NOCO Boost GB40 Review (2026)

Where to buy

Prices and stock change constantly, so we deliberately quote none here — the live Amazon AU listing always shows the current price. Links to Amazon AU may be affiliate links; qualifying purchases earn a commission at no extra cost to you.

Key specifications

What we like, and where it gives ground

What it is, and who it suits

The GB40 is a portable lithium jump starter. It is a small, charged pack with heavy clamps on the end. You clamp it to a flat car or 4WD battery, and it delivers a strong burst of current to crank the engine. No second vehicle, no crossing cables over two bonnets, no waiting for a good Samaritan.

This review answers one question. Is the GB40 the right jump-start safety piece for how you drive and tour in Australia? We have not put this unit through our own bench work, and we say so up front. Instead we read the maker's published specs against the jobs a 4WD, family car or roadside kit asks. Those jobs decide whether a gadget earns a spot.

If you range alone or want self-reliance at a flat battery, this is the shortlist pick. If you always have a helper and cables, you may not need it. The sections below take the pack apart piece by piece.

How it starts a flat battery

A flat battery has chemical energy but not enough current to turn a starter motor. The GB40 fills that gap. Its lithium cells dump a high peak current, quoted at around 1,000 amps, through the clamps straight to the battery terminals. That surge is enough to crank many petrol engines and get the alternator running.

The key limit is capacity, not just amps. The pack can give several jumps from one charge, then it needs recharging itself. It also cannot force a battery that is truly dead, damaged or sulphated back to life. In those cases the jump may fail, and no booster can fix a battery at the end of its life.

Used on a battery that is simply flat from lights or a short-spell park, it works quickly. The maker lists the engine sizes it suits, so check your vehicle is inside them before you rely on it on a remote day.

Spark-proof clamps and safety

Old jump-starting scares people for good reason: sparks near a battery can ignite the gas it gives off, and reversing the clamps can wreck electronics. The GB40 is built to reduce both risks. Its intelligent clamps will not spark if you touch them together, and they will not send current if you have the polarity wrong.

That safety is a real reason a novice or a family buys this rather than bare cables. It does not remove the need to read the instructions, though. You still fit the clamps to the correct terminals, keep the pack off the ground where it can get damp, and store it away from heat.

A 4WD with a dual-battery setup or extra electronics should be jumped with the maker's guidance in mind. If your rig is complex, learn the right point to connect before an emergency, not during one.

The extra features

Beyond jump-starting, the GB40 is a small emergency power hub. It has a built-in LED light with several modes, useful as a torch under a bonnet or a signal if you are broken down after dark. That alone is worth the drawer space to many drivers.

A USB output lets it top up a phone, a GPS or a headlamp. For a walker or a car camper, a pack that can revive a phone when your main battery is down adds quiet insurance. It is not a huge power bank, but it is a solid one that also jumps your vehicle.

None of this is the reason you buy it, but it turns a once-a-decade tool into something you are glad to carry even when the car starts fine on the 999 other days.

Storage and holding a charge

Lithium packs win on standby. The GB40 holds enough charge for months of sitting in a boot or a glovebox, so it is ready when you need it and you do not have to think about it. That long self-discharge grace is exactly what an emergency item should have.

That said, it is not infinite. Best practice is to top the pack up a couple of times a year, and always before a long trip. A booster that has quietly drained over a year in a hot cab is a booster that will fail when you reach for it.

Heat is the enemy of any lithium cell. Do not store it on a metal dashboard in a summer sun. A shaded side pocket or a storage box that stays cool keeps the pack healthier for longer.

Durability and value

The GB40 sits at the mass-market end of jump starters, and its value is that it brings a safe, capable booster to a fair price. Compared with the cost of a tow, a stranded day, or a call for help in remote country, a pack that lets you start yourself is cheap insurance you hope to use twice.

Build quality centres on the clamps and the cells. Treat the clamps gently, keep the ports clean, and store the pack within its temperature range, and it should serve for years of standby duty. It is a low-use item, so lifespan is mostly about cell care, not wear.

Against a set of jumper cables, the difference is self-reliance. Cables are cheaper and last forever, but they need a second car. For solo touring, that is the whole argument for the pack.

How it compares to other options

It helps to set the GB40 against the two ways people solve a flat battery. Each wins in a different situation, and the choice rests on whether you are ever alone.

Should you buy it?

Buy the GB40 if you tour, park for long spells, or simply want to fix a flat battery yourself instead of waiting. Its held charge, spark-proof clamps and power-bank extras make it a superb roadside safety piece for a family car or a light 4WD.

Skip it if you always have a helper and cables and never range alone. Check a bigger pack too if you run a large diesel, since the GB40's capacity is built for smaller engines.

Still deciding? See how it ranks in our 4WD recovery and safety gear guide. To fold it into a full roadside kit, our checklist generator builds the rest of the list around it.

Frequently asked questions

Will the NOCO GB40 jump a diesel 4WD?

The GB40 is built mainly for petrol engines and smaller vehicles, and NOCO lists the engine sizes each model suits. A large turbo-diesel can demand more starting current than the GB40 can reliably give, so a bigger NOCO pack is often the safer choice for a heavy diesel 4WD. Check the rated engine sizes on the listing against your vehicle before you rely on it out on a track.

How long does the GB40 hold its charge?

Lithium packs like this hold a usable charge for months sitting in a boot, which is what makes them good standby safety gear. It is not unlimited, though, and heat speeds the loss. The sensible habit is to top the pack up a couple of times a year and always before a long trip. Store it somewhere cool and shaded, not on a hot metal dashboard in summer sun.

Is the GB40 safe to use on modern electronics?

Its clamps are spark-proof and protected against reverse polarity, so they will not send current if you connect the wrong way, which is a big safety gain for nervous users. That said, always follow the maker's steps and fit the clamps to the correct terminals. On a 4WD with a dual-battery or complex electronics, learn the recommended connection point before you ever need it in the field.

Can the GB40 charge my phone?

Yes. Besides jump-starting, the pack has a USB output you can use to top up a phone, a GPS or a headlamp, plus a built-in LED light with several modes. It is not a huge power bank, but it is a solid one that can also start your car. Those extras make it worth the drawer space even on the many trips where the battery never goes flat.

Can a jump starter revive a dead battery?

It can start a car when the battery is simply flat from lights or a short park, by giving the burst of current the battery cannot. It cannot fix a battery that is truly dead, damaged or near the end of its life, and in those cases the jump may fail or hold only long enough to get you to a servo. A booster is a rescue tool, not a cure for an old battery.

Is the GB40 worth it over jumper cables?

For solo driving and touring, usually yes, because it makes you self-reliant. Cables are cheaper, never drain themselves and last forever, but they need a second car within reach, which a lonely track rarely offers. Many drivers keep both. If you often have a helper, cables may be enough. If you range alone, the held-charge convenience of the pack earns its price.