Compact, portable Jumpstarters are among the most civilized automotive inventions of the past decade or so—spurred by the rise of the lithium-ion battery over a previous generation of lead-acid devices. Suddenly, leaving your headlights on no longer means waiting two hours for a tow truck driver or begging strangers to hook up cables. Just pull out one of these little boxes, and go along your way.
This tiny 3000-amp A3 Gooloo jumpstarter, small enough to fit in a glove box, is the lowest-cost jumpstarter whose reliability I can personally vouch for. I've carried mine in multiple cars over the past couple of years, and it hasn't failed me. This A3 was able to jump a bone-dead battery twice in a row on my hulking ‘95 Land Cruiser, without being out of juice. The Gooloo A3 is nearly half off right now for Amazon Prime Big Deal Days, available at the eminently reasonable price of $70 ($60 off).
If what you actually want is a power bank to power all sorts of things, check out WIRED's guide to the best Power Bank Prime Day Deals, or look at many categories of useful (and cheap!) things in our Absolute Best Prime Big Deal Days picks, and our live blog of bargains and lightning deals.
This little A3 portable jumpstarter, which in many models also includes a tire inflator, is the model that's served me ever since the day I found myself stranded on an isolated stretch of Delaware, apparently impervious to cell phone signals. I was saved by a lone passing truck, whose driver happened to have a little portable Gooloo jumpstarter. A miracle!
I drove directly to an auto store, bought this little A3, and never looked back. Its 3000A peak amperage is quite a lot for its price, and more than high enough to juice most personal vehicles. It's rated for gas engines up to 9 liters and diesel up to 6 liters, with standard 12-volt batteries.
Higher peak amps do not always mean better performance or durability, and so I'll soon be testing multiple additional models from Gooloo and other makers—including Gooloo's well-regarded 6000-amp GT6000 jumpstarter, which is also on sale for $136 ($34 off).
If I had a large diesel or lived in very cold climates, I'd probably opt for higher-amp devices out of caution. Also note that for fully dead batteries, you'll need to use the “boost” function on the device to get a charge, and that the clamps might be a bit short and stubby for some battery or car designs.
Former WIRED reviewer Eric Ravenscraft has also had terrific luck with the 1000-amp Boost Plus jumpstarter from well-regarded brand Noco, which should also be powerful enough for most commuter cars. That Noco is also on sale, sitting below $100.
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