How we researched this guide
We compared twelve portable jump starters sold for cars, trucks and shops, then ranked six that cover the field honestly: compact lithium, fast-charge lithium, a cold-weather lithium unit, two high-output lithium units and one lead-acid shop box. For every pick we read the maker spec sheet or manual and the Amazon item details, and checked the ASIN on the listing itself.
Owner evidence came from six sources — IH8MUD, Bogleheads, the JL Wrangler Forums, AR15.com, TractorByNet and Yesterdays Tractors — paraphrased and linked in each block, including the negative reports. We do not test jump starters. Engine ratings in this guide are maker ratings, written as rated to. The category home is our portable jump starters section, and head-to-heads live in jump starter comparisons.
The 30-second answer
Most drivers should buy the NOCO Boost Plus GB40: rated to 6.0L gas and 3.0L diesel at 2.4 lb. Want fast USB-C charging? The NOCO Boost X GBX45. Cold winters and a display? The Hulkman Alpha 85S. Big gas or diesel engines? The NOCO Boost Pro GB150. Past even that on maker ratings? The GOOLOO GT4000S. Starting vehicles all day in a shop? The lead-acid Clore Jump-N-Carry JNC660 — reserve over portability.
Best Overall for Most Cars
NOCO Boost Plus GB40
The compact benchmark: 1,000A, rated to 6.0L gas and 3.0L diesel, at 2.4 lb with spark-proof, reverse-polarity protection. Best if one car or SUV is the job and the pack will live in a glovebox.
Fastest Recharge
NOCO Boost X GBX45
The USB-C pick: 1,250A, rated to 6.5L gas and 4.0L diesel, with 60W Power Delivery in and out and a maker-stated 48-minute full recharge. Best if a flat pack is as bad as a flat battery.
Best for Cold Weather
Hulkman Alpha 85S
The winter pick: 2,000A, rated to 8.5L gas and 6.0L diesel, pre-heat technology, a -40F working-temperature rating and a 3.3-inch display. Best if starts happen in real cold.
Best Lithium for Big Engines
NOCO Boost Pro GB150
The heavy lithium pick: 3,000A, rated to 9.0L gas and 7.0L diesel, an 88Wh pack and up to 80 starts per charge on maker figures. Best if trucks, diesels and equipment share one pack.
Strongest Litre Ratings
GOOLOO GT4000S
The output pick: 4,000A peak, rated to 12.0L gas and 10.0L diesel, 100W two-way USB-C and a status screen. Best if your engine is past every other lithium rating here.
Best Lead-Acid Shop Box
Clore Jump-N-Carry JNC660
The reserve pick: a 22Ah lead-acid AGM box with 1,700 peak amps, long #2 AWG cables and a built-in automatic charger. Best if you start many vehicles, often, and weight does not matter.
| Jump starter | Peak amps | Maker engine rating | Recharge / output | Warranty | Check Price |
|---|---|---|---|---|---|
| NOCO Boost Plus GB40 | 1,000A | 6.0L gas / 3.0L diesel | Micro-USB in; USB out 5V/2.1A | 1 year | |
| NOCO Boost X GBX45 | 1,250A | 6.5L gas / 4.0L diesel | 60W USB-C PD in/out | 1 year | |
| Hulkman Alpha 85S | 2,000A | 8.5L gas / 6.0L diesel | 65W speed charge in; USB-C PD18W out | 2 years (maker-stated) | |
| NOCO Boost Pro GB150 | 3,000A | 9.0L gas / 7.0L diesel | XGC 12V in; USB out 5V/2.1A | 1 year | |
| GOOLOO GT4000S | 4,000A | 12.0L gas / 10.0L diesel | 100W USB-C PD in/out | 18 months | |
| Clore Jump-N-Carry JNC660 | 1,700A (425 cranking) | All vehicles, light commercial (no litre rating published) | Built-in automatic AC charger | 1 year |
Jump starter size calculator
Choose your fuel and enter your engine size in litres. We match it only against the maker litre ratings of the six picks in this guide — never against peak amps alone — and recommend the smallest pick whose rating covers your engine.
