Battery completely drained after 3 days of standby

Hi,

The next problem:

A 2-month-old Excide battery has only 3.7V after standing for 3 days in the vehicle.
Caddy, year 2010, 2.0 liter engine, model CFHC, 198,000 km.

The battery has been connected to the charger for about 6 hours and currently reads 12.1V.

The vehicle will be needed tomorrow. Hopefully, a functional battery will be installed, and then it will be driven 150 km on the highway without stopping.
Unfortunately, there is no time to investigate the reasons behind this collapse.

Two questions have been on my mind.
1. Is it possible for this vehicle that forgotten interior lights, etc., could lead to a complete battery discharge?
Is the consumer not disconnected beforehand by software and/or a relay?

"Is it possible for something to fail in such a way that it draws this much current?" Control units, etc.?

Best regards, Roland.

Be prepared for the battery to have died due to being completely discharged.

Hi,
It's certainly possible that the "new" battery is defective. But there are a few things you should keep in mind.
- The battery is likely an EFB (Enhanced Flooded Battery) or even an AGM (Absorbent Glass Mat) battery. If a battery like that is deeply discharged (and often has an indicator), it should not be recharged. It can burst.
- When installing a new battery, the coding must be adjusted (type and serial number). Using the wrong type (e.g., AGM instead of EFB) can lead to an excessively high charging voltage. An unchanged serial number will cause the control unit to believe that the old battery, with its low remaining capacity, is still present. Then it won't charge fully.
- Regarding the background information, I would check the power consumption in standby mode (using an external clamp meter).
hg
Herbert.

As my fellow forum users have already mentioned, the battery is most likely defective. For this model year, the interior light should automatically turn off after a certain period of time X.
Most likely, you'll have no choice but to use a clamp meter to check the quiescent current and, in the process, remove each fuse one by one.

The battery is an Exide EA770, which is a flooded lead-acid battery, not an AGM or EFB type. I think there's nothing to adjust.
I stopped the charging process after approximately 20 hours, when the charger displayed a voltage of 14.5V, for time-related reasons.
The battery is working perfectly; after 24 hours of inactivity, it shows a voltage of 12.9V. Rest current measurement will be performed next.

Does the Caddy not have an automatic start-stop system?

No, he didn't.

After another 24 hours, there was no voltage drop whatsoever, and it actually increased by 2/100 due to a warmer battery.
I think I can probably skip measuring the quiescent current.

It seems that almost only the battery itself was failing, but now everything seems to be okay again.

I'm at a loss...

Nevertheless, I would still take the trouble to measure the quiescent current. Then, the suspicion that the problem might be related to the battery is likely to be confirmed.

If the battery can be recharged from a remaining voltage of only 3.7V, the voltage holds steady, and it doesn't collapse again when starting the engine, then it probably isn't defective.
It was completely empty until the attack.
hg
Herbert.

5mA, approximately 3 minutes after the doors are closed.

That should probably be okay.

There are two possibilities remaining:
1. temporary malfunction of a control unit.
2. Battery got hit.

2 is, as a flawless function is virtually impossible to achieve.
1 is not understandable, but conceivable.

I definitely have the tools, jump cables, and a fully charged spare battery on board now.

The battery is still under warranty. Can you take them to the dealer so they can be inspected?

I can do that; I purchased it locally from a specialty store.
Do I want to do it? Not necessarily.

I will wait and see, but I have made preparations for any emergencies.