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Frequently Asked Questions
How many amps do I need in a jump starter?
For most gas cars and crossovers, 1000A peak (the GB40’s rating) is enough for engines up to 6.0L — this noco boost jump starter covers the common cases. Go bigger if you have a large V8 or a diesel — match the unit’s engine rating to your vehicle, not just the amp number.
Can the NOCO GB40 start a diesel truck?
Only small diesels up to 3.0L. For larger diesel trucks, NOCO rates the bigger GB70 up to 6.0L diesel. Check your engine’s displacement before buying.
How long does the GB40 hold its charge?
Lithium jump starters hold their charge well in storage — NOCO’s documentation notes the pack stays ready for extended periods, but it is smart to check the charge LEDs every few months and top it up before winter and road trips.
Is it safe to use on modern cars with sensitive electronics?
The GB40’s spark-proof and reverse-polarity protections are designed to make hookups safer. Still, always follow your vehicle’s owner manual — some manufacturers have specific jump-starting procedures for their electronics.
Can I bring a lithium jump starter on a plane?
Lithium batteries in carry-on luggage are subject to airline watt-hour limits. The GB40’s 24Wh internal battery is well under the common 100Wh carry-on threshold, but always check your airline’s current dangerous-goods policy before flying.
Does the GB40 work as a phone charger?
Yes. Its USB output (5V, 2.1A) can recharge phones, tablets, and other USB devices, so it doubles as a portable power bank in an emergency.
NOCO Boost GB40 Jump Starter Review: Is the 1000A Classic Still Worth It?
A dead battery always picks the worst moment: a cold morning, a dark parking lot, or the middle of a road trip. This NOCO Boost jump starter review looks at the GB40, the 1000-amp portable jump starter that made glovebox-sized jump packs mainstream, and lays out exactly what it can and cannot do — so you can decide if it fits your car before you buy.
The GB40 is built for one job: restarting a dead 12-volt battery without a second car. The need is real — AAA reported roughly 7 million battery-related roadside assistance calls in the US in 2024, making dead batteries one of the most common reasons drivers get stranded (source: AAA newsroom). NOCO rates the GB40 for gasoline engines up to 6.0 liters and diesel engines up to 3.0 liters, and says a single charge can deliver up to 20 jump starts (source: NOCO GB40 product page). That covers most sedans, crossovers, SUVs, and light trucks on US roads.
Top 3 Quick Picks
| Pick | Product | Key Spec |
|---|---|---|
| Overall Winner | NOCO Boost GB40 1000A Portable Lithium Jump Starter | 1000A peak, up to 20 jump starts per charge, gas up to 6.0L / diesel 3.0L |
| Best Budget | OXILAM 6000A Portable Jump Starter | 6000A peak, up to 60 jumps per charge, LED battery display |
| Premium Pick | NOCO Boost GB70 2000A Portable Jump Starter | 2000A peak, up to 40 jump starts, gas up to 8.0L / diesel 6.0L |
The short answer: The NOCO Boost GB40 is a 1000-amp portable lithium jump starter that jump-starts dead 12V batteries in seconds. NOCO rates it for gas engines up to 6.0L and diesel engines up to 3.0L, with up to 20 jump starts per charge, and it doubles as a USB power bank with a 100-lumen LED flashlight. It is a solid fit for most cars, SUVs, and light trucks — but not for large diesel trucks or big V8 work engines.
What the NOCO Boost GB40 Is
The GB40 is a noco boost jump starter that’s part of NOCO’s Boost line of UltraSafe lithium jump starters. It is a compact battery pack with built-in jumper clamps that replaces the old routine of flagging down a stranger for a jump. Connect the clamps to the dead battery, start the car, disconnect — no second vehicle needed.
The noco boost jump starter’s “UltraSafe” branding refers to its built-in protections: spark-proof connections and reverse-polarity protection, which guard against the two most common mistakes when hooking up jumper cables (source: NOCO GB40 product page). That makes it approachable for drivers who have never jump-started a car before.
NOCO Boost GB40 Key Specs
| Spec | GB40 (per NOCO) |
|---|---|
| Peak current | 1000A |
| Gas engine rating | Up to 6.0L |
| Diesel engine rating | Up to 3.0L |
| Battery type | 12V lead-acid (single-battery systems) |
| Jump starts per charge | Up to 20 |
| Internal battery | 24Wh lithium-ion |
| Energy rating | 7,000 joules (3S) |
| USB input | 5V, 2.1A |
| USB output | 5V, 2.1A (charges phones, tablets) |
| LED flashlight | 100 lumens, 7 modes incl. SOS and strobe |
| Housing | IP65 (with ports closed) |
| Weight | 1.65 lbs (0.74 kg) |
| Operating temperature | -4°F to +122°F (-20°C to +50°C) |
Sources: NOCO GB40 product page; NOCO GB40 data sheet (PDF).
Engine Compatibility: Will It Start Your Car?
This is the question that matters most. NOCO rates the GB40 for gasoline engines up to 6.0 liters and diesel engines up to 3.0 liters, for 12-volt lead-acid batteries in single-battery systems (source: NOCO GB40 product page).
In practice, that covers:
- Most 4-cylinder and 6-cylinder sedans and hatchbacks
- Most crossovers and midsize SUVs
- Many half-ton pickups with gas V8s under 6.0L
- Motorcycles, ATVs, boats, and lawn equipment with 12V batteries
It does not cover large diesel trucks, heavy-duty pickups with big diesels, or any engine above those displacement limits. If your diesel is over 3.0L, step up to the GB70 (rated to 6.0L diesel) or a larger unit. Matching the rating to your engine is the single most important buying decision here — an undersized noco boost jump starter is the most common reason a jump fails.
