MR2 Owners Club • Dead battery?
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Dead battery?

Posted: 17/05/19 20:34
by Aerotus
Hey guys,

My remote key (both of them) had no effect on opening or locking the car. When i physically unlocked it and turned the key in the ignition, there was zero response from the car. No lights no sounds.

Is this a dead battery? The previous owner replaced the battery about 2 years ago. I drive it every 3 or 4 days for a bit and the weather is mild.

Any advice on what to do? Thanks!

Aero

Re: Dead battery?

Posted: 17/05/19 23:09
by peteV6R5
charge battery and see if it holds.
if yes nps just get smart charger
if no replace with as high a Ahr one that fits.

standard one on my mk2 was ok in 3sge but only lasted a week max when conveted to v6... now have 550CCA 65Ahr one and it lasts 2-3 weeks before needing charge if standing

Re: Dead battery?

Posted: 17/05/19 23:58
by Aerotus
I will buy a charger from screwfix tomorrow. How often do people charge their batteries and what usually triggers you to do so if it isnt already flat? Do you just buy a new battery every few years? Thanks

Aero

Re: Dead battery?

Posted: 18/05/19 7:41
by delhusband
Don't know if this helps any, but on a couple of occasions I've left the lights on after stopping the car, left the car for 40 minutes, and then the battery has lost charge to the point where the car won't start. But, when I turned the ignition there was a rapid fire clicking sound. Point I'm making its there was a noise.

Re: Dead battery?

Posted: 18/05/19 15:39
by Aerotus
Yes Del. My ignition made no noise at all. When i connected the charger just now it says battery is already full charged. That can't be right? Wouldnt it charge for at least an hour or so before saying that? It was last recharged by the owner in Jan!
I'm thinking maybe the problem is something else like a blown fuse? But then a fuse should only impact one system not everything? I'm confused.

Aero

Re: Dead battery?

Posted: 18/05/19 16:02
by peteV6R5
https://www.flickr.com/photos/112804433 ... 590838186/

check this out, sounds like main fusible link blown....be careful as need to find out why before just changing it.

bgb might help as well
https://www.mr2oc.co.uk/know-your-2.htm ... bartid=129

Re: Dead battery?

Posted: 18/05/19 18:46
by martin42006
Worth pointing out that the battery is totally dead then it could take a while before it will start to take a charge. The charger doesn't measure how full the battery is, it measures how much current the battery is drawing.
if everything was working fine before then i would bet on a flat bettery

Re: Dead battery?

Posted: 18/05/19 19:05
by Aerotus
Problem solved!

I took the battery to Halfords and he tested it. Was knackered and only producing 3V. It needs 12V to start the car. He said battery was totally dead meaning it could not be recharged. That's why my charger wasn't working properly in it.

Previous owner didnt drive it much hence the battery had degraded a lot despite being charged last Jan. I bought a bigger battery with 5 yr guarantee.

He said for the old battery doing short drives at low speeds wouldnt be charging the battery through the alternator. So i need to charge the battery more often and also take off the -ve node when I'm not using it for longer spells to prevent battery discharging. However, I'm thinking that would also stop my alarm from functioning so I wont be doing that.

Del he said if theres a clicking noise when turning ignition it means the starter motor has a problem.

So now i know a lot more about batteries I will make sure I do the appropriate maintenance.
Thanks guys.

Aero

Re: Dead battery?

Posted: 18/05/19 20:56
by jimi
Aerotus wrote: 18/05/19 19:05 Del he said if theres a clicking noise when turning ignition it means the starter motor has a problem.
That's not accurate, a flat battery can cause the clicking, depending on how flat it is. It's caused by the starter solenoid engaging but because there's not enough power to turn the engine over, the battery voltages drops and the solenoid disengages, battery voltage recovers and the solenoid engages again and so on ;) doesn'tnnecessarily mean there's any problem with the starter.
If you drive more than 30 miles every week or so it should be enough to keep a good battery charged.

Re: Dead battery?

Posted: 09/06/19 22:03
by Aerotus
When I remove the negative node from the car battery in order to prevent discharge over long periods of no use, the car alarm kicks off as it probably should. But then I end up reconnecting it to turn off the alarm! So how are you supposed to do this without triggering alarm? Thanks

Aero

Re: Dead battery?

Posted: 09/06/19 22:32
by Topdownman
Are you disconnecting the battery with the car unlocked and the alarm not set? If so, it shouldnt be going off.

Re: Dead battery?

Posted: 10/06/19 7:07
by Aerotus
Topdownman wrote: 09/06/19 22:32 Are you disconnecting the battery with the car unlocked and the alarm not set? If so, it shouldnt be going off.
Ah. Well if that is how it's done I wouldnt want to leave my car outside unlocked just for the sake of not discharging the battery. Safety comes first! Thanks

Aero

Re: Dead battery?

Posted: 10/06/19 13:46
by Topdownman
After disconnecting the battery you have to lock the passenger door from inside then lock the drivers door from outside with the key.

Re: Dead battery?

Posted: 11/06/19 13:47
by Aerotus
Topdownman wrote: 10/06/19 13:46 After disconnecting the battery you have to lock the passenger door from inside then lock the drivers door from outside with the key.
Thanks that makes sense