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Battery Warning Light - LR 90 V8

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Geo

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May 9, 2013, 3:50:06 PM5/9/13
to
Hello everyone,

the battery warning light on my 90's dash always turns on when I start it
but turns off almost immediately afterwards. Well, it did. Now it just stays
on, its brightness varying:
- It's always on but very dim. Rev the engine over a point and it goes
erratic, continuously turning brighter, then dimmer. I'm assuming it has to
do with the spark plugs although I'm not sure (the frequency seems a bit
irregular/unstable)
- Use anything that needs electricity and it goes proportionately brighter -
accordingly, the battery voltage gauge drops to a bit below the middle mark
with the headlights on.


It's been like this for months without any problem to the vehicle's function
and it always starts with half a turn of the key. I don't remember the exact
values any more but I checked the voltage on the battery and it seems to be
fine with the engine off and charging properly (revving increases the
voltage up to a point) when running. The battery's own indicator suggests
it's ok. I put it on a CTEK charger a couple of times and it charged without
any issues.


So what say the wiser owners? What would cause the battery check to state
there's a problem when there doesn't appear to be one?


--
Geo

John Williamson

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May 9, 2013, 4:16:03 PM5/9/13
to
Geo wrote:
> Hello everyone,
>
> the battery warning light on my 90's dash always turns on when I start
> it but turns off almost immediately afterwards. Well, it did. Now it
> just stays on, its brightness varying:
> - It's always on but very dim. Rev the engine over a point and it goes
> erratic, continuously turning brighter, then dimmer. I'm assuming it has
> to do with the spark plugs although I'm not sure (the frequency seems a
> bit irregular/unstable)
> - Use anything that needs electricity and it goes proportionately
> brighter - accordingly, the battery voltage gauge drops to a bit below
> the middle mark with the headlights on.
>
Typical of a clapped out alternator. Probably worn brushes in the
alternator. Possibly a defective rectifier diode in the alternator.
Possibly the regulator. The cheapest repair is normally an exchange
alternator, and check the wiring before you fit the new one.

>
> It's been like this for months without any problem to the vehicle's
> function and it always starts with half a turn of the key. I don't
> remember the exact values any more but I checked the voltage on the
> battery and it seems to be fine with the engine off and charging
> properly (revving increases the voltage up to a point) when running. The
> battery's own indicator suggests it's ok. I put it on a CTEK charger a
> couple of times and it charged without any issues.
>
>
> So what say the wiser owners? What would cause the battery check to
> state there's a problem when there doesn't appear to be one?
>
>

The battery check is showing a problem because the alternator isn't
putting out enough current to keep the battery fully charged.

--
Tciao for Now!

John.

Geo

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May 10, 2013, 9:46:58 AM5/10/13
to
"John Williamson" wrote
> Geo wrote:
> > Hello everyone,
> >
> > the battery warning light on my 90's dash always turns on ...
>
> Typical of a clapped out alternator. Probably worn brushes in the
> alternator. Possibly a defective rectifier diode in the alternator.
> Possibly the regulator. The cheapest repair is normally an exchange
> alternator, and check the wiring before you fit the new one.
>
> > ...
>
> The battery check is showing a problem because the alternator isn't
> putting out enough current to keep the battery fully charged.

I thought about the alternator but I've been using the vehicle like that for
six months now (half of the time with the lights on) and I don't see any
evidence of a weakening battery. Perhaps there's still enough current to
fully cover my needs but not as much as a healthy alternator would produce?
Given that replacing the alternator isn't the cheapest of options and I
haven't been left stranded yet, I'll leave it until I get the vehicle
serviced in a month or two... or until I am left stranded.

Thank you for your answer.

--
Geo

hctbn

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May 10, 2013, 9:01:53 PM5/10/13
to
> the battery warning light on my 90's dash always turns on when I start it
>
> but turns off almost immediately afterwards. Well, it did. Now it just stays
>
> on, its brightness varying:
>
> - It's always on but very dim. Rev the engine over a point and it goes
>
> erratic, continuously turning brighter, then dimmer.

Long time since I've been on this fine group, but I agree that it's a knackered alternator - mine did the same for quite a while while the battery very slowly went down (over many weeks), it died when we finally got to winter. If you're not totally reliant then I'd stick with it and just keep a weather eye on the battery, and perhaps keep a watch on the forums for a replacement.

