1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air conditioning,
156k miles, here.

Voltage at the battery terminals when the car is
-- idling = about 12.7 volts
-- stopped, ignition off, also about 12.7 volts

In February, these numbers were 14.5 volts and 12. 4 volts.

Internet sources say a voltage when the car is idling of around 14 volts or so
indicates a properly operating charging system. So something is wrong, IMO.

I put in a new battery (Interstate) today, replacing the old one (4-years-old;
Diehard; wrong climate design as I moved from up North to the Southwest in the
past year?). The voltages above didn't change.

The car is on its second alternator (OEM). This 2nd alternator is 5 years and
50k miles old.

I installed a new alternator belt in June. I originally had the belt too loose,
as indicated by a squeal at cold startup. I tightened it and the squeal stopped.
Unfortunately I did not at this time check the battery terminal voltage.

I did shake out quite a lot of white powder (indicating some corrosion) from the
battery's positive terminal's cable connector while changing the batteries.

I'm going to do the checks at
http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.

Meanwhile, has anyone seen a condition like this? If so, what was the fix?

I think this is not critical unless I do a lot of driving with the lights on
(which I do not, as I drive mostly during daylight hours). But I do feel my
battery isn't going to be maintained at optimal charge and so, as winter
approaches, I need to fix this.

 

does the voltage drop under load? you know, fans, lights, defrost etc.,
on? if it drops to say 10V, then you have a charging problem. if not,
and it kicks up to 13/14V when loaded, everything's working just fine.

the alternator should have a regulator circuit that determines whether
it needs to "charge hard" or not. if the battery is charged and there's
minimal load, the alternator is not required to produce max output, and
indeed it shouldn't in order to not fry the battery.

alternators generally fail when the diodes go. semiconductors have a
limited lifetime at high temperatures, and hot climates and/or full
electrical loads will keep them nice & toasty. oem alternators can last
a good long time when treated conservatively.

Caroline wrote:
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air conditioning,
> 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14 volts or so
> indicates a properly operating charging system. So something is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one (4-years-old;
> Diehard; wrong climate design as I moved from up North to the Southwest in the
> past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5 years and
> 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too loose,
> as indicated by a squeal at cold startup. I tightened it and the squeal stopped.
> Unfortunately I did not at this time check the battery terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion) from the
> battery's positive terminal's cable connector while changing the batteries.
>
> I'm going to do the checks at
> http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
>
> Meanwhile, has anyone seen a condition like this? If so, what was the fix?
>
> I think this is not critical unless I do a lot of driving with the lights on
> (which I do not, as I drive mostly during daylight hours). But I do feel my
> battery isn't going to be maintained at optimal charge and so, as winter
> approaches, I need to fix this.
>
>

 

does the voltage drop under load? you know, fans, lights, defrost etc.,
on? if it drops to say 10V, then you have a charging problem. if not,
and it kicks up to 13/14V when loaded, everything's working just fine.

the alternator should have a regulator circuit that determines whether
it needs to "charge hard" or not. if the battery is charged and there's
minimal load, the alternator is not required to produce max output, and
indeed it shouldn't in order to not fry the battery.

alternators generally fail when the diodes go. semiconductors have a
limited lifetime at high temperatures, and hot climates and/or full
electrical loads will keep them nice & toasty. oem alternators can last
a good long time when treated conservatively.

Caroline wrote:
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air conditioning,
> 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14 volts or so
> indicates a properly operating charging system. So something is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one (4-years-old;
> Diehard; wrong climate design as I moved from up North to the Southwest in the
> past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5 years and
> 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too loose,
> as indicated by a squeal at cold startup. I tightened it and the squeal stopped.
> Unfortunately I did not at this time check the battery terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion) from the
> battery's positive terminal's cable connector while changing the batteries.
>
> I'm going to do the checks at
> http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
>
> Meanwhile, has anyone seen a condition like this? If so, what was the fix?
>
> I think this is not critical unless I do a lot of driving with the lights on
> (which I do not, as I drive mostly during daylight hours). But I do feel my
> battery isn't going to be maintained at optimal charge and so, as winter
> approaches, I need to fix this.
>
>

