renault master 2005 - Renault master will only charge at 12.5 volts?????

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Sat 27 Jun 2015 19:27
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

Hi, having problems with my 2005 master van , will only charge at 12.5 volts??? had new battery, had new alternator still sits at 12.5 volts, does the exciter wire for the alternator go through the BCM or is it just an ignition feed via the instrument cluster? pulling my hair out now!!

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Sat 27 Jun 2015 22:38
renault master 2005 - Renault master will only charge at 12.5 volts????? - elekie&a/c doctor

The voltage of 12.5, is that measured at the battery or the main terminal at back of alternator.?The w/light circuit seems to go back to the cluster.

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Sun 28 Jun 2015 00:09
renault master 2005 - Renault master will only charge at 12.5 volts????? - focussed

Try powering the exciter wire terminal up direct through a low wattage bulb from a battery postive to find out if that improves the charge voltage, but disconnect the existing wire first.

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Sun 28 Jun 2015 11:11
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

yea i have tried this , but still doesnt alter the charge rate, going to have another look today, going to check all the earths and run a new wire from the clocks then all can be is a faulty new alternator????

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Sun 28 Jun 2015 11:15
renault master 2005 - Renault master will only charge at 12.5 volts????? - elekie&a/c doctor

So,does the warning light work?

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Sun 28 Jun 2015 11:27
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

warning light comes on with ignition and goes out once started??

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Sun 28 Jun 2015 11:14
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

its measured at battery and back of alternator, yea looked on auto data and it looks like it just goes to back of clocks, so must just be a ignition feed??? going to check voltage from back of clocks and if needed run a new wire, then clean all the engine earths then i will be stumped again!!!! thanks for reply !!!

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Sun 28 Jun 2015 11:26
renault master 2005 - Renault master will only charge at 12.5 volts????? - Railroad.
Does the charging lamp come on with the ignition on and go out when the engine is running? If so this is normal and no further checks need to be done.

Check the alternator main cable back to the battery, and do a volt drop test to make sure there is no more than 0.5v loss with the engine running and all loads switched on.

Check the alternator earth in exactly the same way.

Test the battery voltage, and if you have a current clamp check the alternator amps output both on the alternator cable and at the battery to see what it's accepting.

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Sun 28 Jun 2015 11:32
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

Hi thanks for reply, yea battery light comes on and goes out, battery voltage does drop more than .5 when under load! could this be a bad connection or bad battery lead?

alternator earths have been cleaned, and check one of the engine earths but not them all yet!

i havent got a current clamp but il try and borrow one!

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Sun 28 Jun 2015 11:51
renault master 2005 - Renault master will only charge at 12.5 volts????? - Railroad.
In that case the most likely fault is a bad connection or a high resistance in the cable between the battery and alternator. Confirm this by temporarily connecting a jump lead between battery positive and the alternator main terminal. Be sure to use a suitable cable heavy enough to carry the current. A normal jump cable from a jump lead set will do.
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Sun 28 Jun 2015 12:34
renault master 2005 - Renault master will only charge at 12.5 volts????? - elekie&a/c doctor

If the voltage at the rear of the alternator is the same as at the battery,then I can't see this being a wiring high resitance.Also important to check any earth voltage difference between alternator body and engine block.

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Sun 28 Jun 2015 12:52
renault master 2005 - Renault master will only charge at 12.5 volts????? - Railroad.
He said he has a volt drop between the battery and the alternator. The maximum acceptable volt drop is 0.5v. Any more and the system will not charge properly.
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Mon 29 Jun 2015 13:37
renault master 2005 - Renault master will only charge at 12.5 volts????? - Peter.N.

I would be inclined to check the accuracy of your meter on another charging system, you should have about 14.4 volts.

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Mon 29 Jun 2015 19:17
renault master 2005 - Renault master will only charge at 12.5 volts????? - fat.pete17

found what it was today!!!!! and i checked everything electrical and it all checked out, now what i couldnt understand was when i reved it up the voltage dropped, i found that there are 2 ways of routing the aux belt and the van had it on the wrong way , so when the alternator was under load it slipped on the belt, once routed the right way i got 14.5 volts and all was happy days!!!!

wont be taking it to a local garage again as they fitted the belt a few weeks ago and wreaked the new belt but was good enough for a while!!

thanks for everyones comments most helpful,

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Mon 29 Jun 2015 22:33
renault master 2005 - Renault master will only charge at 12.5 volts????? - Railroad.
Well done. Glad you got it sorted and thanks for letting us know. I wish more people would.
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Mon 29 Jun 2015 22:57
renault master 2005 - Renault master will only charge at 12.5 volts????? - elekie&a/c doctor

Good to see a conclusion on this .Bit of a shame that a vital piece of info was omitted in the original post.The fact that the voltage reduced with load would probably have got to a fix sooner.

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Tue 30 Jun 2015 00:46
renault master 2005 - Renault master will only charge at 12.5 volts????? - Peter.N.

Yep, pleased to see you got it sorted, some faults seem to defy logic.

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