Spannungsversorgung ausreichend? | Posts 16+

Hello everyone,

Attached is a log of my 7.5-year-old AGM battery with a 140A alternator, showing the readings during starting and then at idle.

I have added the following consumers to the system:

- Heated rear window
- Maximum ventilation.
- Windshield wipers, maximum.
Fog lights.

The total consumption is approximately 85 plus or minus 5 amps. Importantly, the battery is never discharged.
According to my understanding, the "generator reserve power" display indicates the amount of power that could still be supplied if the excitation current were adjusted to its maximum value at the currently prevailing speed.

@ Steffen G:
"Unfortunately, your readings only provide a snapshot in time. You're showing a negative battery current, which indicates discharge (see the starting process at the beginning of my log). Was the engine running constantly at idle, or were you playing with the accelerator?"

Your laser machine is definitely not being used to its full potential; there must be another underlying problem.

brezelmann01 wrote:

@ Steffen G: Your values unfortunately only show a snapshot in time.

Hi!
No, those are not my values.
This is from VAG-Driver.

He only quoted me because I had phrased something incorrectly in a previous post.
I'm sorry about that, Andreas; it wasn't meant like that!

Oh shoot . Please excuse me. You are absolutely right.

Always remember: I = U/R. Where U represents the regulator voltage and R represents the load. The alternator with a regulator will not supply more current than it is designed to. The regulation is based on the output voltage, regardless of how much current the alternator could potentially provide.
hg
Herbert.

Hello Herbert,

What are you trying to get at? The original question was whether the Lima would be able to provide the necessary current in the LL (low-voltage line). Theoretically, it should be able to do that. And the reserve power reading also indicates that. Nevertheless, there's still this snapshot showing the battery being discharged.

Greetings, pretzel man.

"I made two changes related to the battery management system. I installed and programmed stronger AGM Banner batteries. In doing so, I noticed that one of the values was set for a conventional lead-acid battery. I adjusted this value to reflect an AGM battery. Of course, the vehicle originally came with an AGM battery from the factory."

Good morning!
The vehicles back then (or even still today?!) were all coded for wet batteries. Mine was too. I once recorded voltage curves for both AGM and wet battery configurations, but couldn't detect any differences. Even with the "wet" setting, the charging voltage was appropriate for an AGM battery. I left it on "wet" back then, and there must be a reason for that.

Best regards,

Perhaps I should put that back .

Okay, I did that. I switched the coding back to "wet cell" and recorded the following data.

Idling with headlights (Xenon) on, radio playing, and ventilation set to automatic:

Address 61: Battery Management (7N0 907 534)

14:09:15
13.50 V - Generator nominal voltage.
2.125 A - Excitation current.
13.312 V Battery voltage.
1.9 A Battery current.
90.0% Battery Charge Level
98.0% Battery aging based on charge cycles.
77.0% Battery aging related to performance.
5.4 mΩ Internal resistance of the battery.
69 Ah Removable battery pack.
12.70 V Battery resting voltage.

2. Measurement taken with the engine idling, headlights (Xenon) on, radio playing, ventilation on automatic, both seat heaters set to the highest level, steering wheel heating and air conditioning activated.

14:11:39
15.00 V - Generator nominal voltage.
2.750 A Excitation current
14.720 V Battery voltage.
5.1 A Battery current.
91.0% Battery Charge Level
98.0% Battery aging based on charge cycles.
77.0% Battery aging related to performance.
5.4 mΩ Internal resistance of the battery.
69 Ah Removable battery pack.
12.70 V Battery resting voltage.

I forgot to record the generator's power output .

Hello,
Okay, for now. I recommend creating a data log so you can see the chronological sequence of events. Right now, these are just snapshots and essentially useless.

Best regards,

Hello,

It's strange that the change in battery voltage hasn't resulted in any noticeable difference. Shouldn't the charging voltage be higher for AGM batteries?

Please consider the following when reviewing the information on page 1: This 7N model likely has regenerative braking (indicated by the "BM" designation on the vehicle data plate), and the battery is not charged to 100% due to the charging strategy. Instead, it's typically maintained at 70-80% to reserve capacity for regenerative braking.

Roger wrote:

When considering the information on page 1, please note that this 7N likely has regenerative braking (indicated by the additional designation "BM" on the vehicle data plate) and that the battery is not maintained at 100% during charging. Instead, it is kept at 70-80% to reserve capacity for regeneration.

Okay. The 7N is a BlueMotion model with regenerative braking. I would even go so far as to say that the "wet battery" or AGM coding has no effect.

Did you perhaps disconnect the battery sensor to disable the start/stop function?

Roger wrote:

Did you perhaps disconnect the battery sensor to disable the start/stop function

?

No. Why are you asking?

That would also take care of the regenerative braking system as a side benefit.
Many people do it that way.

We're back from vacation and have driven approximately 2500 km. After 3 days of being parked, and with the sliding doors and tailgate being opened and closed, the battery is in excellent condition. This was measured using the same measuring device.

I still believe that with this equipment and a daily commute of approximately 40 km, it may not be sufficient to keep the battery well-charged during the winter months. Therefore, recharging during the winter months is highly recommended. Of course, things are different in the summer.