We compared lithium jump starters on three things in this order: the gas and diesel engine sizes the maker actually rates them for, the safety of the clamps and protection circuitry, and whether the brand publishes a UL 2743 or CE statement.
Ad disclosure: we earn a commission on Amazon links, at no cost to you. It never decides our picks. How this works
Best overall
Suits Gas cars and small SUVs up to 6.0 L
Best budget
Suits Trucks, vans and big diesels on a budget
Best premium
Suits Full-size trucks, boats and diesels to 6.0 L
Best for trucks and SUVs
Suits Pickups and SUVs; wants a screen and fast recharge
From spec sheets and independent tests. The best result in a row is tagged.
| Feature | NOCO GB40Best overall | GOOLOO GT4000SBest budget | NOCO GB70Best premium | HULKMAN Alpha85Best for trucks and SUVs |
|---|---|---|---|---|
| Gas engine ratingmanufacturer | Up to 6.0 L | Up to 12.0 L Best | Up to 8.0 L | Up to 8.5 L |
| Diesel engine ratingmanufacturer | Up to 3.0 L | Up to 10.0 L Best | Up to 6.0 L | Up to 6.0 L |
| Peak currentmanufacturer, no common standard | 1,000 A | 4,000 A | 2,000 A | 2,000 A |
| Batterymanufacturer Wh and starts per charge | 24 Wh, up to 20 starts | 74 Wh, 60 starts Best | 56 Wh, up to 40 starts | 74 Wh, up to 60 starts Best |
| Safety standardpublished by brand or retailers | Partly: No UL 2743; CE per retailers | Partly: UL 2743 in earlier manual; CE, FCC listed | Partly: No UL 2743; CE per retailers | Yes: UL statement from Hulkman |
| Weather sealing | Yes: IP65, ports closed | Yes: IP65 | Yes: IP65, ports closed | Yes: IP65 |
| Recharge timemanufacturer | About 3 hr at 2 A | About 1.2 hr at 100 W Best | 6 to 8 hr over USB | About 90 min at 65 W |
| 12 V accessory output | No: USB only | Yes: 15 V 10 A DC, 150 W max | Yes: 12 V XGC port, 15 A | Yes: 15 V 10 A DC, 150 W max |
| Weightmanufacturer | 2.4 lb with clamps Best | Not published | 4.18 lb | 2.57 lb |
| On Amazon | Check price on Amazon(paid link) for NOCO Boost Plus GB40 1000A UltraSafe Lithium Jump Starter (opens in a new tab) | Check price on Amazon(paid link) for GOOLOO GT4000S 4000A SuperSafe Jump Starter (opens in a new tab) | Check price on Amazon(paid link) for NOCO Boost HD GB70 2000A UltraSafe Lithium Jump Starter (opens in a new tab) | Check price on Amazon(paid link) for HULKMAN Alpha85 2000A Smart Jump Starter (opens in a new tab) |
Who each one is for, and what to know before you buy.
01Best overall
The right jump starter for most drivers of four- and six-cylinder cars: small enough to live in the glovebox, safe enough to hand to someone who has never used clamps, and backed by a long record in independent tests.
Pick it ifOwners of gas cars and small SUVs up to 6.0 L who want a compact, mistake-proof pack that stays in the car
Skip it ifFull-size trucks, diesels over 3.0 L, or anyone who wants the pack to double as a serious USB power bank
Why it made the list. 1,000 A for gas engines to 6.0 L and diesels to 3.0 L in a 2.4 lb IP65 pack whose clamps TechGearLab rated the easiest and most secure in its group.
02Best budget
The budget pick for truck, van and diesel owners who want the highest engine rating on our list in a splash-resistant pack that recharges in just over an hour. Accept a bulky case and specs that vary between manual editions.
Pick it ifOwners of pickups, vans, RVs and big diesels who want a splash-resistant pack that recharges quickly and doubles as a laptop charger
Skip it ifDrivers of small cars who want the smallest glovebox pack, or buyers who need a published weight and a UL 2743 line in the current manual
Why it made the list. Rated for 12.0 L gas and 10.0 L diesel engines, the highest here, with an IP65 housing, a 3.2 in status screen and a 100 W USB-C input that refills it in about 1.2 hours.
03Best premium
The premium pick for V8 trucks, larger SUVs and diesels up to 6.0 L: NOCO's protection and clamps scaled up, with a 12 V accessory port and a housing built for a truck bed. Heavy and slow to recharge over USB.
