Best jump starters: Revive your battery with a portable power pack
How to choose the best jump starters to get your car running
We’ve all been there. You turn the key in your car’s ignition, and there’s a tell-tale sound of an engine struggling to turn over because the battery is flat. In fact, the AA says a flat or faulty battery is the number one reason for a call-out. It’s inconvenient, and depending on your breakdown cover, potentially expensive, too. Slip one of the best jump starters into your boot or glove compartment, though, and you can save yourself all that hassle.
These jump starters, sometimes called jump packs, have largely replaced jump leads, because they’re compact, efficient, easy to use and don’t require another car to be on standby to provide a surrogate battery. You simply connect the clamps to your car’s battery terminals following the instructions, start your car in the normal way and disconnect them.
Jump starters rely on the latest battery technology, so can be compact and charge from the mains – or even from your car’s 12-volt socket in some cases, even if a full charge will take a while. Many also offer additional features, such as providing a handy power source if you’re camping or fishing, for charging phones or other devices via USB sockets, or lighting up your surroundings with a torch. Others can act as a compressor or include an inverter with a three-pin household plug socket.
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Best jump starters: At a glance
- Best-value jump starter: Halfords Advanced Lithium Jump Starter | £61
- Best jump starter for range of features: Halfords 6-in-1 Jump Starter Power Pack | £100
- Best jump starter for big engines: Micro-Start XP-10 | £240
How to buy the right jump starter for you
Are jump starters portable?
Yes. You can think of jump starters as a portable battery in a box. They can be the size of a tablet computer up to the size of a cereal box, depending on the features the jump starter has and the type of battery technology it uses. Size really doesn’t matter when it comes to jump starters – many of the best are tiny, yet can start huge engines.
Do jump starters go flat?
Pretty much anything with a battery will eventually go flat, but the beauty of a jump starter is that you can charge it from home, chuck it in the boot of your car and forget about it until you really need it. You can certainly expect most jump starters to last six months laying dormant in your car before needing a charge.
What do amps mean on a jump starter?
When you’re choosing a jump starter, particularly one that may need to start a big, heavy engine, you’ll need to consider the amount of amps (or milliamps) it can supply.
An amp is a measurement of the amount of electricity that can flow through a circuit: the more amps a jump starter can provide, the more oomph it will have to start an engine. Amps will be displayed as Ah, milliamps as mAh – milliamps are simply amps divided by 1,000, so 5Ah is equivalent to 5,000mAh.
Usually, jump starters will have a maximum engine size they can start; most will easily handle two-litre engines, but some can crank over four-litre engines or even more. Just remember that diesel engines usually require more power than petrol engines to get them started.
Can I use a jump starter on a car with a start-stop system?
Most modern cars feature start-stop technology, which cuts the engine when the vehicle is stationary and fires the engine when you dip the clutch in a manual or press the accelerator in an automatic. Cars with this technology use Absorbent Glass Mat (AGM) batteries rather than conventional lead-acid items – use the wrong jump starter and you could seriously damage the battery.
Do jump starters charge a battery?
In effect, jump starters allow power to be drawn through the battery to the car’s ignition system, but not enough to charge the battery in the traditional sense. Once the engine is running, the car will begin to charge the battery itself, so once you remove the jump starter’s clamps from the battery, keep the engine running for 30 minutes or more to ensure the battery is charged enough to allow the next engine restart.
How we test jump starters
We examined the technical specifications of the jump starters in our test to ensure their suitability for the majority of motorists. We were primarily looking for a balance between price and electrical punch because, while a jump starter is rarely used, it’s important to know that it will do the job when you need it, and yet there’s little point in paying for aspects you’re unlikely to use.
We took note of the depth of detail and legibility of the instructions, and used each device to jump start a 1.6-litre Ford Focus with a flat battery a total of five times, with a gap of two minutes in between. Afterwards, we noted how much of the battery power had been consumed by recording how many lights had been extinguished. The general ease of use and the length of the included cables played a large part in our assessment, alongside features such as alerts – should the terminal clamps be connected incorrectly, for example.
Additional features were assessed and highlighted in our roundup; however, these didn’t directly affect our judgement, primarily due to the range of devices we were testing. For example, it would be unfair to criticise a glovebox-sized jump starter for not incorporating a tyre inflator.
