Previously I've used jumper cables or, at home, hooked it up to a charger. Problem is, cables need another car handy and the charger isn't fast if you need to be somewhere.
Then I bought one of these right after the last time my battery needed a fast jump. It was a Black Friday or Cyber Monday deal and considerably cheaper that current list (which still isn't outrageous for this sort of thing). My battery hasn't died since then so I haven't been able to properly test it for its main purpose but I have tried its other power supply functions and it did well.
Unfortunate (or fortunate, depending how you look at it) that I haven't been able to properly use it and know how well I can rely on it, can only go off of specs and reviews at this point. But if it does what it says, I'm impressed something so small can jump a truck.
The case, which is well padded and also holds the cables, etc, makes the space it takes in the truck relatively larger but even then it's still pretty small.
Amazon.com: TACKLIFE T8 800A Peak 18000mAh Lithium Car Jump Starter for Up to 7.0L Gas or 5.5L Diesel Engine, 12V Auto Battery Booster with LCD Screen, Portable Power Bank with USB Quick Charge: Automotive
Stock pics.
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My pics; here it is powering my CPAP as a test.
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And, for size comparison, being charged by a larger power station (which, ironically, can't power my CPAP via DC converter...)
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In its case...
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