Battery Charging - Main Battery Chassis Point -

[CamperCaz]

Battery Charging - Main Battery Earth Point -

so weve all be told NOT to bridge out the battery monitor on the neg side of the battery when charging it.

This is so the ECM can correctly gauge the SOC (state of charge) of the starter battery by monitoring the current flow in and out of the battery . . . . even when the van is sleeping.

View attachment 34123

OK fine, no problem there . . . . . so my question to all is where are you picking up your chassis ground point? . . . . and one thats good enough to allow the 15amps charge that my charger is putting out?

View attachment 34125

currently all i found was this small stud under the valence . . . . . but it seems a bit iffy . . . .

View attachment 34124



no i also this question as the manual clearly states that you must use a chassis or engine block ground . . . . . but where is one? nearly everything is plastic and my lead is to short to reach down to the block.


View attachment 34126


now as a comparison, our old BMW has the battery in the boot, it has a nice long chunky cable that runs along the under-body and up into the engine bay, to a nice convenient jump-point under a nice red plastic cover under the bonnet by the suspension turret . . . . . now right next to this point is a large chunky BOLT type thing bolted to the chassis for the purpose of a ground jump cable connection.

so has VW just not done anything about the NEG connection point?. . . . . or am i missing something?

why do you guys do?

EDIT: additional info,

View attachment 36699

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12 Earth point, on left in engine compartment
q Specified torque: 9 Nm
13 Earth point, on right in engine compartment
q Specified torque: 9 Nm
15 Earth point, on cylinder head
q Specified torque: 9 Nm
607 Earth point, on left in plenum chamber
q Specified torque: 9 Nm
614 Earth point 2, on right in engine compartment
q Specified torque: 20 Nm
624 Earth point, starter battery
q Specified torque: 20 Nm
640 Earth point 2, left in engine compartment
q Specified torque: 9 Nm
642 Earth point for electronically controlled fan
q Specified torque: 9 Nm
714 Earth point on right of engine
q Specified torque: 20 Nm

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******************************************************

• Charging:
• Battery Chargers - How I Did It -
• Battery Charging - Main Battery Earth Point -
• Battery Monitoring -- How I Done It --
• [Guide] Battery Maintainer (for Starter battery) -- How I Done It --
• Which Jump Starter?
• Seat Base Electrics, EHU+Charger+solar+install - How We Done It -

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I couldn't find a dedicated NEG point

 

[whodat]

Don't know if this has been said but would think this would work - will try it when it stops raining, and if I remember, and if I can be bothered.

If you have a voltage tester (a simple one which will do DC) that can test batteries, switch the tester on, turn it on to DC (15v or higher setting), then hold (battery tester cable) positive clip/point to positive on battery and negative clip/point to the bolt you think might be the earth.
If you have found a correct earth, you should get a reading on the tester.
If you haven't, then it won't be the earth or it needs the paint scratching off and try again.

 

[roadtripper]

Don't know if this has been said but would think this would work - will try it when it stops raining, and if I remember, and if I can be bothered.

If you have a voltage tester (a simple one which will do DC) that can test batteries, switch the tester on, turn it on to DC (15v or higher setting), then hold (battery tester cable) positive clip/point to positive on battery and negative clip/point to the bolt you think might be the earth.
If you have found a correct earth, you should get a reading on the tester.
If you haven't, then it won't be the earth or it needs the paint scratching off and try again.

This is an inherently safe way of initial testing as voltage sensing in a multimeter is very high resistance - so an accidental test across ground and 12v is fine.

Downside in confirming a good ground point is even a very high resistance will likely pass this check but not work well under load.

So once you've found a good site the second test is to put the meter into resistance mode and very carefully measure the resistance between a known good earth or the battery terminal and the test site - you want it to read zero or very very close. The reason I'd only do this as a second check is that in this configuration your meter would be a low resistance short if accidentally connected between 12v and ground. Also only ever do this on the ground circuits.or disconnected circuits as your meter will be using its battery to put a small current across the probes to do the test.

As an aside if your meter has a continuity check, usually with a buzzer, that's great for quick circuit checks but not for this test. It's a form of resistance testing but generally a meter will accept small resistances as "continuity" in this mode - that makes it much more tolerant for quick testing meaning you don't have to really ensure the probe tips are on very clean metal, but it would allow slight corrosion or paint and still pass if trying to ensure your ground is very low resistance.

 

[whodat]

Cheers.
I'm used to working on 'old' vehicles so all this is new to me. With new vehicles - I prefer not to do anything under the bonnet except refill windscreen washer fluid.

In the really old days when I was starting out in the world and before I knew anything at all about vehicles, I had to fix windscreen wipers on a 1980's transit. I had to ask someone to confirm that if I got it wrong it wouldn't damage the engine. They laughed.
Nowadays, that really could happen.