VXR8 Battery Charging

[Englishman]

A newbie question I'm afraid.

Just got my VXR8 last week and had flat battery yesterday after lots of cleaning and other tinkering with little driving. So could have just been down to me. But as the dealer is 50 miles away I want to be as sure as I can there is an issue before I go.

The battery is now charged, but I've noticed that the voltmeter indicates just under 15v after starting and then drops back slowly to just under 13v after a run. Being new to me I don't know if this is normal behavior or if it indicates a charging problem. The battery charging voltage is pretty steady with all other cars I can think of, but maybe the VXR8 charging circuit is more sophisticated?

If another VXR8 owner could take a look that'd give me a pointer one way or another it'd be really appreciated!

TIA

[ringram]

Known problem actually. I had my battery replaced under warranty. I had to tell them the fix gleaned from Oz forums.
Basically you need to ask for all your BCM firmware to be updated. It will then charge a lot better and all will be well

[Englishman]

Thanks.

Do you happen to have a link to the explanation that I can forward? Also, did your battery actually need replacing and is BCM Battery Control Module? Questions and more questions!

[ringram]

No technote, but if you just ask them to upgrade the BCM (Body Control Module) then you should be ok. Battery might be ok if you are lucky.
There was just a thread on ls1.com.au mentioning that Holden had a fix and it consisted of getting the BCM to charge the battery at a higher voltage. The older BCM would wait until it got to 60% or 80% or something. I noticed the problem when it was only cranking over slowly when it was hot. But its definately not a problem any more.

[stevemj]

ringram said:

No technote, but if you just ask them to upgrade the BCM (Body Control Module) then you should be ok. Battery might be ok if you are lucky.
There was just a thread on ls1.com.au mentioning that Holden had a fix and it consisted of getting the BCM to charge the battery at a higher voltage. The older BCM would wait until it got to 60% or 80% or something. I noticed the problem when it was only cranking over slowly when it was hot. But its definately not a problem any more.

Ringram

Could you send me a more specific link please? My VXR8 is into Motor Bodies on Tuesday for Sat Nav s/w upgrade and I'd like them to do this as well. However their VXR8 expert claims to be unaware of this, so I would like evidence to encourage them.

Many thanks, Steve

[ringram]

Sorry mate, like I say no technote. Just ask them to update all your firmware for the BCM etc. He doesnt need to know anything else.

[stevemj]

I had my ECM updated by Motor Bodies and queried the charging voltage.

After some 'discussion' their VXRB specialist (Daniel, I think) he gave me a copy of Vauxhall's technical article on the subject.

Ringram - would you like a copy? I'd pm you if I knew how.

Steve

[ringram]

Does it charge better now? Mine does.
Im ok you can just quote the technote ID for the issue on the forum if you like. That will help others.

I think it was to do with the trigger level for charging the battery that the BCM used. I think they changed it from 80% to 95% or something simliar. Does that sound right?

[stevemj]

Ringram - you have mail.

[stevemj]

This is the info from Vauxhall (if moderators are not happy with the copyright concerns, then please remove)

[URL=http://imagefra.me/view.php?img=/2/7/][/URL]

[URL=http://imagefra.me/view.php?img=/2/7/][/URL]

Click on the URL rather than the thumbnail.

The charging algorithm is indeed complex and would lead to some uncomon voltages being displayed.

I hope this is useful.

Steve

Edited by stevemj on Friday 31st July 10:01