220V INVERTER :
PURE SINE OR NOTHING.
Plugging a $2000 MacBook into a cheap inverter is an absolute guarantee to destroy it. Here are the only real rules.
1. Pure Sine Wave
The electrical grid in a house provides alternating current forming a perfect curve. The majority of cheap Amazon inverters (often called Modified Sine) spit out a 'staircase' wave.
If you plug a computer, an electric toothbrush, a blender, or an e-bike charger into it: it will hiss, heat up, and fry your motherboard. You absolutely need the certified label: Pure Sine Wave.
2. The Idle Power Draw Trap
"I'll get a 3000W inverter to be safe!" This is a massive rookie mistake.
An inverter connected to batteries, even with no appliance plugged in, consumes energy just to run and stay powered on (usually 1% to 3% of its max power). A 3000W inverter left on 24/7 can drain 60W continuously, or 1400Wh per day. It will literally drain your battery flat in 24 hours just by "existing".
3. Power Calculation (+25%)
Does your biggest appliance draw 800W (e.g. boiler)? Never get an 800W inverter. Inverters suffer when pushed to their max. Apply the strict safety margin of +25%. For an 800W appliance, you need a nominal inverter of at least 1000W.