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The best jump starters you can buy in 2023
1. Halfords Advanced Lithium Jump Starter: Best-value jump starter
Price when reviewed: £61 | Check price at Halfords
This compact, well-priced jump starter from Halfords gets everything right. It’s simple to use, has clear instructions printed on the box rather than in a pamphlet that’s likely to get lost, and clear charge indicators. There’s no ambiguity over the size of engine it’s capable of turning over, either, because the clue is in the name.
The unit is small enough to fit in your glovebox or place on top of the car’s battery when jump starting, meaning there’s little risk of it falling as the engine starts. The jump leads plug in the side, and there are green and red lights to show whether or not the leads are correctly connected to the battery terminals. There are four bright blue LED indicators on the unit showing charge at 25% increments, and a bright LED light that’s useful if you’re jump starting in the dark. A USB socket allows you to charge phones or other devices, which will provide extra reassurance in an emergency.
It easily started our car five times, and came out of the test registering a full 100% charge remaining. If we’re being picky, we’d like the leads to be a little longer than their 28cm from plug to clamp, and the leads feel a little lightweight, but it’s hard to be critical at this price. What blots the copybook is that it only comes with a USB charging cable; there’s no mains adapter in the box, so you’ll need to provide your own if you want to charge it from the mains.
Key specs – Battery capacity: 6,000mAh; Peak amps: 300A; Suitable for: Up to 2.0 litres; Additional features: LED torch, USB socket, USB charging lead
2. Halfords 6-in-1 Jump Starter Power Pack: Best jump starter for range of features
Price when reviewed: £100 | Check price at Halfords
Halfords’ 6-in-1 jump starter is big on size, big on features but also big on weight. But there’s not a lot it won’t do: it will pump tyres to 150 PSI, and power devices running on 12-volt DC as well as those fed by a USB cable. It has a bright LED light, but perhaps most impressively has a 100-watt mains inverter that allows you to run 240-volt devices.
Despite the range of features, it’s remarkably easy to use. A sliding switch allows you to select the LED light or USB power, the 12-volt cigarette-lighter socket is covered by a rubber flap and the tyre compressor hose and adaptors stow in the back of the unit, near the pressure gauge. You simply plug in a three-pin plug and switch the device on to use the inverter. It could make an excellent camping companion.
The jump starter is slightly more cumbersome, mainly because of the weight and the leads, which are slightly too short to guarantee a steady placement around the engine, so you might want to ask someone to hold it steady while you start the car.
To use, it’s a case of connecting the clamps to the battery, checking the green light illuminates to show everything is correctly connected, turning the on/off knob and starting the engine. After our five starts, the 6-in-1 still registered a full charge with all of its four LEDs illuminated.
Key specs – Battery capacity: 17,000mAh; Peak amps: 650A; Suitable for: Up to 2.0 litres; Additional features: Air compressor, LED light, USB socket, 100W mains inverter, 12V DC socket, mains charger
3. Micro-Start XP-10: Best jump starter for big engines
Price when reviewed: £240 | Check price at Track Formula 
With the ability to start petrol and diesel engines up to 4.5-litres in capacity, the XP-10 is a small unit capable of big things. And with a range of sockets and adaptors, it’s capable of providing power to all manner of laptops, tablets, phones, cameras and other USB devices. In fact, it might be as useful as a portable power supply as it is for starting cars and vans, especially as the jump starter and accessories can all be kept safe in its tough, zip-up case.
The power pack is finished in a grippy material that makes it easy to hold. To jump start a vehicle, you simply connect the jump lead assembly to the power pack and attach the clamps to the car battery, checking the green light illuminates to ensure you’ve done it correctly, then start the car.
In our test, the XP-10 lost one of its LEDs, but it’s likely the five lights here offer more granularity than the four lights of the other units on test. Micro-Start says it should be able to start around 50 four- or six-cylinder engines on a charge; far less if you’re trying to crank a 6.0-litre diesel, which is the unit’s maximum. It’s an excellent piece of kit, but you’ll need to exploit its huge potential as a power pack to justify the premium price.
Key specs – Battery capacity: 18,000mAh; Peak amps: 600A; Suitable for: Up to 6.0-litres; Additional features: LED light with solid, flashing and strobing modes, 2x DC outputs, 2x USB outputs, multiple DC and USB adaptor tips, mains and 12V chargers