Safety Features Worth Knowing
Jump-starting involves real current, so the safety design of a noco boost jump starter matters as much as the amps:
- Spark-proof technology — no sparks when the clamps touch the terminals, reducing ignition risk around a battery.
- Reverse-polarity protection — if you clip red to negative by mistake, the unit protects itself and the vehicle instead of shorting.
- IP65-rated housing (with ports closed) — dust-tight and resistant to water spray, so rain on the roadside is not a crisis.
- 7,000-joule energy rating — the published energy figure behind the 1000A peak claim.
A general safety rule that applies to any jump starter: connect red to the positive (+) terminal first, then black to an unpainted metal ground point away from the battery; start the vehicle; remove the clamps promptly; and never let the clamps touch each other. Work in a ventilated area, since charging batteries can vent hydrogen gas.
Battery, Charging, and Extras
The GB40’s internal battery is a 24Wh lithium-ion pack — small enough to live in a glovebox or trunk organizer year-round. NOCO says it delivers up to 20 jump starts on a single charge, and lithium packs hold their charge well in storage, so a unit charged and stowed stays ready for months (source: NOCO GB40 product page).
Beyond jumping, this noco boost jump starter works as a portable power bank: the USB output (5V, 2.1A) can recharge a phone or tablet, which is genuinely useful if you are stranded with a dying phone. The unit itself recharges from any powered USB port at 2.1A.
The 100-lumen LED flashlight has seven modes, including SOS and emergency strobe. One hundred lumens is modest next to a dedicated flashlight, but it is enough to see battery terminals in the dark or signal for help — and it is always with the unit, which is the point.
Like any battery, the GB40 benefits from basic care: keep it reasonably charged in storage and avoid extreme heat. For the car’s own battery, regular car battery maintenance (clean terminals, secure mounting, periodic testing) prevents most no-start mornings in the first place.
How to Use a NOCO Boost GB40 Safely
These are the standard steps for your noco boost jump starter per NOCO’s documentation; always follow the user guide that ships with your unit:
- Charge the GB40 before you need it, and check its charge level periodically in storage.
- Connect red to positive (+) on the dead battery; connect black to a ground point — an unpainted metal part of the engine block or chassis, away from the battery.
- Start the vehicle. If it does not start within a few seconds, stop, wait, and try again rather than cranking continuously.
- Disconnect promptly once the engine is running: black first, then red. Do not leave the unit connected.
- Drive or run the engine long enough to let the alternator recharge the battery, and have the battery tested soon — a battery that died once often needs replacement.
Never jump a battery that is visibly cracked, leaking, or frozen. If the vehicle has electronics warnings against jump-starting in the owner’s manual, follow the manual.
Who Should (and Shouldn’t) Buy It
Good fit for:
- Daily drivers with a gas car, crossover, or SUV under 6.0L who want roadside self-reliance
- Road-trippers and commuters who park outdoors in winter
- Anyone who has ever waited an hour for a jump — the GB40 removes that dependency
- Drivers who also want a backup phone charger in the car
Not the right pick if:
- You drive a large diesel (over 3.0L) — look at the GB70 or larger
- Your vehicle has a 24V system or dual batteries — this is a 12V single-battery unit
- You want a maintainer for a stored car — a home battery charger is the right tool for that job, not a jump starter
NOCO Boost GB40 vs Alternatives
| NOCO Boost GB40 (Overall Winner) | OXILAM 6000A (Best Budget) | NOCO Boost GB70 (Premium Pick) | |
|---|---|---|---|
| Peak current | 1000A | 6000A (per listing) | 2000A |
| Gas rating | Up to 6.0L | All gas (per listing) | Up to 8.0L |
| Diesel rating | Up to 3.0L | Up to 12L (per listing) | Up to 6.0L |
| Starts per charge | Up to 20 | Up to 60 (per listing) | Up to 40 |
| LED flashlight | 100 lumens, 7 modes | 800 lumens, 3 modes (per listing) | 400 lumens |
| Display | Charge LEDs | Digital display | Charge LEDs |
| Brand track record | Established US brand | Newer value brand | Established US brand |
| Button | Check Price on Amazon | Check Price on Amazon | Check Price on Amazon |
GB40 specs: NOCO. GB70 specs: Amazon listing / NOCO line specs (2000A, 8.0L gas, 6.0L diesel, up to 40 starts, 400-lumen LED, IP65). OXILAM specs: Amazon listing (6000A peak, up to 60 jumps, 800-lumen LED, 10 safety protections).
A note on the numbers: peak-amp claims vary wildly between brands and are not measured to a single common standard, so treat cross-brand amp comparisons as rough. NOCO’s engine-displacement ratings are the more practical comparison point — they tell you directly what the unit is designed to start.
For a wider field of options, see our roundup of the best portable car jump starters.
The Bottom Line
The NOCO Boost GB40, a reliable noco boost jump starter, earns its reputation the boring way: it covers the vehicles most people actually drive, it is rated for up to 20 jump starts per charge, and its spark-proof and reverse-polarity protections make it forgiving for first-time users. Check that your engine falls within its 6.0L gas / 3.0L diesel ratings, keep it charged in the trunk, and you will likely never wait for a stranger with cables again.
If you are shopping around a sale season, also check the seasonal jump starter deals — prices on popular units move around holidays.
