About
About This Site
BackupWattCache is a reading site about buying backup power in a sensible order. It exists because the category is sold on capacity numbers, and capacity is rarely the thing that decides whether a household copes with an outage.
What is here
The site is organized around order rather than product. There are 5 stages, from the one that costs nothing to the one most households should not reach; 10 device pages showing what a household load actually draws and how the arithmetic works; 5 reference pages on the arithmetic and its limits; two calculators; and 5 gear categories holding 40 products in total.
Every stage states what it does not cover and what not to buy yet. Those two blocks are the reason the site exists, and they are why it will sometimes tell you to close the tab and go label your breaker panel instead.
What this site does not do
Limits this site holds to on every page
- It does not test products. Nothing here has been measured, opened, run down, or compared on a bench. Every specification is what the listing states, and where a listing states nothing, the page says so.
- It does not give electrical advice. It does not describe connecting anything to a wall outlet, a breaker panel, or house wiring, and it does not describe a shortcut around a licensed electrician and a transfer switch.
- It does not address medical or life-sustaining equipment. There is none in any list, any calculator, or any estimate on this site, and there never will be.
- It does not publish its own engine-starting procedure. Clamp order and polarity are published by the maker of your jump pack and by your vehicle manual, and they differ between models.
- It does not describe opening, repairing, rebuilding, or reviving a battery pack, at any capacity, for any reason.
- It does not sell solar panels or fuel-burning generators, does not estimate solar recharge, and does not advise on engines.
- It does not publish prices or ratings, and it does not guarantee that any unit will run any appliance for any length of time.
How the numbers are produced
One formula runs the whole site: usable watt-hours are the rated figure multiplied by a single derate of 0.85, and hours are those usable watt-hours divided by a steady wattage. That derate covers inverter conversion loss and the portion of a pack that will not come back out. It is a planning figure applied uniformly, not a measurement of any model.
Where a load cycles on and off, a duty share is applied before the division and is stated on the page. Every hour figure the site shows is computed from that arithmetic at the moment the page is built, rather than typed into prose where it could drift out of step with the data behind it.