Battery voltage indicator
In order to assess the state of charge of the consumer battery, I recommend the use of a battery monitor. Only with this monitor the current state of the battery is displayed exactly.
If you do not want to install a battery monitor, you can For a rough assessment of the charge state, use a simple, inexpensive LCD voltmeter. Please note that the battery must have been in a resting state for approx. 2 hours to assess the state of charge. Idle state means that the battery has neither been charged nor has current been drawn from it.
With the voltage display you can also check if the battery charger or the alternator is working correctly. Depending on the type of battery, the voltage of the first charging phase is between 14.3 and 14.7 volts and is then reduced to 13.6 to 13.8 volts
When charging via the alternator, the voltage is about 13.8 volts
To avoid voltage drops and incorrect measurements, the voltmeter must be connected with a two-wire cable directly to the battery (do not forget the fuse directly on the battery !)
You can buy the voltmeter from Conrad under the order number 134473-62.
On my Duetta I was able to install this display in the switchboard instead of the not very meaningful LED display. Only the section must be enlarged a little bit.