Pick it ifOwners of full-size trucks, big SUVs, boats and diesels up to 6.0 L who want NOCO's safety design with real headroom
Skip it ifDrivers of small cars who will never use the rating, or anyone who wants a light pack that recharges in an hour
Why it made the list. 2,000 A for 8.0 L gas and 6.0 L diesel engines in a sealed IP65 housing with a 12 V accessory port, a manual override and a 400-lumen light.
04Best for trucks and SUVs
The pick for truck and SUV owners who want a pack that tells them exactly what it is doing: a large screen, truck-class engine ratings, a 90-minute recharge and an IP65 housing at 2.6 lb. The short cables and the lack of a NOCO-length track record are the trade-offs.
Pick it ifPickup, SUV and light-diesel owners who want a clear status display, fast USB-C recharging and a manufacturer UL statement
Skip it ifAnyone whose battery sits deep in the engine bay (the leads are short), or who needs a pack for sub-zero mornings without the pre-heat of the Alpha85S
Why it made the list. 2,000 A for 8.5 L gas and 6.0 L diesel, a 3.3 in status screen, a 65 W recharge in about 90 minutes, and a manufacturer UL statement, at 2.6 lb.
A jump starter is a lithium battery, a set of clamps and a protection circuit. The four packs here are all competent at the basic job; the differences are in how much engine they are rated for, how hard they are to misuse, and what the maker is willing to put in writing. Here is how we weighed each factor.
The most useful line on any spec sheet is the engine rating: "gas up to 6.0 L, diesel up to 3.0 L" for the NOCO Boost Plus GB40, "gas up to 8.5 L, diesel up to 6.0 L" for the HULKMAN Alpha85, and so on. Peak-amp claims are not measured to a common standard, which is why TechGearLab tells readers to compare engine ratings rather than headline amps. A 4,000 A label on one pack and a 1,000 A label on another do not mean the first is four times as strong.
Diesels matter twice. They need more cranking current for a given displacement, so every maker rates diesel capacity at roughly half the gas figure. If you own a 3.0 L diesel SUV, the GB40 is at its limit while the GOOLOO GT4000S and the NOCO Boost HD GB70 have margin to spare. Buy for the largest engine you might need to start, including a friend's truck in a parking lot.
A rough guide from the ratings on this list:
| Your largest engine | Pack |
|---|---|
| Gas up to 6.0 L or diesel up to 3.0 L | NOCO GB40 |
| Gas up to 8.0 L or diesel up to 6.0 L | NOCO GB70 |
| Gas up to 8.5 L or diesel up to 6.0 L | HULKMAN Alpha85 |
| Gas up to 12.0 L or diesel up to 10.0 L | GOOLOO GT4000S |
Every pack on this list refuses to pass current until it detects a battery connected the right way round. Reverse the clamps and you get a red light or a beeper rather than a spark; touch the clamps together and nothing happens. NOCO calls this UltraSafe, Gooloo calls it SuperSafe, Hulkman lists it among ten protection layers. It is the single feature that makes a lithium pack safe to hand to a teenager.
Clamp design is the second half. TechGearLab's testers put NOCO's thin-jaw clamps at the top of their group because they reach the recessed terminals on modern cars and grip firmly. Hulkman's clamps are adequate; we found no independent verdict on the GT4000S clamps. Short leads are a common complaint, so the pack often sits on the battery.
Both NOCOs and the Gooloo have a manual override or Boost mode that forces output when the vehicle battery is too flat for the pack to detect. That is essential on a deeply discharged battery, but it also disables the polarity check, so it belongs to whoever has read the guide.
The standard that covers lithium jump packs in the United States is UL 2743, and a manufacturer that cites it is telling you the pack has been assessed for the failure modes that matter: short circuits, over-charging, and thermal runaway. An earlier GOOLOO GT4000S manual prints "conforms to UL STD.2743"; the current edition's text lacks that line, and the amazon.com listing names CE and FCC. Hulkman's support center states that all of its products are UL certified to the standard for portable power packs. NOCO does not publish a UL 2743 line for the GB40 or GB70; retailers list its packs with CE, FCC, RoHS and UN 38.3 compliance, and NOCO's protection circuitry has more years of independent testing behind it than any competitor's. We accepted both routes and rejected packs that offered neither.
Watt-hours, not milliamp-hours, tell you how much energy a pack holds. The GB40 has 24 Wh, the GB70 56 Wh, and the Alpha85 and GT4000S 74 Wh each (current GT4000S manual; an earlier edition lists 99.2 Wh). Bigger is better for repeated starts and for using the pack as a power bank, but TechGearLab's measurements show that usable capacity runs well below the label on some packs: about two-thirds of the claim on the GB40, and under 60 percent on one no-name 4,000 A brick they tested. Manufacturers' "starts per charge" figures (20 for the GB40, 40 for the GB70, 60 for the other two) assume small engines and a warm day.
