hand-made Start-Stop / generelles Startverhalten | Posts 16+

Here's how the day started this morning:

With swapped batteries?

No, not yet.

I'm also curious as to why it's more intense this time, meaning why the voltage is higher after all the heating elements have turned off.

Perhaps charging the battery (overnight, from Sunday to Monday) actually made a difference.

m;

Hello everyone!

dieselmartin wrote:

... (once jumped

and once failed to start with jump start assistance) .

@Martin:
...like "faulty jump-starting"?? Is something wrong, or what?!

@Ulf:
A lead-acid battery discharged with (very) high currents, down to a voltage of 10.5 volts (discharge end voltage), can still provide approximately 60% of its rated capacity after about an hour of rest... therefore, it doesn't necessarily mean that a TDI engine won't start because of it.

And I'm still of the opinion that the Passat's battery is dead.
Martin's logs indicate a healthy golf cart battery with an open-circuit voltage of more than 12.5 volts, AND a voltage that remains clearly above 13 volts after being turned off (for a short period).
Quite different with the Passat battery: The open-circuit voltage (Martin clearly stated at the top that he had measured it without any load!) was just below 12 volts, then the starter was engaged (charging), and after being turned off, the voltage was well below 13 volts.

Martin, could you swap the batteries between the two cars and then log the data for both of them again? I'd be really interested to see the results.

Best regards from Munich!

Hi, even with 12.3 volts, the Passat battery is either...
burdened or
not full, or when charged.
almost dead.

The battery replacement will have to wait until the end of the week.

The Golf will likely have learned all sorts of new things by then, just as it previously needed to know the steering angle and end stops of the power steering system after the replacement of the steering column control unit. It took longer than replacing the STG.

Or, I could torture my 12V lead-acid bicycle light battery by connecting it to the car.

"Should 1.2 Ah be enough for standby mode, right?"

m;

Maybe? Turn everything off: interior light, radio, ...

Update:

Due to the upgrade from RCD500 to RCD510, I'm currently observing the bus activity and quiescent current.

Shortly after completion, it measures 12.3 volts.
I finished it an hour ago.
Now, he has 12.40 volts at the battery.

I have the hope that...
- that the 510 thread allows my battery to remain undisturbed.
- the battery isn't as dead as the initial log suggested.

m;

DieselBär30x wrote:

@Ulf: A lead-acid battery discharged with (very) high currents, down to 10.5 volts (discharge end voltage), can still provide approximately 60% of its rated capacity after about an hour of standing!! ...therefore, it does not necessarily mean that a TDI cannot be started

. It might be the case, but for the purpose of the log, I assumed no such prior abuse .

The T4 AAB battery is organized (large and heavy, so probably around 70 Ah).

This will buffer the Golf while I drain the battery of my Passat.
Hopefully, the clamp doesn't slip, it always works so awkwardly .


I've always wanted to build a power cable with nice M5 threaded holes, so you can "connect" things securely.

m;

Connect the cigarette lighter cable and the small 12V auxiliary battery to a circuit protected by a 5A fuse.
Then, put the reduced plus into a disposable glove .

Quote:

Lighter

... is switched off by the vehicle's electrical system when "ignition is off".

m;

modern stuff.

Hello everyone!

dieselmartin wrote:

Quote: Lighter for cigarettes ... is switched off by the vehicle's electrical system when "ignition is off".

The idea from KlausiMausi is great! ...because I myself charge my vehicle batteries overnight using this fast and road-safe method .

It's also new to me that the cigarette lighter in VAG cars now runs through terminal 15. *shrug*
My T5 definitely (still) has it connected to terminal 30.

However, I think a 2 Ah lead-acid battery should easily provide enough power for the time it takes to install and remove the car battery.
(Assuming a quiet bus and closed doors!)

Best regards from Munich!

Quote:

(Assuming bus is stationary and doors are closed!)

At least!

Bus quiet, doors closed, but VCDS on the CAN-GW consumes 0.6A on the Passat!

m;

...and what do you need VCDS for when changing the battery? *innocent question*

No, even a small motor drawing around 0.5A shouldn't be a problem for a 2Ah battery, even if it's running for 5-10 minutes.

Best regards from Munich!