Audi A4 B5 (1996) 1.6 Petrol - Intermittent Starter Issues & Electrical Reset in Cold & Frost

Hello

I have a problem with my car, specifically with electrics. Audi A4 B5 1.6 Petrol 96 year Namely, as outside it is Cold and Frost outside at about 0 to -5 and below it the Starter does not turn. As if the Battery was not supplying Current to the Starter. It does not happen constantly only once in a while ok for two months. When I turn the key, it resets my Radio and turns it off completely to the Factory settings, and the car counter also resets. You can hear 3 short Sounds. If he doesn't want to start and connect the battery to the charger for 10 minutes, he will start without anything. Similarly, it happens when the Car turns on the Vent and comes from 10-20 minutes with the engine turned off and the ignition key turned on and the lights in the Car either passing or lights in the Headliner. I really don't know what to do anymore and where the problem lies. I checked the battery charging:
At a standstill:
-12,28V
With the engine running:
-14.00V and jumps up to 6.00V
With the engine running with the Windscreen heating on, High beam (Long), Air flow on max:
- 13, 38V and also jumps up to 4.00V
I didn't check the alternator because I don't know how to connect it with a Multimeter

Do you know what could be wrong with him?

Maybe the battery has a torn off plate and once it is ok and other times not, maybe the ground or power cables at the battery can clamp.

Hello .
Measure the battery after these few minutes of running the airflow, with the engine off. You can also switch on the dipped headlights instead of the blower. If after these few minutes the lights fade or go out, it can mean that the battery is ending its life. If you drive short, short distances, it can be that the battery is quite discharged.10 minutes under the rectifier, it is very little to fully charge it. If the battery is not age, then connect it for at least 10 hours. Of course, it does not hurt to check the clamps, mass (battery-engine), as well as power consumption at standstill.

But the measurements show that the battery is good. The measurement jumps are puzzling

To check the battery weight-> body-> engine.

robokop wrote:

To check the battery weight-> body-> engine.

The cable from the mass going from the car body to the battery is a bit corroded. I had water drains clogged and once there was water and corrosion entered the conduit. Could this be the reason? And can I connect the ground wire to another place?

What problem do you have to clean the ground cable (battery - body, battery motor). If the starter does not turn, then connect the battery minus the motor, for example, quickly by firing leads. Measure the voltage during firing on the battery, and the second measurement in this way;
1 meter tip to (+) battery
2 meter tip to engine body

I took the Battery measurement. OK
But the measurement shows that there is no charging. The measurement stopped at 13.76 V under load (lights, air flow, etc.) and jumped to 0.90 V

Make a measurement on the alternator, what is the difference from the measurement on the battery. There should be a fuse on the battery from the alternator. Check this place, it may be burnt.

nikusert wrote:

Make a measurement on the alternator, what is the difference from the measurement on the battery. There should be a fuse on the battery from the alternator. Check this place, it may be burnt.

Where's the fuse?

Is the battery box black with fuses.