Battery not charging

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P

Peter

Guest
Battery not charging, charge light extinguishes as soon as engine starts.
New battery fitted two months ago.
Checked voltage at battery.
11.9 volts engine stopped
Maximum of 13.2 volts engine revving
Alternator need servicing???


 
> Battery not charging, charge light extinguishes as soon as engine starts.
> New battery fitted two months ago.
> Checked voltage at battery.
> 11.9 volts engine stopped
> Maximum of 13.2 volts engine revving
> Alternator need servicing???


Voltages are a tad low, especially for a new battery. Sounds like a cell has
gone u/s to me.
I'd try another battery as it clearly is receiving a charging voltage. Might
be interesting to connect a mains charger and see what current you get. A
flat battery will draw quite a few amps, 3-5, a fully charged one will only
draw less than one.

If it is your alternator it can only be because it can deliver the volts but
maybe not enough current.

TonyB


 
In my experience it's more likely to be a poor engine earth strap. With
the engine running at a good fast idle check the voltage between the
battery earth terminal and the engine block. It should be less than 0.1
volts. If it isn't then remove the engine earth strap and clean all the
connections on the strap, the engine and the chassis/body. If it is
less than 0.1 volts then check the terminals on the back of the
alternator for corrosion. If these checks are all in order then it is
likely to be a dodgy diode pack in the alternator. Depending on the
cost of a recon alternator for your vehicle then it is often cheaper to
buy just the diode pack, although in some cases it isn't a simple
remove a few screws and connectors job so have a look first.

Phil

TonyB wrote:
>>Battery not charging, charge light extinguishes as soon as engine starts.
>>New battery fitted two months ago.
>>Checked voltage at battery.
>>11.9 volts engine stopped
>>Maximum of 13.2 volts engine revving
>>Alternator need servicing???

>
>
> Voltages are a tad low, especially for a new battery. Sounds like a cell has
> gone u/s to me.
> I'd try another battery as it clearly is receiving a charging voltage. Might
> be interesting to connect a mains charger and see what current you get. A
> flat battery will draw quite a few amps, 3-5, a fully charged one will only
> draw less than one.
>
> If it is your alternator it can only be because it can deliver the volts but
> maybe not enough current.
>
> TonyB
>
>

 
> >>Battery not charging, charge light extinguishes as soon as engine
starts.
> >>New battery fitted two months ago.
> >>Checked voltage at battery.
> >>11.9 volts engine stopped
> >>Maximum of 13.2 volts engine revving
> >>Alternator need servicing???


Those voltages do sound low - my Disco puts out about 13.9 volts when
running.

Fully charged battery should produce just under 2.1V per cell, so if you
charge the battery OUT of the car, you should end up with somewhere between
12.3 and 12.6 V. If you're not getting that, the battery is probably
faulty.

By charging out of the car, you will eliminate alternator problems and
earthing problems, so it will be a true test of the battery. If after that,
the battery is fine, I'd agree with other posters and look at earthing and
the alternator - as I said, 13.2 at teh alternator does seem very low.

Cheers!
Graham Carter

--
Carter Computer Services (Pvt) Ltd
P.O. Box A1619
Avondale
Harare
Zimbabwe
Tel: +263 4 300082
Cell: +263 91 329310
Fax: +263 918 329310
email:gcarter(at)mweb(dot)co(dot)zw



 
Thanks for all the info'.
I should have stated that the battery voltage of 11.9 was with it flat. Have
since recharged it and am running about on battery current and it is
starting well so I think the battery is OK. I'll go through the cleaning of
contacts and connections next.
Thanks again.


 

"Peter" <[email protected]> wrote in message
news:[email protected]...
> Thanks for all the info'.
> I should have stated that the battery voltage of 11.9 was with it flat.
> Have since recharged it and am running about on battery current and it is
> starting well so I think the battery is OK. I'll go through the cleaning
> of contacts and connections next.
> Thanks again.


Alternator should be regulating to somewhere between 13.8 and 14.4 volts
with engine running at idle. A good check for output current is to confirm
the voltage and monitor it whilst adding more electrical loads. Start with
the headlights on full beam, then add the heated rear window, then the
blower motor etc etc until you reach a loading where the voltage drops just
below 13.8. Now increase the rpm to around 1500ish and the volts ought to
rise back to somewhere over the lower figure of 13.8, unless you are
applying more load than the rated output.
Badger.


 
Thanks Badger,
I thought the voltage figures should be somewhere around yours. At present
the best I can do is 13.2 volts, not enough to overcome counter voltage.


 
On or around Mon, 23 Jan 2006 18:53:19 +0000 (UTC), "Badger"
<[email protected]> enlightened us thusly:

>
>"Peter" <[email protected]> wrote in message
>news:[email protected]...
>> Thanks for all the info'.
>> I should have stated that the battery voltage of 11.9 was with it flat.
>> Have since recharged it and am running about on battery current and it is
>> starting well so I think the battery is OK. I'll go through the cleaning
>> of contacts and connections next.
>> Thanks again.

>
>Alternator should be regulating to somewhere between 13.8 and 14.4 volts
>with engine running at idle.


with minimal electrical load, mind.

I trust you have got an "ignition" light when the engine's stopped. The
wire through the ignition light supplies the reference voltage to start it
charging. Disconnect it and no chargee. I suspect that on some systems you
get no chargee with a blown bulb...

--
Austin Shackles. www.ddol-las.net my opinions are just that
In Touch: Get in touch with yourself by touching yourself.
If somebody is watching, stop touching yourself.
from the Little Book of Complete B***ocks by Alistair Beaton.
 
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