Not sure of your engine size? The vehicle table below lists typical engines by class. If your battery keeps dying rather than failing once, read why batteries drain and our battery guide — a jump pack treats the symptom, not a parasitic draw.
How to choose a portable jump starter
Start with the calculator above, not with the biggest amp number on a box. Peak amps are measured differently by every brand and are the least comparable figure in this market. The maker litre rating, the pack capacity behind it, how fast the pack refills, and how the unit behaves in cold weather decide whether a jump starter works on the morning you actually need it.
Peak amps vs engine size
Peak amps describe a brief maximum, not sustained cranking, which is why two 2,000A-class units can carry different engine ratings. Buy by the maker litre rating for your fuel, with headroom if your engine is old, cold or hard-starting. The GOOLOO also publishes a starting-current figure — 800A for three seconds — which is the more honest kind of number, and the Clore publishes 425 cranking amps alongside its 1,700 peak.
Gas vs diesel ratings — always the lower number rules
Diesel engines crank harder: higher compression and, on many trucks, glow plugs drawing current before the starter turns. Every lithium pick here therefore carries a diesel rating well below its gas rating — the GB40 drops from 6.0L gas to 3.0L diesel. If you drive a diesel, ignore the gas headline completely and size only from the diesel column of the spec table.
Lithium vs lead-acid — portability vs reserve
Lithium packs are light, hold charge well in storage and add USB power, but their total energy is small — tens of watt-hours. The lead-acid JNC660 carries a 22Ah battery, far more reserve for repeated starts and for powering vehicle electronics while you work, at 18 lb and with a battery that eventually needs replacing. Choose lithium for a vehicle, lead-acid for a workplace.
Recharging speed and USB-C PD
A jump pack that takes all night to refill gets left flat. The GBX45 refills in a maker-stated 48 minutes on 60W USB-C PD and the GT4000S in about 1.2 hours on 100W, while the GB40 still uses Micro-USB and the GB150 is slow on USB — its 12V XGC input is the faster route. USB-C PD output also matters if the pack doubles as laptop power; PD18W, on the Hulkman, will not do that job like 60W or 100W will.
Safety protections — reverse polarity and spark-proof
The protection that matters most is the one that forgives a tired, dark, rushed connection: reverse-polarity detection and spark-proof clamps. All three NOCO picks and the Hulkman publish those protections, and the GOOLOO publishes a protection list including overcharge, overload and short-circuit. Manual override modes exist for batteries too flat to be detected — useful, and the one mode where those protections are deliberately bypassed, so it is never a first step.
Cold-weather performance and storage
Cold cuts lithium output at exactly the moment engines crank hardest. Operating ratings here run from -20C on the NOCO packs to a -40F working rating with pre-heat on the Hulkman 85S. Storage matters as much: keep any pack charged, check it on a schedule rather than after a failure, and never charge a lithium pack outside its published charging-temperature range. Our maintenance checklist habit — inspect on a calendar, not on a breakdown — applies here too.
Typical engine sizes by vehicle class
Typical factory engines, as sizing examples — check your own engine code before buying. The pick column is this guide applying the maker ratings above, the same logic as the calculator.
| Vehicle class | Typical engines | Sizing guidance | Pick that covers it |
|---|---|---|---|
| Compact and midsize cars | 1.5–2.5L gas | Small gas engines sit well inside the smallest rating here | NOCO GB40 |
| Full-size cars and crossovers | 2.0L turbo to 3.6L gas | Turbo fours and V6s are GB40 territory; USB-C buyers step up | NOCO GB40 / GBX45 |
| Half-ton pickups, gas | 5.3L, 5.7L and 6.2L V8 gas | Inside GBX45 and Hulkman gas ratings | Hulkman Alpha 85S |
| Half-ton pickups, diesel | 3.0L diesel | Exactly at the GB40 diesel ceiling — buy headroom instead | NOCO GBX45 |
| Heavy-duty pickups, diesel | 6.6L and 6.7L diesel | Past the Hulkman diesel rating; inside GB150 at 7.0L | NOCO GB150 |
| Large diesels and equipment | Diesel above 7.0L, to 10.0L | Only the GOOLOO diesel rating reaches this band | GOOLOO GT4000S |
| Shops and fleets, mixed | Mixed gas and diesel, many starts a day | Reserve and cable reach beat litre ratings | Clore JNC660 |
Truck owners sizing other 12V gear will recognise the discipline: rate for the real load, not the badge — the same rule behind what size winch do I need and diesel truck winch picks.
