I purchased this product to use primarily in case my battery died, and secondarily as a portable power source when camping or away from a source of electricity.
The powerpack works great when starting any size car with a completely dead battery. The built-in inverter is great to charge cell phones or run small appliances when camping for example.
The display is very useful, showing either the percentage charge or the real-time wattage being used.
Be forewarned, though, that this item is heavy and portable only inasmuch as it has a handle. I wouldn't lug it too far. Also, while charging is quick through the cigarette lighter cable, it takes a long time through the AC adaptor.
Overall, a great purchase.
Xantrex Powerpack 600 Watt Jumpstarter, Power Inverter and Backup Power Source
