Trying to assess if the MR2's battery is dead...or its the alternator (god I hope not)

Can anyone suggest which one to get please? The battery is a 12V one. I know I need a DC

ta

Probably the alternator. Have you stuck it on a trickle charge over night, then it's still gone dead?

get em from Halfords. If you can get the MR2 jump started then you can run it for an hour to recharge and then try it from there but if it keeps doing it everyday then the battery isnt holding the charge. It may show 12v but can still be goosed

To be honest unless you want something decent then most of the cheaper end of the range are as good as each other.

 

Something like this would be fine for most people: http://cgi.ebay.co.uk/DIGITAL-MULTIMETER-TESTER-CONTINUITY-BUZZER-19-RANGES-/180664919627?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2a1077e64b

 

If you wanted something decent then look around for a second hand Fluke meter like this: http://cgi.ebay.co.uk/Fluke-87-III-Mk3-True-RMS-Multimeter-/160599122752?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2564742340

 

HTH :)

Probably the alternator. Have you stuck it on a trickle charge over night, then it's still gone dead?

 

Charged it overnight, gonna bung it back in later but it died on Friday when Marc was on the way to work....

get em from Halfords. If you can get the MR2 jump started then you can run it for an hour to recharge and then try it from there but if it keeps doing it everyday then the battery isnt holding the charge. It may show 12v but can still be goosed

 

Cheers Marty, will jump start the two (again) and take it round to Halfrauds and see how it goes. Got it home Friday night after Marc broke down and I jump started it then, but the battery doesn't seem to be holding its charge - just need a multimeter to actually check before shelling out for a new one, just in case its not actually the battery....

If you can get the MR2 jump started then you can run it for an hour to recharge and then try it from there but if it keeps doing it everyday then the battery isnt holding the charge. It may show 12v but can still be goosed

 

That's not always a fair assessment with modern batteries. They tend to have memory and will only charge to their last charged point, when done by an alternator.

 

Trickle chargers that take 12 - 24 hours exist for a reason, and that's to fully charge the battery to it's capacity, the alternator will not do that, and certainly not in an hour. Easiest way to tell if a battery is foobarred, is to trickle charge it over night, then see how long it takes to die, if it dies almost immediately, the battery isn't holding charge, if it takes a day or more, then it's most likely the alternator.

To be honest unless you want something decent then most of the cheaper end of the range are as good as each other.

 

Something like this would be fine for most people: http://cgi.ebay.co.uk/DIGITAL-MULTIMETER-TESTER-CONTINUITY-BUZZER-19-RANGES-/180664919627?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2a1077e64b

 

If you wanted something decent then look around for a second hand Fluke meter like this: http://cgi.ebay.co.uk/Fluke-87-III-Mk3-True-RMS-Multimeter-/160599122752?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2564742340

 

HTH :)

 

Thanks

Think thats a 10V one and I need a 12V one but I'll look in tinternet for something that I can buy locally today if poss

Cheers

J

That's not always a fair assessment with modern batteries. They tend to have memory and will only charge to their last charged point, when done by an alternator.

 

Trickle chargers that take 12 - 24 hours exist for a reason, and that's to fully charge the battery to it's capacity, the alternator will not do that, and certainly not in an hour. Easiest way to tell if a battery is foobarred, is to trickle charge it over night, then see how long it takes to die, if it dies almost immediately, the battery isn't holding charge, if it takes a day or more, then it's most likely the alternator.

 

Its a MR2 not a modern day car so im pretty sure it wont have a modern day battery on and even so i have done this many of times with my extensive mechanical knowledge and it works. As long as the battery hasnt dropped under 9v it will be ok to charge it back up again and in an hour you can tell this. Of course multimeter is the way to go to see the charging voltage which will determine both questions but rather than shell out for one straight away there is a couple of steps to take.

Yeah by modern I meant the last ten years or so, my car's a 1990 but that's not when the battery was made. but Meh.

Thanks

Think thats a 10V one and I need a 12V one but I'll look in tinternet for something that I can buy locally today if poss

Cheers

J

 

Which one? You looking at the top one?

 

Look at the DCV range, you would select 20V which would give readings from 0-20V for testing :)

trickle chargers exist cos there cheap LOL!

 

I have just bought a charger at work that was just over a grand! A good battery charger will put as much amps in as possible to start with then tail off to a trickle charge at the end.

Get it running, take it to your lacal garage and ask them to do a drop test on thr battery. That will tell you if its your alternator or your battery.

Get it running, take it to your lacal garage and ask them to do a drop test on thr battery. That will tell you if its your alternator or your battery.

 

Dont forget it could also be a drain when the car is switched off (or even wiring issues) ;)

Dont forget it could also be a drain when the car is switched off (or even wiring issues) ;)

 

Very possibly it could be. But if you disconnect the battery then a drop test would check the battery.

Thanks

Think thats a 10V one and I need a 12V one but I'll look in tinternet for something that I can buy locally today if poss

Cheers

J

 

you dont get specific voltage multimeters, they cover massive ranges. The one in the ebay link for example measures up to 600v !

 

You just set it in the range you want it in on the dial.

 

Any multimeter will do. If you want to purchase local then Halfords, Argos, B&Q ...etc any will do the job.

Get it running, take it to your lacal garage and ask them to do a drop test on thr battery. That will tell you if its your alternator or your battery.

 

Ha, can't jump start it, its nose first in my garage, battery in the frunk, and my polo is on the drive - about 6 metres between the batteries lol and funnily enough my jump leads aren't big enough. Oh and I have a steep driveway so pushing it out the garage is gonna be a total tw@t lol. Battery seems ok, really do think its the alternator, which is a bit of a pisser :sad:

A mate has a spare one from a Rev 4, ours is a Rev 2, not sure if it'll have the right connector. Argh, bloody cars!!!