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The NOCO Boost Plus GB40 is the jump starter most drivers should size against first. It packs 1,000 peak amps into a 2.4-pound, glovebox-sized package rated for gas engines up to 6.0 liters and diesels up to 3.0 liters. In independent testing by TechGearLab, it restarted a drained 4.0-liter V6 three times in a row in cold weather. That’s the exact bad morning it exists for. Buy it as a dedicated rescue tool for a sedan, crossover, or half-ton truck. Look elsewhere if you want a power bank that moonlights as a jump starter, or if you drive a larger diesel.
I’ve kept a jump pack in every truck and farm rig I’ve driven through winters cold enough to kill a battery overnight. The ones that earn a spot in the glovebox are sized to the engine, not loaded with extra gadgets.
NOCO GB40 at a Glance
| Peak output | 1,000 amps (12V lithium) |
| Engine rating | Gas up to 6.0L, diesel up to 3.0L |
| Size and weight | 6″ × 3″ × 1.5″, 2.4 lbs |
| Safety features | Spark-proof, reverse-polarity protection, IP65 water resistance |
| List price | $125 (often discounted at major retailers) |
| Best for | Sedans, crossovers, minivans, and most gas trucks |
The test result that matters
A jump starter has one job, and it usually gets asked to do that job cold. In TechGearLab’s testing, the GB40 successfully jump-started a midsize 2010 Ford Explorer with a 4.0-liter V6 and a drained battery. It did that three consecutive times in cold weather, passing the outlet’s rapid-restart test. That repeatability is the spec that no box copy prints. One start gets you to work, but three starts in a row means the unit still has margin when the first attempt doesn’t take.
The same testing kept the GB40 honest on capacity. NOCO claims 24 watt-hours; TechGearLab measured 15.57 usable watt-hours. That gap matters less for jump-starting, since starts draw brief bursts, not deep capacity. But it is one reason this unit makes a mediocre phone-charging power bank, which we get to below.
Will it start your vehicle? The engine-fit chart
NOCO’s rating — gas to 6.0 liters, diesel to 3.0 liters — is abstract until you map it onto real driveways. We built that map. The table below places common vehicle classes against the GB40’s rating so you can find your own car in one pass. It is our own analysis computed from the manufacturer’s displacement rating, not a list of vehicles NOCO has individually endorsed.
| What you drive | Typical engine size | GB40 fit |
|---|---|---|
| Compact and midsize sedans (Civic, Camry) | 1.5–2.5L gas | Comfortably within rating |
| Crossovers and minivans (RAV4, Odyssey) | 2.0–3.5L gas | Comfortably within rating |
| V8 half-ton pickups and large SUVs (F-150 5.0L, Tahoe 5.3L) | 5.0–5.7L gas | Within rating, less headroom — frequent cold starts favor a bigger unit |
| Big-block gas trucks and RVs | Over 6.0L gas | Outside rating — size up (e.g., NOCO’s larger Boost models) |
| Compact diesel cars and SUVs | 2.0–3.0L diesel | Within rating |
| Heavy-duty diesel pickups (6.6–6.7L) | Over 3.0L diesel | Outside rating — size up |
The honest summary: the GB40 covers the overwhelming majority of gas daily drivers, gets thinner near the top of its range, and is the wrong buy for heavy-duty diesels. Overbuying capacity is cheap insurance; overdrawing an undersized unit on a February morning is not.
Living with it: clamps, charging, and the six-month rule
TechGearLab’s reviewers praised the build specifics that matter mid-emergency. High-quality clamps with strong grip, an over-molded rugged casing, and an IP65 rating that shrugs off rain and dusty trunk floors all stood out. Spark-proof terminals and reverse-polarity protection mean a wrong-way connection refuses to arc rather than punishing the mistake. The right procedure is always the one in NOCO’s manual and your vehicle’s owner handbook, so read both before your first use. Call a professional if a battery is damaged, leaking, or repeatedly dying.
Ownership has one recurring chore: charge discipline. The GB40 recharges from empty in about 3 hours over USB-C. Lithium jump starters also self-discharge slowly in storage, so put a twice-a-year top-up on your calendar; daylight-saving weekends are an easy anchor. A jump starter that lived uncharged in a trunk for two years is just a paperweight with clamps.
Where it falls short
Three flaws, none disqualifying. First, no storage case is included at a $125 list price — an odd omission when the clamps and cable want corralling in a trunk. Second, USB output tops out at a slow 10 watts. With roughly 15.6 measured watt-hours aboard, this is an emergency phone top-up, not a road-trip power bank. TechGearLab scored it below other NOCO models on exactly this point. Third, the built-in flashlight is serviceable for finding battery terminals and little else.
Notice what is not on that list: starting performance. The complaints cluster around the accessory features, which is the right place for a rescue tool’s compromises to live.
Verdict: Who Should Buy the NOCO GB40
After running jump packs through cold-morning truck starts for years, the NOCO Boost Plus GB40 is the one I would hand a friend with a sedan or half-ton truck, because it’s sized right for that range. Buy it if you drive anything from a compact up through a typical V8 half-ton and want a set-and-forget rescue tool that starts the car when the battery won’t. Size up to a higher-amperage model if you drive a big-block gas engine or any diesel over 3.0 liters. The same goes if you routinely face deep-winter cold starts at the edge of the rating. Skip the category’s power-bank hybrids if what you really want is phone charging. Dedicated power banks do that job better, and the GB40 does its one job better than they ever will.
A jump starter is one leg of a three-legged roadside kit. Our car emergency kit guide covers the rest, and a cordless tire inflator handles the other most common stranding. If you are outfitting the car in one go, our dash cam guide rounds out the trio.
How We Researched the NOCO GB40
We verified every specification and test figure in this review against NOCO’s published product information and TechGearLab’s independent instrumented testing, including its measured-capacity and cold-start results. The engine-fit chart is our own analysis computed from the manufacturer’s displacement ratings. We do not claim hands-on testing. We weight repeatable measured results and long-term owner feedback over launch-week impressions instead, and the full process is in our editorial standards. Prices are approximate, current as of publication, and change frequently — confirm the latest price with the retailer before buying.
Published July 22, 2026. Updated September 8, 2026.
NOCO GB40 FAQ
What size engines can the NOCO GB40 jump-start?
NOCO rates the GB40 for gasoline engines up to 6.0 liters and diesel engines up to 3.0 liters. That covers most sedans, crossovers, minivans, and half-ton gas trucks, but not big-block gas engines or heavy-duty diesels.
How many jump starts can the GB40 do on one charge?
In TechGearLab’s independent testing, a charged GB40 restarted a drained 4.0-liter V6 three consecutive times in cold weather. Real-world counts vary with engine size and temperature, so recharge it after any use rather than banking on leftover capacity.
How often should I recharge a stored jump starter?
Top it up about every six months in storage and after every use. The GB40 recharges from empty in roughly 3 hours over USB-C, and a twice-yearly calendar reminder keeps it ready for the morning it’s actually needed.
More gear that earns its spot in the console lives in our Smart Car Gadgets section.
