Charging problem with VMax

Hello guys, I want to shield you: With my Max the battery is emptied during the ride. In order to keep them alive I have to keep the Max of traffic lights always in the gas, otherwise it dies. I measured the following values: Battery fully charged: 12.8V Charge voltage increases to a maximum of 13.2V, voltage does not break together with higher dreg numbers Residency of windings: 0.7Ohm; 0.7Ohm; 0.7Ohm AC voltage of Lima measured between phases: approx. 21V i.e. 63V g It’s not possible to detect a mass closure, all plugs cleaned and treated with contact spray According to the workshop book, the resistance must be about 0,35 ohms. You think there is the problem to look for. Furthermore, I had read that when using double headlights, as in my case, the Lima already comes to the limits. what do you think?