Battery discharge

[muzza49]

I'm hoping that someone has an answer to my problem, with the battery discharging.
I seem to have an intermittent problem with the battery going flat overnight.
Also, I was out pottering around, with about 4 stops the other day. When I went to start the car, after the last stop, it wouldn't turn over.
Fortunately I bought a quick charge unit and so connected it up and away I went.
I've had the generator checked by 3 people, 2 said it's fine, the 3rd said not.
The ammeter is always showing that it is charging.
Any clues ???

[NigelW]

Have you had the battery checked with a discharge tester? It sounds like the battery has had it.

[Jose]

I would substitute the battery with a fully charged one and see if it discharges too, in which case the cause must be the Generator or Alternator.

Note that Generators do not charge while engine is idling.

[muzza49]

Bought a new lead plate battery, which I'm led to believe is suitable for cars with generators, unlike the new style batteries (not sure what they call them), one of which was fitted. It looks like, the genny was charging, but the battery was not accepting the charge - sounds weird, but all seems to be well again! - thanks for the feedback.

[NigelW]

Glad to hear all is now well. The modern batteries you are referring to are glass mat type, most often used with cars with stop/start systems. These cars have battery condition electronics in the ecu that monitors charge rate. I had one on my XF Jag that gave a few problems.