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03 — Road Trip / Roundup

Best portable jump starters

Peak amps is the number on the box and the least useful number there is. Engine size rating is the spec that tells you whether a jump starter will actually start your car.

By Brijon M.Last updated How we pick
Portable power equipment packed in the back of a vehicle

The short answer

The NOCO Boost Plus GB40 is the pick for most drivers: 1,000 amps, rated for gas engines up to 6 liters, and small enough to live in a glovebox. If you drive a diesel, a V8 truck or a van, step up to the NOCO Boost Pro GB70, which is rated to 8 liters gas and 6 liters diesel.

Trail & Terminal earns a commission when you buy through our Amazon links, at no extra cost to you. It does not change which products we pick -- see our affiliate disclosure and selection method.

Our picks at a glance

Best portable jump starters -- ranked picks
#ProductBest forKey specPrice
1NOCO Boost Plus GB40The default recommendation. Rated for the engines most people actually drive, genuinely pocketable, and the safety design is the real reason to buy it.most cars and small SUVs1,000 A peak, 6 L gas / 3 L diesel, 2.4 lb
2NOCO Boost Pro GB70Twice the current and a rating that covers a 6-liter diesel. Heavier, and the right answer if you drive anything big.trucks, vans and diesels2,000 A peak, 8 L gas / 6 L diesel, 4.18 lb
3HULKMAN Alpha 85A 3.3-inch screen that tells you what is happening, 2,000 amps, and an hour to 80 percent. The best-informed jump start here.a real display and fast recharging2,000 A peak, 20,000 mAh, 8.5 L gas / 6 L diesel
4NOCO Boost Sport GB20500 amps and barely two pounds. The right size for a small car or a bike, and the wrong size for anything else.small engines, motorcycles and a glovebox500 A peak, up to 4 L gas, 2.1 lb
5GOOLOO GT15001,500 amps claimed, light, and a lot of capability for the money -- from a brand with less of a safety reputation behind it.the budget pick1,500 A claimed, 8 L gas / 6 L diesel claimed, 2.31 lb

Ranked by the criteria in how we pick. We hold no live prices, so every button goes straight to the current Amazon listing.

Every pick, in full

The picks

1

Best for most cars and small SUVs

NOCO Boost Plus GB40

The default recommendation. Rated for the engines most people actually drive, genuinely pocketable, and the safety design is the real reason to buy it.

This is the one to buy unless you know you need more, and the reason is the safety design rather than the amps. The failure mode of jumper cables is a person connecting them backward in the dark and destroying an alternator or a battery. This unit will not pass current until the clamps are on correctly, and it does not spark when they touch. That turns a job most people do badly into a job they cannot easily get wrong.

The size matters almost as much. A jump starter in a garage is a jump starter you do not have when the car will not start in an office parking lot, and this one fits a glovebox alongside the manual. For the broader kit a car should carry, see our road trip essentials list.

Specs

  • 1,000 amp peak rating; NOCO rates it for gas engines up to 6 liters and diesel up to 3 liters
  • 2.4 lb; 6.7 x 3.2 x 1.7 inches
  • IP65 rated with the ports closed
  • Operating temperature range given as -30 C to +50 C (about -22 F to 122 F)
  • USB output 5 V / 2.1 A, so it doubles as a small phone charger

Good for

  • Spark-proof design and reverse-polarity protection -- it simply will not deliver current if the clamps are wrong
  • Small and light enough that it stays in the car, which is the only place a jump starter is useful
  • The rated operating range covers genuinely cold mornings, which is when you need it

Bad at

  • 1,000 amps is not enough for a large diesel, a big V8 or a deeply discharged battery in hard cold
  • Micro-USB input means slow recharging and an obsolete cable to keep track of
  • The internal battery is small, so it is a poor phone power bank compared to a dedicated one
2

Best for trucks, vans and diesels

NOCO Boost Pro GB70

Twice the current and a rating that covers a 6-liter diesel. Heavier, and the right answer if you drive anything big.

The honest version of the upgrade case: cranking a cold diesel is a fundamentally harder electrical job than cranking a warm four-cylinder, because diesels need to turn over against much higher compression and often use two batteries. A unit rated for 6 liters of diesel has the current reserve to do that; a 1,000-amp compact unit does not, no matter what its peak number says.

If you drive a half-ton truck, a van, an older V8 or anything diesel, this is the size to buy and the extra weight is the cost of it working. If you drive a sedan or a small crossover, you are buying capability you will never call on.

