Any changes in performance are easily noticed with this monitor.
Brand :National Luna
Simple and easy to read display gives a constant indication of the charging performance of both batteries whilst you are driving. If 4 green LED's are showing then the batteries are receiving an excellent charge. Only 1 or 2 green LED's indicates a charging problem.
When stopped, the number of orange LED's showing indicates the remaining storage capacity of each battery.
Any changes in performance are easily noticed and give advanced warning of a decling battery or other problem.