I travel with two of these for powering the Car Freezer and Refrigerator with both of them hooked up to one. I have determined that both can run for approximately 28 hours which allows me to switch the batteries out each evening and taking the there other one into the hotel to recharge! The battery is much lighter than the freezer/fridge and this allows them to be on even when the van is off (which would be an issue if I was using the van's power). I purchased these on Amazon.