Specs

  • 2,000 amp peak rating; NOCO rates it for gas up to 8 liters and diesel up to 6 liters
  • 4.18 lb (1.9 kg)
  • 56 watt-hour internal lithium-ion battery; up to 40 starts per charge per NOCO
  • 400-lumen LED work light with multiple modes
  • IP65 rated

Good for

  • Rated for diesel engines, which the GB40 is barely and most compact units are not at all
  • A 400-lumen light is bright enough to actually work under a hood by
  • Same reverse-polarity and spark-proof protection as the smaller NOCO units

Bad at

  • Nearly twice the weight and bulk of the GB40 -- this lives in a trunk, not a glovebox
  • Overkill and over-budget for a four-cylinder commuter car
  • Still charges relatively slowly for the battery size it carries
3

Best for a real display and fast recharging

HULKMAN Alpha 85

A 3.3-inch screen that tells you what is happening, 2,000 amps, and an hour to 80 percent. The best-informed jump start here.

Most jump starters communicate in blinking LEDs, which is fine until something is wrong and you are standing in a parking lot trying to decide whether the unit is flat, the clamps are backward or the battery is beyond help. A screen that names the error is worth more than a hundred amps of headroom.

The fast charging is the other genuine advantage. A 20,000 mAh pack on a slow micro-USB input is effectively an overnight job; 65 watts makes it a coffee break. If you plan to use the unit on multiple vehicles at a campsite or over a weekend, that changes how usable it is.

Specs

  • 2,000 amp peak rating; rated for up to 8.5 liters gas and 6.0 liters diesel
  • 20,000 mAh internal capacity; HULKMAN states up to 60 jump starts per charge
  • 3.3-inch screen showing operating status, charge level and error states
  • 65 W charging: 0 to 80 percent in about 1 hour, full in about 90 minutes per HULKMAN
  • IP65 rated shell; charge retention stated at up to 18 months

Good for

  • The screen removes the guesswork -- you see the state of charge and the error, not a blinking light
  • Recharges several times faster than the NOCO units, which matters after a weekend of use
  • The highest stated jumps-per-charge figure in this roundup

Bad at

  • A screen is one more thing to fail on a device that sits in a hot car for years
  • Larger and heavier than the GB40, so it is a trunk item
  • Shorter track record and a less-established warranty process than NOCO's
4

Best for small engines, motorcycles and a glovebox

NOCO Boost Sport GB20

500 amps and barely two pounds. The right size for a small car or a bike, and the wrong size for anything else.

This exists for a specific set of vehicles: motorcycles, powersports, small four-cylinder cars, and as a second unit for a household that already owns a bigger one. Within that set it is the right buy, because the weight and size are what determine whether it is actually in the vehicle.

Outside that set, do not stretch it. A 500-amp unit attempting a 3.5-liter V6 with a battery that has been flat for two days is a disappointment waiting in a parking lot, and the amount you saved over the GB40 is not worth that. Size up if you are between the two.

Specs

  • 500 amp peak rating; NOCO rates it for gas engines up to 4 liters
  • NOCO does not recommend it for diesel engines
  • 2.1 lb (0.95 kg) -- the lightest unit here
  • 24 watt-hour internal battery; up to 20 jump starts per charge per NOCO
  • 100-lumen LED light; IP65 rated

Good for

  • Light and small enough to live under a motorcycle seat or in a door pocket
  • Same spark-proof and reverse-polarity protection as the larger NOCO units
  • The cheapest route into a lithium jump starter from a brand with a real support record

Bad at

  • 500 amps is genuinely marginal -- a four-cylinder on a cold morning can defeat it
  • Not recommended for diesel at all
  • Smallest internal battery here, so fewer attempts before it needs charging
5

Best for the budget pick

GOOLOO GT1500

1,500 amps claimed, light, and a lot of capability for the money -- from a brand with less of a safety reputation behind it.

There is a legitimate budget case here and it rests on a boring fact: most jump starts are easy. A battery that went flat because a dome light stayed on overnight needs far less current than a cold cranking failure, and a competent cheap unit handles that all day.

What you give up is confidence in the numbers and confidence in the support. Read the claimed ratings on this one as the best case rather than the working case, and if you drive a diesel for a living, buy the NOCO. If you want a unit in the second car so nobody is stranded, this is a reasonable way to get one. For the standing-power side of a long trip, our portable power station roundup covers a different job entirely.

