Usefull gizmo from Gammatronics for a tenner to monitor battery voltage when garaged and to check dynamo charging.https://www.ebay.co.uk/itm/6v-12v-24v-P ... 2749.l2649
Doubtful at first but checked the accuracy of the programme #3 (6V) on my variable voltage psu this gave the following:
7.6v and above red/green flashing (Overcharging)
6.7v to 7.6v green steady (Charging)
6.3v to 6.7v green blinking (Bike parked)
6.1v to 6.3v yellow blinking (Battery Low)
6.0v to 6.1v red blinking (Battery even lower!)
below 6.0v blank. (Battery dead!).