The most common reason standby generators fail to start when they’re needed is faulty batteries. To protect against this, it’s important to load test your batteries (and the other components of your generator) on a regular basis. Because batteries deteriorate over time, testing them under load for accurate performance results is essential.
Before conducting a battery load test, a visual inspection should also be completed. Loose cable connections, disconnection from the battery charger and corrosion or debris will affect battery performance and are easy to resolve.
Other concerns that affect battery performance and lifetime include sulfation buildup (due to discharged battery acid or low battery acid levels) and lead debris, which will not be evident during a quick visual inspection. However, the results of these issues will be underperformance of your batteries and generator, which will be obvious during a load test.
What is a load bank?
Load banks are electrical devices that are wired into generators temporarily to mimic a situation where the generator would need to operate at full capacity. A load bank gradually increases the required output of the generator until the generator is operating at its full capacity.
DC vs AC Load Testing
A DC load test is conducted to measure battery performance specifically, while an AC load test is used to force the generator as a whole to operate at a specific kilowatt output.
Load Testing a Generator Battery
Load testing the battery bank within your generator requires the use of a battery load tester. Weak batteries will be more easily identifiable during a load test than a simple multimeter reading because the load test requires the batteries to operate for a sustained period after they use their charge to start the generator.