Specs

  • 1,500 amp peak claimed; GOOLOO states gas engines up to 8 liters and diesel up to 6 liters
  • 2.31 lb product weight
  • GOOLOO states up to 30 jump starts per charge and about 12 months of standby
  • USB outputs for charging phones; built-in LED light
  • Reverse-polarity and short-circuit protection claimed

Good for

  • Claimed engine ratings as high as units costing considerably more
  • Light for its claimed capability -- lighter than the GB40 despite higher claimed amps
  • Genuinely cheap enough to put one in a second car, which is the real-world argument

Bad at

  • The engine ratings and peak amp figure are the manufacturer's claims with no independent standard behind them
  • Support and warranty handling are less established than NOCO's, which is what you are paying NOCO for
  • Claimed specs in this price band are routinely optimistic -- treat 8 L gas as a ceiling, not a working rating

01 — Compare

The picks at a glance

Engine size rating is the spec to shop on. Peak amps is in the table because it is on every box, not because it is comparable between brands -- see the next section for why.

PickPeak ampsEngine ratingWeightBest for
NOCO Boost Plus GB401,000 A6 L gas / 3 L diesel2.4 lbMost cars
NOCO Boost Pro GB702,000 A8 L gas / 6 L diesel4.18 lbTrucks and diesels
HULKMAN Alpha 852,000 A8.5 L gas / 6 L dieselNot publishedDisplay and fast charging
NOCO Boost Sport GB20500 A4 L gas, no diesel2.1 lbMotorcycles, small engines
GOOLOO GT15001,500 A (claimed)8 L gas / 6 L diesel (claimed)2.31 lbBudget, second car

02 — Read the specs

Why peak amps is the wrong number to shop on

Walk down this category and you will see 1,000 amps, 2,000 amps, 4,000 amps and 6,000 amps, sometimes on units of near-identical size and battery capacity. The physics has not changed between them. The marketing has.

There is no enforced standard defining what a consumer jump starter's "peak amps" means. It is typically an instantaneous theoretical maximum, sometimes calculated rather than measured, and it says nothing about how long the unit can sustain current -- which is the part that actually cranks an engine. Two units with the same peak figure can behave completely differently, and a unit claiming six times the amps of another at the same weight and battery size is making a claim about arithmetic, not about capability.

The number that is harder to inflate, because it is a direct statement about what the product will do, is the engine size rating: "up to 6 liters gas, 3 liters diesel." That is a manufacturer committing to an application. Brands with a reputation to protect set those ratings conservatively. Brands without one set them optimistically, which is exactly why the two NOCO units in this list quote lower peak amps and lower engine ratings than cheaper units quoting more of both.

The second number worth reading is internal capacity in watt-hours or milliamp-hours, because that determines how many attempts you get. A jump start is rarely one clean crank. It is often three or four attempts separated by waiting, and a small battery runs out of those faster than its peak rating suggests.

  • Shop on engine size rating first. Match it to your largest vehicle, gas or diesel, and leave headroom for cold.
  • Treat peak amps as a brand signal, not a measurement. Unusually high claims at low weight and low capacity are the tell.
  • Check the diesel rating separately. Diesels crank against far higher compression; a gas rating tells you nothing about them.
  • Look for a stated operating temperature range. Lithium cells lose output in cold, which is the exact condition you bought the thing for.

03 — Safety

Safety: the feature that justifies the purchase

The reason to own a lithium jump starter instead of a set of jumper cables is not convenience, although it is more convenient. It is that it removes the two ways people get hurt or expensive.

The first is reverse polarity. Connecting positive to negative sends current the wrong way through a vehicle's electrical system, and in a modern car that can take out the alternator, the battery management system or the ECU. Every unit in this list claims reverse-polarity protection, and the NOCO units specifically will not deliver any current until the clamps are correctly placed. There is no equivalent protection on a pair of copper cables and a stranger's running engine.

The second is sparking near a battery. Lead-acid batteries vent hydrogen, and hydrogen plus a spark at the terminal is the mechanism behind the battery explosions that occasionally injure people. Spark-proof clamp design exists specifically to prevent that, and it is worth more than any amp figure on the box.

What a jump starter cannot do is fix a battery that has failed. If a battery has an internal short, a dead cell, or has sat deeply discharged long enough to sulfate, a jump start either will not work or will work once and leave you in the same position tomorrow. A jump starter buys you a trip to a shop; it does not replace one.

How many times can I attempt a jump?

Follow the manufacturer's instruction, which is typically to wait between attempts rather than crank repeatedly. Most units specify a cool-down between tries, and ignoring it both drains the pack and heats it. If three or four correctly connected attempts do not start the engine, the problem is not the jump starter.

