NOCO Boost GB20 jump starter review

Overview

The NOCO Boost GB20 is a compact lithium jump starter for drivers who want an emergency back-up for a smaller petrol car or motorcycle. It ranks #6 in our list of the top 10 best-selling portable jump starters on Amazon UK and scores 8.6/10, earning our Best for small petrol cars award. Its 500A peak output is rated for petrol engines up to 4.0 litres; the listing says it is not recommended for diesel engines, so check your vehicle before buying. Compared with the NOCO Boost GB40 at #3, the GB20 is the lower-cost option for smaller petrol engines. The #7 Ring UltraBoost 1500A is another alternative in the list, but the GB20’s appeal is its compact size and straightforward emergency role.

Features and specification

The GB20 measures 20.8 x 11.7 x 10.7cm and weighs 454g, making it easier to store in a glovebox or emergency kit than a larger jump pack. NOCO claims up to 20 starts per charge, though actual results can vary with battery condition, engine demands and how often the pack is used. The listing says it recharges in around three hours.

Its safety features include spark-proof connections and reverse-polarity protection, which are intended to help prevent operation when the clamps are connected incorrectly. It also doubles as a USB power bank and has a 100-lumen LED torch with seven modes, including SOS and strobe. The housing is rated IP65 for resistance to dust and water jets, and the box includes heavy-duty clamps, a USB-C charging cable and a storage bag. A one-year warranty is listed. These extras are useful in an emergency, but the GB20 is not a replacement for a dedicated battery charger or a higher-output booster for vehicles beyond its stated engine limit.

What owners say

Owners commonly praise how small and light the unit is, especially when keeping it in a car or carrying it on a motorcycle. Reviews describe it starting vehicles after a flat battery and being simpler to manage than arranging a jump from another car. Some motorbike owners also find it handy for occasional battery trouble. These are individual reports rather than a guarantee for every vehicle or battery condition.

There are practical caveats: one owner found the connector needed to be pushed fully into place before the unit worked, while another reported needing to recharge after several starts during repeated use. It is sensible to check the charge periodically and follow the instructions for connecting the clamps. Independent retailer reviews also describe the GB20 as compact and easy to use, but its small size does not remove the need to match it to the vehicle.

Who should buy it

The GB20 is a sensible choice for drivers of small petrol cars and riders who want a light, easy-to-store emergency booster, plus a torch and phone-charging backup. It may suit people who would rather carry a self-contained pack than rely on another vehicle for a jump-start. The listing’s up-to-4.0-litre petrol limit and up-to-20-start claim are specifications, not promises for every situation.

Skip it if your vehicle is diesel or has an engine larger than the stated petrol limit. It is also a less suitable choice if you expect frequent jump-starts or need a pack for larger vehicles; consider a higher-capacity model from the list instead. For occasional back-up in a compatible petrol car or on a motorcycle, the GB20’s portability and safety features make it a useful, focused option.