I would like to build hour counter which can remember value when I pull out batteries from the vehicle and it count hours when vehicle has power back.
This counter must be hidden in the vehicle - without display. Hours could be readed with other wireless modul.
Is there on the internet simular project or parts of this project where could I get help?
Is it possible to read more of those counters (different addresses)?
You can buy hour counter gauges - typically used on industrial plant or boats so engine run hours are measured. Fit under the bonnet.
If you want a techy solution have a look a 8266 plus a DS3231 battery backed clock.
Mr google says ...