A well-rounded, compact booster with strong owner feedback and useful protection features for everyday cars.
Pros
- Compact, portable format with a storage bag
- Spark-proof and reverse-polarity protection
- USB power bank and 100-lumen torch
- Rated for up to 6.0L petrol and 3.0L diesel engines
Cons
- No numeric display for remaining charge
- Not the best choice for larger diesels or failed batteries
- Clamp lead reach may be limiting in some engine bays
Overview
The NOCO Boost GB40 is a portable 12V jump starter aimed at drivers who want backup for everyday cars without carrying a bulky unit. It ranks #3 in our list of the top 10 best-selling portable jump starters on Amazon UK, with a score of 8.8/10. The listing rates it for petrol engines up to 6.0 litres and diesels up to 3.0 litres. It sits below the premium NOCO Boost GB70, our best overall pick, and above the budget TREKURE 5000A. The GB40 is a sensible middle ground: a well-known brand and useful safety features, without being the top-ranked option or a budget choice.
Features and specification
Its stated peak current is 1,000A, and the listing claims up to 20 starts per charge. Treat that figure as a best-case claim: the number of starts will depend on factors such as the vehicle, battery condition and charge remaining in the pack. Spark-proof and reverse-polarity protection are designed to reduce the risk of incorrect connections, while the heavy-duty clamps connect to the vehicle battery or a suitable grounding point.
The GB40 also works as a USB power bank and includes a 100-lumen LED torch with seven modes, including SOS and strobe. Its housing is rated IP65 for dust and water resistance, and the listing says it recharges in around three hours. It comes with a charging cable, clamps and a storage bag, plus a one-year warranty. One trade-off is the lack of a numeric screen showing the remaining charge; its indicators are less detailed than a percentage display.
What owners say
Owners commonly report that the GB40 is straightforward to connect and has started petrol cars and moderate-sized diesels when their 12V batteries were flat. Several describe it as compact enough to keep in a car, with the bag and built-in torch adding practical value. Some also appreciate being able to use it for charging a phone or taking it camping.
There are limits. A jump starter cannot fix a battery that has failed completely, and one owner reports difficulty with a diesel that regularly went flat. Some buyers advise checking and topping up the unit’s charge during storage so it is ready for an emergency. A few find the clamp leads short for awkward battery layouts, although others say the reach is adequate for their cars.
Who should buy it
The GB40 is a good fit for drivers who want a reputable, compact booster for routine emergencies in a petrol car or moderate-sized diesel, and value connection protection as well as a torch and USB output. It is also a useful option for occasional camping or keeping in a boot as backup. If you regularly need to start a large diesel, want more headroom, or prefer a clear numerical charge display, consider a more powerful model or one with a screen instead. As with any jump starter, keep it charged and follow the vehicle and device instructions.
What UK owners say
Owners like
- Often reported to start everyday petrol cars and moderate-sized diesels
- Compact size makes it easy to store and carry
- Simple connections, torch and USB output add useful convenience
Common complaints
- Some owners recommend checking and replenishing its charge during storage
- A few report limited success with particularly demanding or deeply discharged batteries
- Some find the clamp leads short for awkward battery layouts
Summarised in our own words from recurring themes in verified Amazon.co.uk reviews.
Key specifications
| Peak current | 1,000A |
|---|---|
| Engine capacity | Up to 6.0L petrol / 3.0L diesel |
| Starts per charge | Up to 20, according to the listing |
| Protection | Spark-proof and reverse-polarity protection |
| Extra functions | USB power bank and 100-lumen LED torch |
| Ingress rating | IP65 |
Taken from the manufacturer's Amazon listing. Check the listing for the latest details.
The verdict: 8.8/10
The NOCO Boost GB40 is worth considering for drivers who want a compact, safety-focused jump starter for everyday cars, with handy extras and strong owner feedback. Skip it if you need extra capacity for a large diesel or want a numeric charge display; a higher-capacity or screen-equipped model may suit you better.
Best for: Drivers seeking a reputable, portable jump starter for petrol cars and moderate-sized diesels. Skip it if: You need extra headroom for a large diesel, or want a display showing the remaining charge.
See it on Amazon.co.uk