Portable jump starters by budget tier
| Tier | What you get | Example pick |
|---|---|---|
| Entry tier | A compact lithium pack for one car, basic USB out, slower Micro-USB charging | NOCO GB40 |
| Mid tier, fast charge | More rating headroom plus 60W USB-C PD in and out and a sub-hour refill | NOCO GBX45 |
| Mid tier, cold and display | A smart display, pre-heat for extreme cold and 65W speed charging | Hulkman Alpha 85S |
| Upper tier, lithium | The biggest lithium energy here and ratings for large gas and diesel engines | NOCO GB150 |
| Upper tier, output | The strongest litre ratings, 100W two-way charging and a status screen | GOOLOO GT4000S |
| Shop tier | Lead-acid reserve, long heavy cables and a built-in charger — bought for duty, not travel | Clore JNC660 |
Types of portable jump starter
| Type | Pros | Cons | Best for |
|---|---|---|---|
| Compact lithium | Lightest and smallest; holds charge in a glovebox; doubles as a phone power bank | Smallest energy reserve; slowest charging on older models; diesel ratings are modest | One car or SUV — GB40, GBX45 |
| High-output lithium | Ratings for large V8s and diesels; fast USB-C PD; displays on some models | Bigger and heavier than compact packs; headline peak amps still not comparable across brands | Trucks, diesels, mixed households — Hulkman, GB150, GT4000S |
| Lead-acid jump box | Large reserve for repeated starts; long, heavy cables; simple, repairable battery | Heavy; battery needs periodic charging and eventual replacement; few modern ports | Shops, fleets, farms — JNC660 |
| Inflator-combo | One box jumps and inflates | No pick in this guide is a true inflator-combo: the GOOLOO and Clore DC outlets power a separate inflator instead, which keeps each tool replaceable | Drivers who value one-box storage over tool quality — not ranked here |
If portable power for other gear is part of the brief, compare the approach in portable winches, portable 12V winches and 12V picks for the money — different tools, same reserve-versus-weight trade.
Detailed reviews: the six picks in full
Each pick is checked the same way: why it earns its place, what the maker publishes, who it fits, what owners report — good and bad — and who should walk past it. Conflicts found in maker or listing figures are printed, not smoothed over.
Best Overall for Most Cars: NOCO Boost Plus GB40
Best Overall for Most Cars — the compact pack most drivers actually need
Why the NOCO GB40 is our pick
The GB40 wins on fit, not force. Most dead-battery mornings involve a mainstream gas engine, a battery that is flat rather than destroyed, and a driver who wants the pack back in the glovebox afterwards. A 1,000A pack rated to 6.0L gas, at 2.4 lb, with NOCO spark-proof and reverse-polarity protection, is exactly that shape — and its long production run means its weaknesses are known, not hidden.
NOCO GB40 key specs
- Part number: GB40
- Peak current: 1,000A
- Maker engine rating: Gas up to 6.0L; diesel up to 3.0L
- Starts per charge: Up to 20 (maker)
- Internal battery: Lithium-ion (Wh not published in the manual checked)
- Charging input: Micro-USB, 5V/2.1A
- USB output: 5V, 2.1A
- Safety: Spark-proof connections; reverse-polarity protection; manual override for very low batteries
- Housing: IP65 (ports closed)
- Operating temperature: -20C to +50C; charging 0C to +40C
- Light: 100-lumen LED, 7 modes
- Weight: 2.4 lb
- Warranty: 1-year limited
NOCO GB40: fits and best for
Cars, crossovers and SUVs with gas engines to 6.0L, small diesels to 3.0L, motorcycles and mowers. It is the glovebox pick for a single-vehicle household, a teen driver, or a second car — anywhere the job is occasional starts, not daily duty. Readers cross-shopping our portable truck gear will recognise it as the same philosophy: carry the rated tool, not the biggest one.