Will a jump starter work in freezing weather?

Less well than in a warm garage, which is the inconvenient truth about lithium cells. Output drops as temperature falls, and the same cold morning that flattened your car battery is working against the jump starter too. Check the stated operating range, and keep the unit inside the cabin rather than the trunk in deep winter.

Can I leave it in the car all year?

Yes, with two caveats. Charge retention is finite -- manufacturers here quote 12 to 18 months -- so a unit left for three years will be flat when you need it. And repeated summer heat cycles in a trunk shorten lithium cell life. Set a reminder to top it up twice a year.

Is a jump starter the same as a power station?

No, and they are not substitutes. A jump starter delivers a huge current for a few seconds at 12 volts. A power station delivers a modest current for hours, usually at household voltage. See best portable power stations for that job.

04 — Practical

How to use one without damaging anything

Read your unit's instructions, because clamp order and boost-mode behavior differ between models. The general shape of the job is consistent, though, and knowing it in advance is the difference between a two-minute fix and a bad decision in a dark parking lot.

  • Turn the vehicle's ignition and all accessories off before connecting anything.
  • Connect the red clamp to the battery's positive terminal and the black clamp to the negative terminal or an unpainted engine ground, as your unit's manual specifies.
  • Confirm the unit shows a correct-connection state before powering it on. Do not override a warning indicator -- that indicator is the feature you paid for.
  • Crank the engine for a few seconds at most, then wait the interval the manual specifies before trying again.
  • Once running, disconnect the clamps in reverse order and let the vehicle run long enough to put charge back into the battery -- a short drive, not thirty seconds in the driveway.
  • Recharge the jump starter the same day. A unit put back in the trunk at 20 percent is a unit that fails next time.

05 — Honest limits

What we did not test, and what that means

We have not measured cranking current, sustained output, cold-weather performance or jumps-per-charge on these five units. Doing that properly needs a load bank, a temperature-controlled space and a lot of discharged batteries, and we have none of it. So there are no measured amp figures, no cold-crank results and no star ratings from us on this page.

Every figure here -- peak amps, engine size ratings, weights, capacities, jumps per charge, charge times, IP ratings and operating temperatures -- is the manufacturer's published specification, and where a number is a claim we have labeled it as one. That labeling is the point of this page rather than a disclaimer on it: the GOOLOO's 1,500 amps and the NOCO's 1,000 amps are not measurements taken the same way, and presenting them as a like-for-like comparison would be the dishonest thing to do.

The argument that peak amps is not a comparable specification is ours, and it follows from there being no enforced consumer standard defining it. We publish no prices -- this category is discounted constantly. Every buy link opens a live Amazon search for the model named. Full method at how we pick.

Questions

Frequently asked

What is the best portable jump starter?
The NOCO Boost Plus GB40 for most drivers: 1,000 amps, rated for gas engines up to 6 liters, 2.4 pounds, and it will not pass current if the clamps are reversed. Step up to the GB70 for a truck, a van or any diesel.
How many amps do I need in a jump starter?
Amps are the wrong spec to shop on -- there is no enforced standard for consumer peak amp claims. Use the engine size rating instead: match it to your largest vehicle, and check that the diesel rating is stated separately if you drive one.
Can a jump starter damage my car?
A reversed connection can damage an alternator, battery management system or ECU. That is exactly what reverse-polarity protection prevents, and it is the main reason a lithium jump starter is safer than cables. Never override a warning indicator.
Will a jump starter work on a diesel?
Only if it is rated for diesel. Diesels crank against much higher compression and often run two batteries, so a gas rating tells you nothing. The NOCO GB70 is rated to 6 liters diesel; the GB20 is not recommended for diesel at all.
How often should I charge a jump starter?
Twice a year is a reasonable habit. Manufacturers here quote 12 to 18 months of charge retention, and a unit that has sat in a trunk for three summers will be flat when you need it. Recharge immediately after any use.
Do jump starters work in cold weather?
Yes, but with reduced output -- lithium cells lose capability as temperature drops, on the same morning the cold flattened your car battery. Check the stated operating range and keep the unit in the cabin rather than the trunk in deep winter.
Is a jump starter better than jumper cables?
For most people, yes, because it does not require a second vehicle or a stranger, and it has reverse-polarity and spark protection that cables do not. Cables are lighter, cheaper and never go flat, which is a real argument for keeping both.

References

Back up a level

This page sits in Road Trip -- car camping and long drives: sleep, power, mounts, snacks.

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