7. Inverters and APUs

The addition of an inverter to a truck electrical system will reduce hours of use on a diesel-fired auxiliary power unit (assuming that the APU does not already have shore power compatibility). “And, it will reduce maintenance costs and increase APU life,” said Carlson. “An inverter can be used for hotel loads in the cab as long as environmental conditions do not require air conditioning. When those conditions happen, just power up the APU for air conditioning.”

With this set-up, the only time the APU would need to come on is if the batteries drop to a low level. Once the batteries are charged, the APU can shut off again. “This significant reduction in APU run time means a quick payback on the cost of the inverter,” says Carlson.