Rover 216 battery discharging

[Panic Button]

My mother-in-law's R reg Rover 216 is suffering a discharging battery.

I assumed the battery had failed, so fitted a new one. This one too is going flat quite quickly, but we can't find any lights left on. It is a convertible, so no heated rear window.

Does anyone know the most likely cause of this?

[lslowry]

could it be the light in the boot not switching off when the boot is shut? i have known this happen on other cars

[Panic Button]

Thanks, we thought it was that as the boot doesn't always shut.

However by dropping the back seat I have checked it goes off, and trained MOL to shut it properly and check the boot open light on the dash

[logic]

i had this problem a couple of years ago,( battery going totally flat overnight,) but it was an intermittent occurance,but bought new battery, same thing happened again,
In this instance it turned out to be a diode or something in the alternator,( I am not an electrical person, ) so a new alternator was fitted, no prob since.

[Panic Button]

Thanks Logic - I suspected it was a failed component, but had no idea which.

Sounds like a job for a professional, with bill to match.

[TWR]

Hi, It's best to check this when it's dark, start the car & look at the dash can you see a faint light coming from the Ign ( Red light the one you see when you first turn on the Ign) If so, Alternator. Does your glove compartment have a light? check this. also, has your cig lighter stuck inside the holder, this again will drain your system.

[Hymie]

Get hold of a multimeter, they can be purchased for less than £5, or borrow one.
Disconnect the battery negative lead and place the multimeter (on DC current) between the negative battery terminal and the car’s chassis (with the ignition off).

You should see the meter register the battery drain, which could be over 5 amps. Next, pull the fuses one at a time, when the battery drain current drops, you have identified the circuit drawing the current. Check the handbook for which electrical items are protected by the fuse (from its number), and unplug/disconnect the items in turn to discover the faulty component.

Since the ignition will be off – very few circuits will be powered. Logic may be correct in that it is the alternator diode pack. Unplug it and see if the current drops, otherwise you might be replacing a perfectly good alternator.

[Panic Button]

Thanks. Very useful advice from both of you.


I will let you know the result.

[Panic Button]

Rather than buy a multimeter, I just disconnected the battery then touched a bulb between the battry cable and terminal.

It lit up, then I tried it again as I removed fuses in turn.

It turns out the circuit that is running is the radio / interior light / clock circuit.

I suspect the CD changer in the boot, but am delaying further investigation until a day off without rain.

At least that is not as bad as an alternator.