Bob

1990 ex-RAF 110 3.5 V8 17KJ83
1967 3/4 ton Sankey 09ES17

SpamTrapSeeSig

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May 11, 2013, 12:38:49 PM5/11/13
to
In article <327710ad-1d35-41ff...@googlegroups.com>,
hctbn <bob....@googlemail.com> writes
Bob's not wrong, but if you just leave it alone, you _will_ kill the
battery.
I'd top it up regularly, say once a week, with a charger. They should be
kept fully charged otherwise the battery degrades quite fast.

--
SimonM

Geo

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May 13, 2013, 1:38:50 PM5/13/13
to
"SpamTrapSeeSig" wrote
>hctbn <bob....@googlemail.com> writes
>
>>Long time since I've been on this fine group, but I agree that it's a
>>knackered alternator - mine did the same for quite a while while the
>>battery very slowly went down (over many weeks), it died when we finally
>>got to winter.
>
>Bob's not wrong, but if you just leave it alone, you _will_ kill the
>battery.
>I'd top it up regularly, say once a week, with a charger. They should be
>kept fully charged otherwise the battery degrades quite fast.

Bugger, I was hoping I'd get away with some easy (read: cheap) fix. I
suppose I'll have to schedule a replacement within reasonable time, in the
meantime I'll keep an eye on the battery and use my charger once in a while.
I guess 25 years and 125000 kms of service isn't too shabby for an
alternator...

Once again, thank you all for the answers.

--
Geo

Dave Baxter

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May 21, 2013, 9:24:43 AM5/21/13
to
In article <kmgule$h0q$1...@speranza.aioe.org>,
achRrEeMsOt...@hotmail.com says...
>
> Hello everyone,
>
> the battery warning light on my 90's dash always turns on when I start it
> but turns off almost immediately afterwards. Well, it did. Now it just stays
> on, its brightness varying:
<Snipped>

What age 90? Do you know what make/model of alternator is fitted, some
are *Much* easier to DIY fix than others. (The old Lucas ACR series in
particular are easy to fix.)

If the brushes are worn, don't leave it too long, or the slip rings too
will be damaged, and that can write off the whole thing. Unless you
have a stock of similar machines to canabalise.

Check too, for chafed wires relating to the warning light, loose
terminals and so on. TAKE CARE!!!! It is best to disconnect the
battery (-ve side) so if you short something by accident, you don't
start a fire and burn out your wiring loom.

If your 90 has any security gadgets, make sure you know the unlock code
(s) Same for the stereo etc (If you have that luxury!)

Using a good voltmeter (Digital preferably) measure the battery voltage
with the engine off (after an hour say.) It should be at least 12.4V
Much less than that, and either the battery is low, or on the way out.

Start up, and after a few minutes to recharge (give it the chance to
replenish the grunt needed to start the mill) it should be up to some
14V. Turn on the headlights, and anything else beefy you might have
(heated windows etc) the battery volts should stay at much the same with
the engine running, even at idle. (They might drop a little, plus a
hard working alternator at idle speed can make a bit of a whistle. If
it realy screams at you, you might have lost one winding/phase/diode
etc.)

Poke arround locally for a Truck Electrical specialist. Often, they can
repair alternators for very economic rates, usually for much less than
an exchange unit, unless something major has failed "big time". Even
then, they probably have something suitable at reasonable cost. (Truck
firms like low costs, and they dont like short term repairs either!)

The tiddly little things on LR's will be no problem for them. I've had
bearings replaced and all sorts over the years by one group in the UK,
always good service (fast and cheap!) And the repairs stay good too.

They also do starter and winch motors too....

Have Fun.

Dave B.

PS: Re ACR series alternators. They use the same bearings as
Armstrong MT series bike front wheels. But, the bearings on the bike
are sealed, those in the alteranator are not. Guess what I did one time
for someone, and that is still working despite several dunkings in
mudruns etc... :)

Austin Shackles

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Jun 10, 2013, 8:25:40 AM6/10/13
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On or around Thu, 9 May 2013 22:50:06 +0300, "Geo"
<achRrEeMsOt...@hotmail.com> enlightened us thusly:
The altenrator is semi-shagged. I did once know what causes this one, I
think it's one or more diodes in the rectifier going tits-up but don't quote
me...

I had one like this and as you say, it worked fine although eventually it
got worse. Chances are the output is just a bit low, which, in most use
scenarios, doesn't show. If you did a lot of short journeys in winter, it
might show as a gradual loss of charge.
--
This is a temporary signature, The regualr signature is not available
due to unresolved techincal issues. We are working to restore the
normal service, in the meantime we apologise for any inconvenience caused.
Austin.
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