EMERGENCY VEHICLES ELECTRICAL SYSTEM

Recently we have been asked to investigate electrical problems in a large fleet of emergency vehicles. These vehicles (some 12 different models) were basic cars - some brand new, some with some mileage already - fitted with additional computers, transceivers, search lights, warning lights, electrically powered medical equipment, etc.
# in about half of the fleet the alternators were found to be inadequate (ref. ALTERNATOR IN CARS in our blog);
# in all of the vehicles the batteries were faulty (ref. BATTERY IN CARS, or MULTIPLE BATTERIES IN CARS in our blog);
# in vehicles with dual batteries the two batteries were connected in a way that promoted premature failure of one of the batteries, leading to the subsequent failure of the remaining battery.
Some of these vehicles required a replacement battery (or batteries) every two weeks. Needless to say, the replacement batteries were also faulty (again, ref. BATTERY IN CARS in our blog).
The additional component's wiring & its termination was not done to the standards applicable to the wiring in the original vehicles, the workmanship was poor, which all contributed to a continuous litany of electrical problems.