A 1,500 Wh battery in a Systainer, delivering 230 V mains at 3,680 W continuously — roughly the energy of twenty tool packs, in a 16 kg case that stacks with the rest of your kit. It runs corded machines where there is no supply, and unlike a generator it is silent and produces no exhaust, so it can be used indoors and in an occupied building. Splash-proof to IP44, and it charges in about three hours.
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