 

Caroline wrote:
>
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air
> conditioning, 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14
> volts or so indicates a properly operating charging system. So something
> is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one
> (4-years-old; Diehard; wrong climate design as I moved from up North
> to the Southwest in the past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5
> years and 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too
> loose, as indicated by a squeal at cold startup. I tightened it and the
> squeal stopped. Unfortunately I did not at this time check the battery
> terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion)
> from the battery's positive terminal's cable connector while changing the
> batteries.

If my memory serves me correctly, you may want to check the battery cables
for a voltage drop. Can you measure a large voltage drop (high resistance),
i.e., more than 0.3-0.5V, across the battery cable? If so, then it may need
to be replaced.

Note: To measure a voltage drop connect the + lead of your DVOM to the +
battery terminal and the - DVOM lead to the other end of the wire at its
connector.

Eric

 

Caroline wrote:
>
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air
> conditioning, 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14
> volts or so indicates a properly operating charging system. So something
> is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one
> (4-years-old; Diehard; wrong climate design as I moved from up North
> to the Southwest in the past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5
> years and 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too
> loose, as indicated by a squeal at cold startup. I tightened it and the
> squeal stopped. Unfortunately I did not at this time check the battery
> terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion)
> from the battery's positive terminal's cable connector while changing the
> batteries.

If my memory serves me correctly, you may want to check the battery cables
for a voltage drop. Can you measure a large voltage drop (high resistance),
i.e., more than 0.3-0.5V, across the battery cable? If so, then it may need
to be replaced.

Note: To measure a voltage drop connect the + lead of your DVOM to the +
battery terminal and the - DVOM lead to the other end of the wire at its
connector.

Eric

 

On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline" <caroline10027remove@earthlink.net>
wrote:

||1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air
conditioning,
||156k miles, here.
||
||Voltage at the battery terminals when the car is
||-- idling = about 12.7 volts
||-- stopped, ignition off, also about 12.7 volts
||
||In February, these numbers were 14.5 volts and 12. 4 volts.
||
||Internet sources say a voltage when the car is idling of around 14 volts or so
||indicates a properly operating charging system. So something is wrong, IMO.
||
||I put in a new battery (Interstate) today, replacing the old one (4-years-old;
||Diehard; wrong climate design as I moved from up North to the Southwest in the
||past year?). The voltages above didn't change.
||
||The car is on its second alternator (OEM). This 2nd alternator is 5 years and
||50k miles old.
||
||I installed a new alternator belt in June. I originally had the belt too
loose,
||as indicated by a squeal at cold startup. I tightened it and the squeal
stopped.
||Unfortunately I did not at this time check the battery terminal voltage.
||
||I did shake out quite a lot of white powder (indicating some corrosion) from
the
||battery's positive terminal's cable connector while changing the batteries.
||
||I'm going to do the checks at
||http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
||
||Meanwhile, has anyone seen a condition like this? If so, what was the fix?
||
||I think this is not critical unless I do a lot of driving with the lights on
||(which I do not, as I drive mostly during daylight hours). But I do feel my
||battery isn't going to be maintained at optimal charge and so, as winter
||approaches, I need to fix this.

Caroline
If your boltage reads 12.7 with motor off, motor on, and motor revved up a
little, then you alternator is toast. 13.2V is a bare minimum and it should have
that at idle of just above. 12.7 means a fully charged battery.

