9V USB adapters flattening battery?

I have 2 9v USB adapters in my Defender 90 which have been working fine for a year or so.

The other day I plugged in two USB adapters and today my 90 refused to fire up. Stereo comes on and the battery and oil lights light up which suggests my battery's charge is low and leaving the USB adapters in is the likely explanation.

Is this even possible?

I'm confused by the fact that when I switch the engine off, the lights on the adapters also go off, suggesting they're switched off too. Is it possible that they've been slowing draining my battery over the last couple of nights and today was the last straw, or is it just coincidence and likely to be a faulty alternator?

its not the adaptors

HairyArse said:

....Stereo comes on and the battery and oil light up which suggests my battery's charge is low and leaving the USB adapters in is the likely explanation.

Click to expand...

How do you come to that conclusion? Do the dash lights and/or headlights dim when you try to start? If not then its not the battery

Engine model might help as well

the_wolf said:

How do you come to that conclusion? Do the dash lights and/or headlights dim when you try to start? If not then its not the battery

Click to expand...

Well the ignition isn't even trying to fire which suggested to me low battery charge as in my experience when a battery's charge gets to a certain point often there's enough to still power the stereo and dash lights but not enough to actually fire the ignition.

I'd just been out in it ten minutes previous without any bother and drove to work this morning just fine, too.

I've had a faulty alternator/battery in the past on previous Defenders and experienced these symptoms.

So it doesn't turn over. Does it make a clicking noise at all? Does anything happen?

the_wolf said:

Engine model might help as well

Click to expand...

95 plate 300 TDi I think.

the_wolf said:

So it doesn't turn over. Does it make a clicking noise at all? Does anything happen?

Click to expand...

Nothing at all.

bad wiring
dead starter
barrel faulty
aftermarket imob fault

You think? . Doesn't fill me full of confidence.

So it starts and drives fine sometimes but others it won't? Not sure on the 300tdi but if the starter motor is the same as a 200tdi then there's a small cable attached to a spade connector on the rear of it. If this is disconnected it gives the symptoms you have I.e. absolutely nothing happens when you try to start. The wire could be chafing or it could be wriggling loose sometimes

the_wolf said:

You think? . Doesn't fill me full of confidence.

So it starts and drives fine sometimes but others it won't? Not sure on the 300tdi but if the starter motor is the same then there's a small cable attached to a spade connector on the rear of it. If this is disconnected it gives the symptoms you have I.e. absolutely nothing happens when you try to start. The wire could be chafing or it could be wriggling loose sometimes

Click to expand...

It's not that it starts sometimes. This is literally the first time this has happened on this Defender. It's now stuck on my drive at home. Will try and charge the battery a bit tonight though I'm not sure the girlfriend's Suzuki Alto will prove to be fit for purpose.

If the lights don't dim when you try to start it then the battery should be fine but get a multimeter or a trickle charger (if you've got a good one with an lcd display) on it to check voltage anyway. If it just failed to start one day then its possible that the wire I mentioned has just popped off the back of the starter as even with a very flat battery it'll still turn over very slowly or at the very least you'll hear a clicking sound

Excellent. Will try that tonight. Is that starter wire easy to spot and re-attach for a beginner?

It's the only one on the back that attaches to a spade connector so it should be. Bear in mind I'm going off a 200tdi but someone might be able to clarify if 300s are the same or not

yes they are...
check the back of the ignition switch too, the spades like to come off there too on occasion.

although they are easier to feel than see, its behind the turbo, on the engine side of the solenoid IIRC. the main power cable gets in the way of a visual.

If its fitted with a factory alarm then the immobiliser bit can cause these symptoms. Look in the battery bay, is there a square box (about 6 inches square) fitted to the front facing panel? If there is give it a thump with your hand and try starting again. if that temporarily cures the fault then report back and I will tell you how to fix it.