Why enough battery capacity can still fail to start a fridge
A battery can contain plenty of energy and still have an inverter that cannot start your appliance.
Three specifications, three jobs
Wh describes stored energy. Continuous W describes sustained output. Surge W describes a brief output capability under specified conditions. Compare all three using the exact model documentation. Peak ratings without a duration or applicable test condition are difficult to use in a real plan.
An illustrative overlap check
Suppose a motor needs 1,200 W to start and uses 150 W while running. Other connected loads total 100 W. A simple screen is 1,200 + 100 = 1,300 W during startup, followed by 250 W of running power. The planner uses this one-start-at-a-time approach. It cannot confirm the voltage waveform, startup duration, or simultaneous-start behavior of your equipment.
Average watts are a different measurement
A refrigerator averaging 50 W across a day can draw much more when its compressor is on. An energy average is useful for runtime. It is not a replacement for running and startup specifications. When editing a fridge in the planner, use its running watts and active hours for energy, then check a suitable surge estimate separately.
Resolve uncertainty before relying on the setup
Ask the appliance or battery manufacturer about the exact combination. A supervised compatibility test is more informative than a larger nominal capacity alone. Do not repeatedly force starts, bypass protection, or exceed any outlet, cable, or equipment rating.
Sources & further reading
Numerical examples and default device values are illustrative unless explicitly described as a measurement. Consult the manuals for your own equipment.
Make it a plan for your home.
Choose your devices and edit the assumptions.
Open the backup planner