What would drain the battery ?

Xantia2.0 · Post by **Xantia2.0** » 26 Sep 2010, 20:16

After about 3 weeks of flawless Citroen-ing I went out to the car this evening and was greeted firstly by no central locking and then by a clicking from the starter motor! The battery is practically new so I'm sure it isn't just the battery. The headlamps, interior lights etc... aren't staying on, so what could be draining the battery ? I'll jump-start the car tomorrow and let the alternator charge it back up but I don't want to be in the same situation again!

spider · Post by **spider** » 26 Sep 2010, 20:29

It is possible to get a new faulty battery, fortunately not often but it is known (infact the battery before the last one I got was faulty, would go flat (even when disconnected and fully charged externally) in about a week.

Various causes:

Faulty battery (internal short / dead cell)

Current drain (alternator internal fault, rectifier diodes go short so in effect the battery is powering the alternator coil) , fortunately rare

Current drain (various causes from stereo's to ECU relays sticking on)

Faulty alternator (its rare but I've seen one that would only charge at about 2amps or so, no other faults appeared so without an ammeter (induction type recommended) it appeared OK

Less common something like the boot / hatch light staying on all the time (as its not easily noticed)

addo · Post by **addo** » 26 Sep 2010, 21:02

It's more likely the alternator is shot. Valeo brushes and slip rings seem to wear faster than others!

Once it's running, check the charging voltage at 2500RPM and almost everything running - aircon, heater, blower on full, high beams, foglights, demister, radio, etc etc. With a reliable meter expect to see 13½-14½ volts across the battery terminals. If not, check between the positive terminal and cylinder head in case the battery ground is dodgy.

Xantia2.0 · Post by **Xantia2.0** » 26 Sep 2010, 21:16

Don't say that addo!! By "Valeo" do you mean the company that makes a lot of components for Rovers ? Just wondering!

I'll check the voltage tomorrow. If it is the alternator I will know my luck is BAD! As my Porsche 928's alternator just died a few days ago!

Xantia2.0 · Post by **Xantia2.0** » 27 Sep 2010, 07:43

Started it up and checked. It is running at 10Volts. After my mechanic buddy confirming it, it is the alternator

.

However! A new one is on order and should be here in a few hours!

addo · Post by **addo** » 27 Sep 2010, 09:50

OK, what kills them is (apart from brush wear) - hydraulic oil dripping from weepy O-ring seals on the pump above. There are three about 5/8" across, and three about 3/4" across.

Buy the seals from Citroën for only a couple of bob, and have your mate install them. Observe the order of small parts inside, and don't overtighten.

Xantia2.0 · Post by **Xantia2.0** » 27 Sep 2010, 10:42

I'll get that done! Thanks.