Battery Low Warning

[AlanD]

Hi all,

Those who follow the Mondeo sub group will know I replaced the battery in the MA a few months ago.

Today while waiting for the GLW, who was getting some diagnostic tests done at Monash, and playing the radio with the keys out of the ignition, I got a "Low Battery" warning in the information display.

"Curses" I thought, "Just my luck to get a dud as a replacement"

But some tests when we got home indicated something was amiss. The battery was showing 11.75 volts with no charging, but 12.8V or so when being charged, which is insufficient to get a Lead Acid Battery to full charge. So I began to wonder about a faulty charging system. Got The GLW to start the car to check on the terminal voltage under maximum load and noticed some sparking in the region of the main body 0 Volts connection. (It's a bolt with an odd head shape adjacent to the battery shroud on the RHS as you look from the car's front).

Then I remembered that when the battery was being replaced the "guy" tried to undo this connection and I stopped him, pointing out that to do so would defeat the attachment of the backup battery. But a quick check showed that he had managed to loosen it slightly and it did not get tightened up, creating a higher than normal resistance through the join.

Application of a 13 mm spanner seems to have solved the problem. The charging system is now applying 14.1 to 14.2 volts to the battery and off load the battery is holding 12.8 volts. I'll keep an eye on things and report if the "fix" is a permanant one.

While this was going on I also noticed the headlamps flickering at idle and wondered why this was happening, as I had not noticed it previously. My guess is that under running conditions the vibration changed the connection resistance enough to cause this effect - I'll keep an eys on that as well.

Moral is - Pays to check electrical connections and make sure they are sound.

Cheers

[apstar]

Good points Alan lead acid batteries require 14.7 Volts from the alternator and can take as much current the battery can handle,where as NiCad are current regulated but don't care at what voltage,most problems are caused by OTHERS especially after a service as I cringe each time I put it in for service I always say "What have they left off"!!

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ps most battery chargers that people use to charge batteries are destroying the battery as the cheaper models are not DC regulated to produce a clean DC voltage they under load are producing AC on top of the DC as much as 2 volts AC and more onto the battery!!

[AlanD]

Update.

Hi all,

The fix seems to have solved the charging problem

Battery charged to 12.6 Volts, faster starting, no warnings, lights not flickering, and the engine seems to be running better, but this last might be that the air moisture content may be having an effect. I've noticed that, in all the cars we have owned, when it's wet the engines have operated with less vibration - and better fuel economy often. Always have wondered why manfacturers haven't noticed this and taken steps to moisturise the air if needed. Maybe the improvement is so small the extra equipment would be a buyer turn off as it would increase the vehicle cost.

I'm thankful that I noticed the warning and the problem got solved at home rather than having difficulties when remote from civilisation. Pays to check the tightness of that bolt and not let anyone fiddle with it.

Cheers

[apstar]

Originally Posted by AlanD

Update.

Always have wondered why manfacturers haven't noticed this and taken steps to moisturise the air if needed. Maybe the improvement is so small the extra equipment would be a buyer turn off as it would increase the vehicle cost.



Cheers

`

Thats why turbo diesels have intercoolers!!

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