Texas Parts Guy

 

On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline" <caroline10027remove@earthlink.net>
wrote:

||1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air
conditioning,
||156k miles, here.
||
||Voltage at the battery terminals when the car is
||-- idling = about 12.7 volts
||-- stopped, ignition off, also about 12.7 volts
||
||In February, these numbers were 14.5 volts and 12. 4 volts.
||
||Internet sources say a voltage when the car is idling of around 14 volts or so
||indicates a properly operating charging system. So something is wrong, IMO.
||
||I put in a new battery (Interstate) today, replacing the old one (4-years-old;
||Diehard; wrong climate design as I moved from up North to the Southwest in the
||past year?). The voltages above didn't change.
||
||The car is on its second alternator (OEM). This 2nd alternator is 5 years and
||50k miles old.
||
||I installed a new alternator belt in June. I originally had the belt too
loose,
||as indicated by a squeal at cold startup. I tightened it and the squeal
stopped.
||Unfortunately I did not at this time check the battery terminal voltage.
||
||I did shake out quite a lot of white powder (indicating some corrosion) from
the
||battery's positive terminal's cable connector while changing the batteries.
||
||I'm going to do the checks at
||http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
||
||Meanwhile, has anyone seen a condition like this? If so, what was the fix?
||
||I think this is not critical unless I do a lot of driving with the lights on
||(which I do not, as I drive mostly during daylight hours). But I do feel my
||battery isn't going to be maintained at optimal charge and so, as winter
||approaches, I need to fix this.

Caroline
If your boltage reads 12.7 with motor off, motor on, and motor revved up a
little, then you alternator is toast. 13.2V is a bare minimum and it should have
that at idle of just above. 12.7 means a fully charged battery.

Texas Parts Guy

 

Caroline wrote:
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air conditioning,
> 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14 volts or so
> indicates a properly operating charging system. So something is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one (4-years-old;
> Diehard; wrong climate design as I moved from up North to the Southwest in the
> past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5 years and
> 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too loose,
> as indicated by a squeal at cold startup. I tightened it and the squeal stopped.
> Unfortunately I did not at this time check the battery terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion) from the
> battery's positive terminal's cable connector while changing the batteries.
>
> I'm going to do the checks at
> http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
>
> Meanwhile, has anyone seen a condition like this? If so, what was the fix?
>
> I think this is not critical unless I do a lot of driving with the lights on
> (which I do not, as I drive mostly during daylight hours). But I do feel my
> battery isn't going to be maintained at optimal charge and so, as winter
> approaches, I need to fix this.
>
>
hi caroline
If the idle voltage is the same as the no load voltage,i.e. car
stopped,it looks as if the alternator is not putting out any
charge...another recon needed??
hope this helps
spike

 

Caroline wrote:
> 1991 Civic LX 4-door sedan, 1.5 Liter, manual transmission, no air conditioning,
> 156k miles, here.
>
> Voltage at the battery terminals when the car is
> -- idling = about 12.7 volts
> -- stopped, ignition off, also about 12.7 volts
>
> In February, these numbers were 14.5 volts and 12. 4 volts.
>
> Internet sources say a voltage when the car is idling of around 14 volts or so
> indicates a properly operating charging system. So something is wrong, IMO.
>
> I put in a new battery (Interstate) today, replacing the old one (4-years-old;
> Diehard; wrong climate design as I moved from up North to the Southwest in the
> past year?). The voltages above didn't change.
>
> The car is on its second alternator (OEM). This 2nd alternator is 5 years and
> 50k miles old.
>
> I installed a new alternator belt in June. I originally had the belt too loose,
> as indicated by a squeal at cold startup. I tightened it and the squeal stopped.
> Unfortunately I did not at this time check the battery terminal voltage.
>
> I did shake out quite a lot of white powder (indicating some corrosion) from the
> battery's positive terminal's cable connector while changing the batteries.
>
> I'm going to do the checks at
> http://www.honda.co.uk/owner/Concert...k301/16-66.pdf this weekend.
>
> Meanwhile, has anyone seen a condition like this? If so, what was the fix?
>
> I think this is not critical unless I do a lot of driving with the lights on
> (which I do not, as I drive mostly during daylight hours). But I do feel my
> battery isn't going to be maintained at optimal charge and so, as winter
> approaches, I need to fix this.
>
>
hi caroline
If the idle voltage is the same as the no load voltage,i.e. car
stopped,it looks as if the alternator is not putting out any
charge...another recon needed??
hope this helps
spike

 

Rex B wrote:
> If your boltage reads 12.7 with motor off, motor on, and motor revved up a
> little, then you alternator is toast. 13.2V is a bare minimum and it should have
> that at idle of just above. 12.7 means a fully charged battery.

