Reference
Reference: The Arithmetic and the Limits
The stages tell you what to buy and in what order. These pages explain the arithmetic underneath them and the places where the arithmetic stops applying. The first one is the one to read even if you read nothing else on this site.
What a Power Station Is Not
A portable power station is a box of stored watt-hours with outlets on the front. That is a useful thing to own, and the first three items on this page are the ones people get wrong in ways that hurt someone. Read those three even if you skip the rest.
Read this referenceWatt-Hours and Amp-Hours
Two units show up on backup power listings and they are not interchangeable. Watt-hours describe energy. Amp-hours describe charge, and only become energy once you know the voltage. Getting this straight is the difference between comparing two products and comparing two marketing numbers.
Read this referenceSurge Watts and Continuous Watts
Every inverter has two wattage numbers, and the smaller one is the one that matters for most of the day. The larger one is the one that decides whether a motor ever gets going at all. Confusing them is the most common reason a battery that looks big enough shuts off with an error.
Read this referenceLithium Batteries and Care
A lithium pack that is treated normally is undramatic and lasts years. The failure modes are rare and severe, which is a bad combination for guesswork, so this page is mostly about what not to do and where the real numbers come from.
Read this referenceSurge Protectors Are Not Backup Power
A surge protector turns one outlet into several and is supposed to absorb a voltage spike on the way through. Neither of those jobs has anything to do with keeping equipment running when the utility drops. It is worth owning one; it is worth knowing what it does not do.
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