All lithium packs self-discharge, and every manual on this list says to top up every three months. Recharge speed matters when you discover the pack is flat on the morning you need it. The GT4000S is quickest, at about 1.2 hours on 100 W USB-C (a 100 W car charger is in the box), then the Alpha85 at about 90 minutes on 65 W; both makers say five minutes buys one start. The GB40 needs about 3 hours from a 2 A source, and the GB70 6 to 8 hours over USB. NOCO's 12 V fast charger cuts the GB70 to about 3 hours, but it is a separate purchase on current stock.
Published weights run from 2.4 lb with clamps (GB40) to 4.18 lb (GB70, about 5 lb with clamps per reviewers). Gooloo publishes none for the GT4000S; Outdoor Life lists its size as a con. All four have an IP65 housing. Extras worth having are a bright light with an SOS mode (the GB70 and GT4000S both list 400 lumens), a 12 V output for a tire inflator (GB70, GT4000S, Alpha85), and a screen that shows charge as a number (Alpha85 and GT4000S). If you also want camping or blackout power, pair a small pack with a unit from our best portable power stations list rather than buying a jump starter for its power-bank function.
Models we considered, and why each one did not make the list.
TechGearLab measured about 42 Wh of usable capacity from the ET03's claimed 74 Wh, and neither it nor the dozens of look-alike 4,000 A bricks on Amazon publish a UL 2743 or CE statement. A big peak-amp number with no engine rating and no standard is exactly what this list was designed to exclude.
TechGearLab's award for big engines and a strong pack, rated for 10.0 L gas engines, but it is heavier and bulkier than anyone with a passenger vehicle needs. The GB70 and Alpha85 cover the same trucks.
Our previous budget pick. Gooloo still sells it, but current US roundups (TechGearLab's April 2026 test, CNN Underscored) leave it out, and the GT4000S adds IP65 sealing and a far faster recharge.
TechGearLab's value pick, rated for 8.0 L gas and 6.0 L diesel with a 37 Wh battery. TechGearLab found it struggles on bigger engines, and no second current roundup backs it.
A lead-acid shop booster weighing around 18 lb. Reliable, but it is a garage tool, not something to carry in a car.
Nearly identical to the Alpha85 with a battery pre-heat that extends the working range to -40°F. If you live where that matters, buy it instead of the Alpha85; we listed the base model because it is the one most buyers in the lower 48 need.
TechGearLab's current top overall score, with strong measured efficiency. It is a newer brand with little long-term owner history yet, and we prefer to wait a year before recommending a safety product from it.
Not if it has reverse-polarity protection and you follow the connection order in the manual. Every pack on this list blocks output until the clamps are on the right terminals. The risk comes from manual override or Boost modes, which bypass that check; use them only when the pack cannot detect the battery and you are certain the clamps are right.
Only if your engine rating requires it. Most four- and six-cylinder gas engines need a few hundred cranking amps, which is why a 1,000 A pack like the GB40 handles them with room to spare. Match the manufacturer's engine rating to your largest engine and ignore the amp number on the box.
Manufacturers claim 12 to 24 months of standby, but every manual says to recharge every three months, and owner reports show packs left in hot cars lose capacity faster. Put a reminder in your calendar and store the pack out of direct sun.
All four are 12 V only; a 24 V system needs a different product. Boats and other 12 V lead-acid systems are fine. All four have IP65 housings, which resist spray but are not rated for immersion.
A modest one. The GT4000S and Alpha85 have enough capacity and 12 V outputs to run an inflator or charge a laptop; the GB40 is good for a couple of phone charges. For anything more, see our portable power stations list and keep the jump starter for its real job.
We compared lithium jump starters on three things in this order: the gas and diesel engine sizes the maker actually rates them for, the safety of the clamps and protection circuitry, and whether the brand publishes a UL 2743 or CE statement. For most cars the NOCO Boost Plus GB40 is the answer; trucks and diesels need the GOOLOO GT4000S, NOCO GB70 or HULKMAN Alpha85.
This is a research-based list; we have not used these packs ourselves. We built the shortlist from lab results at TechGearLab, roundups at CNN Underscored and Outdoor Life, reviews at How-To Geek, AutoGuide and CarXplorer, manufacturer spec sheets and manuals, and long-term owner reports. We required a manufacturer engine-size rating for both gas and diesel, spark-proof clamps with reverse-polarity protection, and a published safety-standard statement (UL 2743, UL for portable power packs, or CE compliance) from the brand, its manual or its retailers. Unbranded lithium bricks with only a peak-amp number were excluded, as were lead-acid boosters.