Do Honda's have voltage regulators? ISTR that a dead voltage regulator
could lead to the appearance of a dead alternator in 80s GM cars, but I
may be misremembering.

Abe

 

Rex B wrote:
> If your boltage reads 12.7 with motor off, motor on, and motor revved up a
> little, then you alternator is toast. 13.2V is a bare minimum and it should have
> that at idle of just above. 12.7 means a fully charged battery.

Do Honda's have voltage regulators? ISTR that a dead voltage regulator
could lead to the appearance of a dead alternator in 80s GM cars, but I
may be misremembering.

Abe

 

On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline"
<caroline10027remove@earthlink.net> wrote:

>I did shake out quite a lot of white powder (indicating some corrosion) from the
>battery's positive terminal's cable connector while changing the batteries.

Clean your battery cable clamps with a round wire brush. Check the
cable itself under the insulation near the clamp, make sure it isn't
corroded under there. Check both cable connections at the other end,
especially the ground cable. Unbolt them, clean with a file and
reconnect. Half an ohm resistance in a 115 volt circuit is nothing.
Half an ohm in a 12 volt battery cable is a big deal. Do the math
E = IR If the alternator wants to put 20 amps into the battery,
..5 X 20 = 10 volts drop.

 

On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline"
<caroline10027remove@earthlink.net> wrote:

>I did shake out quite a lot of white powder (indicating some corrosion) from the
>battery's positive terminal's cable connector while changing the batteries.

Clean your battery cable clamps with a round wire brush. Check the
cable itself under the insulation near the clamp, make sure it isn't
corroded under there. Check both cable connections at the other end,
especially the ground cable. Unbolt them, clean with a file and
reconnect. Half an ohm resistance in a 115 volt circuit is nothing.
Half an ohm in a 12 volt battery cable is a big deal. Do the math
E = IR If the alternator wants to put 20 amps into the battery,
..5 X 20 = 10 volts drop.

 

John Ings wrote:

> On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline"
> <caroline10027remove@earthlink.net> wrote:
>
>
>>I did shake out quite a lot of white powder (indicating some corrosion) from the
>>battery's positive terminal's cable connector while changing the batteries.
>
>
> Clean your battery cable clamps with a round wire brush. Check the
> cable itself under the insulation near the clamp, make sure it isn't
> corroded under there. Check both cable connections at the other end,
> especially the ground cable. Unbolt them, clean with a file and
> reconnect. Half an ohm resistance in a 115 volt circuit is nothing.
> Half an ohm in a 12 volt battery cable is a big deal. Do the math
> E = IR If the alternator wants to put 20 amps into the battery,
> .5 X 20 = 10 volts drop.

theyre worth replacing, regardless. along with the connection to the
alternator. if the readings still dont improve, its new rebuilt
alternator time.

 

John Ings wrote:

> On Tue, 07 Sep 2004 02:54:10 GMT, "Caroline"
> <caroline10027remove@earthlink.net> wrote:
>
>
>>I did shake out quite a lot of white powder (indicating some corrosion) from the
>>battery's positive terminal's cable connector while changing the batteries.
>
>
> Clean your battery cable clamps with a round wire brush. Check the
> cable itself under the insulation near the clamp, make sure it isn't
> corroded under there. Check both cable connections at the other end,
> especially the ground cable. Unbolt them, clean with a file and
> reconnect. Half an ohm resistance in a 115 volt circuit is nothing.
> Half an ohm in a 12 volt battery cable is a big deal. Do the math
> E = IR If the alternator wants to put 20 amps into the battery,
> .5 X 20 = 10 volts drop.

theyre worth replacing, regardless. along with the connection to the
alternator. if the readings still dont improve, its new rebuilt
alternator time.