The inverters with the lowest surge ratings are the high-speed electronic switching type (the most common). These are typically from 25% to 50% maximum overload. This includes most inverters made by Statpower, Exeltech, Power to Go, and nearly all the inexpensive inverters in the 50 to 5000-watt range. The highest surge ratings are the transformer based, low-frequency switchers. This includes most Xantrex, Magnum, and Outback Power. Surge ratings on these can range up to 300% for short periods. For more details visit inverterreview.com