Battery Opinions Please

goldeneye243

goldeneye243

Senior Member
T6 Guru
I just invested in a BM2 thanks to @Dellmassive and fitted it in the week.

Tried to start the van this morning and it was dead (nothing to do with the monitor!).

Rather than call VW assist, I used my GB70 to start it (tnaks again @Dellmassive ) and ran it for two sets of 40 minutes. Voltage is still low.

charging.jpg

And yes, it is a Moll battery, but the van does get used for quite a lot of short journeys.

Thanks :)
 
Glad we could help out....

And as above, get the MOLL battery swapped out. =)

Also 2x 40min engine runs wont help a flat battery....it will need a proper smart charger on EHU for up to 24hrs.
 
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@goldeneye243 how did you get the volatage/time plot above?

it doesn't look like the normal BM2 screen shot we normally see. (though the data looks the same . . . . i take it the bottom scale is in minutes? 1-600 mins?)
 
I used the export function and had a look at it in excel.

The scale is actually two minute intervals - The excel file isn't the most useful as it is not stored in a decent format. I will spend a bit of time at some point to make a template for it...
 
goldeneye243 said:
I used the export function and had a look at it in excel.

The scale is actually two minute intervals - The excel file isn't the most useful as it is not stored in a decent format. I will spend a bit of time at some point to make a template for it...
Click to expand...
oh very nice . . . . showing your Excel skills there =]

the plot above seems to show a resting voltage of about 12.2v . . . . . was this the same time period that the van wouldnt start and you jumped it? . . . . and the 2 40min charge runs?
 
Dellmassive said:
oh very nice . . . . showing your Excel skills there =]

the plot above seems to show a resting voltage of about 12.2v . . . . . was this the same time period that the van wouldnt start and you jumped it? . . . . and the 2 40min charge runs?
Click to expand...

Yes, the resting voltage was just over 12 volts. The regions at just under 15V are the charging runs.

I'm going to charge overnight and see what happens in the morning. I have only really had problems starter the van since I put the monitor on. Has anyone had any issues with the BM2 itself? I'm inclined to think it was coincidence but worth asking the question...

Not sure whether to leave the monitor on or not...
 
No issues with any of the 7 I have.....

The current draw of a BM2 is negligible.
 
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How do I tell if the battery needs replacing?

I don't want to call out VW assist and have them tell me the battery is fine...

From today - Charged overnight, then a 4o minute drive to work. Sitting during the day, with the doors opened a couple of times to have a look at the van...

191202%20starter.jpg

I guess it will be interesting to see what the voltage is in the morning...
 
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Bit more battery data plotted -

191205%20Battery.jpg

Does anyone happen to know if this is the profile of a defective battery? Would be good to know when it next goes flat and I call VW assist!

Any starter battery plots would be useful to see...

Thanks
 
If it’s a Moll battery, you don’t need to worry about all the detective work. They are known to be defective so just get it replaced on warranty.
 
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