dusk with the lights on - no problem indicated. I left the lights on for 20 minutes while in the store. Then when I started, the battery needle start oscillating from 50% to 100% regularly, and the battery warning light started blinking off and on.
Car was running fine so I turned off the headlights and just put on the parking lights so I could drive the 2 miles home. After driving about 1/2 mile the oscillating and flashing stopped.
I have tried to duplicate the problem so I could show a mechanic, but all is back to normal for now.
Without knowing anything, I would guest that the computer detected some kind of low voltage and the swinging and flashing was an attention-getter, and not the actual reading.
Any ideas how to troubleshoot this?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/21/2016 1:17 AM, Snuffy "Hub Cap" McKinney wrote: ...

My money would be on the internal regulator in the alternator is acting up...
--





Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 21, 2016 at 8:20:56 AM UTC-4, dpb wrote:

That's a likely possibility. I'd start with having the battery load tested, which you can get done at most auto parts stores for free. Many will also test the charging system at the same time. If the battery is good, you're pretty much left with the alternator or a bad connections. The alternator common failures are either the VR already mentioned, or the brushes wear out. Those can usually be replaced separately but most people just swap out the alternator for a rebuilt one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 21 May 2016 07:39:00 -0700, "Snuffy \"Hub Cap\" McKinney"

Or the brushes are worn out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 21 May 2016 07:39:00 -0700, "Snuffy \"Hub Cap\" McKinney"

Sadly, the answer is basically no. You MIGHT be able to trick it into misbehaving again by putting a carbon pile load tester on the battery to draw down the voltage with the vehicle running - but I wouldn't count on it. That's why, knowing the problem was in the alternator, and having already replaced the regulator and brushes once on mine, I simply replaced rhe alternator when it started intermittently doing it again. I couldn't be bothered digging deaper into it for the $30 cost of a used, very recently rebuilt unit from the local "used parts emporium"
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks. $30 is a bargain. Alternators here are $150 new with lifetime warranty, $100 rebuilt w/ 1 year. If it were easier to swap out, that's what I would do. Still looking for a way to isolate to battery or alternator first. Already checked that connections are all good.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 21 May 2016 14:20:33 -0700, "Snuffy \"Hub Cap\" McKinney"

I checked the wreckers and took the best one they had - had been installed less than 2 weeks bdfore the car was wrecked and cost the same as a 10 year old one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 21, 2016 at 5:21:34 PM UTC-4, Snuffy "Hub Cap" McKinney wr ote:

t I would do. Still looking for a way to isolate to battery or alternator first. Already checked that connections are all good.
Driving over to one of the auto parts stores that does free battery and cha rging system tests is too hard?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 21, 2016 at 8:20:56 AM UTC-4, dpb wrote:

get the battery load tested, batteries can get internal intermittent shorts. had that happen once, it was terrible and couldnt be found. the battery was pretty new.......
finally decided to repplace battery, problem went totally away..
a year later a buddy cut the batter apart andfound on cells plate was bent, and must of intermittetly shorted
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

battery was pretty new.......

Thanks BH. Will check it out. I remember that the meter started slightly cycling from time to time when the headlights were one before the battery was replaced.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 5/21/2016 2:17 AM, Snuffy "Hub Cap" McKinney wrote:

Leaving the lights on 20 minutes would put more load on the alternator when you did start the car. The first thing that comes to mind is that for some reason the alternator is unable to work properly under high load.
The second thing that comes to mind is some serious sounding problems have simple solutions. Higher load makes the alternator work harder. It can be something as simple as a slipping belt. I'd tighten or replace it before rebuilding the alternator. Yes, I've seen it happen more than once. .
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 21, 2016 at 10:59:03 AM UTC-4, Ed Pawlowski wrote:

t it?

Then I cleaned all the connections in the starting systems from battery terminal to hot connections and grounds, and the problem stopped.

. Then when I started, the battery needle start oscillating from 50% to 10 0% regularly, and the battery warning light started blinking off and on.

mile the oscillating and flashing stopped.

and not the actual reading.

Good point about checking the belt.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/21/2016 10:00 AM, trader_4 wrote: ...

Albeit doesn't virtually everything now use just the single multi-rib serpentine belt with the auto tensioner setup? Not to say can't eventually stretch where there's insufficient takeup and I have had the tensioners fail/hang up where not doing its job but overall not nearly the issue used to be w/ separate, manually adjusted v-belt setup.
The oscillating nature makes me wonder also about the symptom, but could alternatively (so to speak :) ) grab/slip a little I suppose...
Agree the symptom being so much more observable after the battery drain is indicative it's happening under the heavier load...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 21, 2016 at 12:44:00 PM UTC-4, dpb wrote:

Agree, the belts today would typically be a lot less susceptible, particularly with automatic tensioner.

I'd say an alternator problem, most likely VR or brushes, is the most likely problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 5/21/2016 1:25 PM, trader_4 wrote:

What is he driving? Could be a '62 Chevy with no auto tensioner.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

troubleshoot it?

headlights on. Then I cleaned all the connections in the starting systems from battery terminal to hot connections and grounds, and the problem stopped.

store. Then when I started, the battery needle start oscillating from 50% to 100% regularly, and the battery warning light started blinking off and on.

about 1/2 mile the oscillating and flashing stopped.

attention-getter, and not the actual reading.

I'll try to take a look at this weekend post what I find out if anything. But if I find a nice BBQ on sale, all bets are off.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
in message

troubleshoot it?

headlights on. Then I cleaned all the connections in the starting systems from battery terminal to hot connections and grounds, and the problem stopped.

store. Then when I started, the battery needle start oscillating from 50% to 100% regularly, and the battery warning light started blinking off and on.

about 1/2 mile the oscillating and flashing stopped.

attention-getter, and not the actual reading.

I'll try to take a look at this weekend post what I find out if anything. But if I find a nice BBQ on sale, all bets are off.
--

Still trying to find the time. I was able to catch it cycling just
now. No time to check at the alternator tonight, but here's some
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, May 28, 2016 at 11:25:53 PM UTC-4, Snuffy "Hub Cap" McKinney w rote:

oot it?

n. Then I cleaned all the connections in the starting systems from batter y terminal to hot connections and grounds, and the problem stopped.

re. Then when I started, the battery needle start oscillating from 50% to 100% regularly, and the battery warning light started blinking off and on.

/2 mile the oscillating and flashing stopped.

r, and not the actual reading.

e battery terminal.... Turn signals seems to cause the cycling tonight, alt hough I have seen it cycling with just the lights on.

You sure your meter isn't busted? Fully charged battery is just 12.7V

Those look like they are about 1V high too. I suspect your meter is off. You could try a fresh 9V battery to check, that should be around 9 .5V.
Assuming the meter is off, I don't see anything unusual in your readings. It's not dropping anywhere that would indicate a charging problem that would put the dash light on. Exactly what puts the light on varies from car to car. Some use the old method, where it's essentially a light bulb tied to 12V on one end, the other goes to the alternator. If the voltage there drops low, the bulb lights up. Others now have the computer monitoring the voltage at the alternator and it decides when to turn the light on.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.