Battery Planning Facts

A battery's rated watt-hours are not what reaches your device: through an AC inverter this site plans with 85% efficiency, so a 1,000 Wh rating delivers roughly 850 Wh of AC energy.

Explained in: Inverter Efficiency Losses

Draining a battery to zero on paper is not a plan: the calculators keep a 10% reserve by default, so usable energy is always below rated capacity.

Explained in: Reserve and Battery Health

A refrigerator's average draw is far below its label wattage because the compressor cycles on and off; runtime estimates here model that duty cycle explicitly instead of using the label number.

Explained in: Duty Cycle Explained

Startup surge and running watts are two separate limits: a station must clear a device's surge peak for a moment and its running watts continuously, and failing either one means the load will not run.

Explained in: Surge Power vs Continuous Power

Watt-hours, amp-hours, and voltage are one equation: Wh = Ah × V, which is why a 12.8 V 100 Ah battery stores 1,280 Wh regardless of how it is marketed.

Explained in: Watt-Hours, Amp-Hours, and Voltage Explained

LFP (LiFePO4) and NMC lithium chemistries age differently; this site records battery chemistry per model where the maker publishes it — and leaves it unknown otherwise — while avoiding universal cycle-life claims, because none survive contact with real usage patterns.

Explained in: Battery Chemistry, Depth of Discharge, and Aging

Cold reduces usable battery capacity, but by how much depends on the pack and the temperature; the calculators treat cold-weather loss as an adjustable planning percentage, not a verified measurement.

Explained in: Cold Weather Battery Runtime Guide

Solar panel ratings are lab numbers: for real-world charging this site derates solar input to 75% of the panel rating by default before estimating charge time.

Explained in: Runtime Methodology and Trust Policy