Battery not charging.

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Khoc
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Battery not charging.

Post by Khoc »

Put on all external lights as engine was running to check them and battery lost power.
I know there are 2 fuses in the front. The 7.5 I checked and is ok. The bigger fuse not sure how to take out, can it just be pulled out? Is there a 3rd fuse. As you can see from photos the battery stay around 12v and does not go any higher to suggest its being charged by alternator. If I was to try and put the multimeter up to the alternator (tight squeeze) if it was working okay would I see 12v with the engine off? This is the last job "hopefully" before I take it for a mot. Help appreciated :confused1: :confused1:
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jimi
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Re: Battery not charging.

Post by jimi »

Try the checks in this article to test the alternator https://www.mr2oc.co.uk/know-your2/mk2/ ... ad-on.html
MK2'svare prone to alternator wiring problems, depending on the test results this article may also help https://www.mr2oc.co.uk/know-your2/mk2/ ... epair.html
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Khoc
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Re: Battery not charging.

Post by Khoc »

Thanks Jim. Do you think its more likely it could be a fault in the loom? If I can get to the 3 pin plug then I will test each one. Other than that I was thinking of taking alternator out and repairing it.
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Re: Battery not charging.

Post by jeff »

i would suggest doing the above checks otherwise you're just guessing as to whether its a faulty loom
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Re: Battery not charging.

Post by jimi »

As Jeff says, the point of the tests is to find out if it's a wiring fault or alternator fault, without the tests your just guessing. Follow the article exactly, post up the results if your not sure how to interpret them.
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Re: Battery not charging.

Post by Khoc »

Can see a little bit of corrosion at the bottom of alternator on 2 bolts.
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Re: Battery not charging.

Post by jeff »

thats great, but what was the results of the tests ?
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Khoc
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Re: Battery not charging.

Post by Khoc »

All fuses are good. Main bolt going into alternator as good, over 12v. Tried from underneath to get 3 pin plug out but it's just out of reach. Now trying from above but can't get a good grip on it to remove it!! Taking a little brake then will try again. Was thinking if I can't then remove the alternator!

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Khoc
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Re: Battery not charging.

Post by Khoc »

Got the 3 pin plug off. Now it won't sit back in snug! Is it meant to click into place?
Get over 12v from each pin.
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Re: Battery not charging.

Post by jimi »

If your getting full battery voltage at the pins it would indicate a possible alternator problem. Don't remember the plug clicking in place but they are usually tight.
What condition is the battery in ? How old is it ?
That white deposit looks like waterproof grease, if it's soft and wipes off that's what it will be quite common electrical connectors in MR2 engine bays
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Khoc
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Re: Battery not charging.

Post by Khoc »

Battery is new. In the process of removing the main bolt holding the alternator to the bracket but limited space to do it. Gave a spray with wd40! Hopefully will help to loosen the bolt. Want to repair alternator myself.
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Re: Battery not charging.

Post by MR2DI4 »

You should find a pretty big write up on here on how to repair it yourself.

The main thing besides the bearings and brushes is to replace the Diode pack.
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Re: Battery not charging.

Post by Voivod »

Khoc wrote: 03/05/21 12:34 All fuses are good. Main bolt going into alternator as good, over 12v.
That's not good it should be 14v plus when car running..12v means faulty alternator or voltage regulator.
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Re: Battery not charging.

Post by jimi »

The 12v was with the engine off, he was following a test procedure to try and eliminate either the alt or the wiring ;)
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