NOCO GB40 pros and watch-outs
Pros
- Small and light enough to live in the car permanently
- Spark-proof, reverse-polarity protection suits first-time users
- Manual override exists for batteries too flat to detect
- Long production run — behaviour and limits are well documented
- IP65 housing with ports closed
Watch-outs
- Micro-USB charging is slow and dated next to USB-C PD picks
- Diesel rating stops at 3.0L — most diesel trucks need a bigger pick
- Small pack energy: phone charging drains jump reserve quickly
- No display — four LEDs are the whole fuel gauge
NOCO GB40: what owners report
On Bogleheads, an owner reports using a GB40 over a dozen times without a failure, praising the sturdy clamps and the override that lets it deliver a jump when a battery shows almost no detectable voltage; several owners in the same discussion say they keep one in each family car.
Balance comes from IH8MUD, where an owner reports a GB40 failing to crank a totally flat large SUV and prefers a larger unit for overhead in adverse conditions. Both reports are consistent with the rating: inside 6.0L gas it is dependable; at the edge, buy headroom.
NOCO GB40: who should not buy
Diesel truck owners above 3.0L should not buy this pack — it is below the maker rating for your engine. Start instead with the NOCO GB150 or the GT4000S block below, and size from the diesel column only.
NOCO GB40: pair it with
Pair it with its own bigger sibling for a two-vehicle household: keep the GB40 in the car and the GBX45, with its 60W USB-C charging, in the vehicle that does longer trips.
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Tip: recharge the GB40 after every use and check it on a calendar reminder, not after a failure. Our guide to how long a battery carries a load explains why small packs feel empty sooner than expected.
Fastest Recharge: NOCO Boost X GBX45
Fastest Recharge — the USB-C pick for drivers who hate waiting on a pack
Why the NOCO GBX45 is our pick
The GBX45 fixes the GB40 generation complaint that matters most in real ownership: refill time. NOCO rates it at 1,250A for 6.5L gas and 4.0L diesel, adds 60W USB-C Power Delivery in both directions, and states a 48-minute full recharge — or enough charge for a jump after five minutes from flat. If a jump pack is only useful when it is ready, recharge speed is a starting feature, not a convenience.
NOCO GBX45 key specs
- Part number: GBX45
- Peak current: 1,250A
- Maker engine rating: Gas up to 6.5L; diesel up to 4.0L
- Starts per charge: Maker listings conflict: up to 6 (US) vs up to 8 (UK) — unresolved
- Internal battery: 31 Wh lithium-ion
- USB-C input/output: 60W Power Delivery, profiles to 20V/3A
- USB-A output: 5V, 2.1A, 10W max
- Safety: UltraSafe 2.0: spark-proof, reverse-polarity, enhanced thermal management; 60-second timer
- Housing: IP65 (ports closed)
- Recharge time: 48 minutes (maker, USB-C PD); jump-ready in 5 minutes
- Light: 100-lumen LED, 7 modes
- Weight: 1.30 lb unit; 2.16 lb with clamps
- Warranty: 1-year limited
NOCO GBX45: fits and best for
Gas cars and SUVs to 6.5L and diesels to 4.0L, especially in households that will actually keep a pack charged because it refills from the same USB-C PD charger as a laptop. It suits commuters, rideshare and delivery drivers, and anyone who wants one power bank that can also start the car — within the honest limit that jump reserve comes first.
NOCO GBX45 pros and watch-outs
Pros
- 60W USB-C PD in and out — the modern charging standard, both ways
- Maker-stated 48-minute full recharge; 5 minutes to a jump
- More diesel headroom than the GB40 (4.0L vs 3.0L)
- Very light even with clamps (2.16 lb)
- 60-second timer conserves pack energy between attempts
Watch-outs
- Starts-per-charge figures conflict between maker listings (6 vs 8)
- 1-year warranty, like the rest of the NOCO line here
- Small 31Wh pack — laptop charging and jump reserve compete
- No status display; LEDs only, unlike the Hulkman and GOOLOO
NOCO GBX45: what owners report
Dedicated long-term owner coverage of the GBX45 specifically is thinner than for the older GB40 — said plainly rather than borrowed from other Boost X models. The owner record that exists, on its Amazon listing, centres on the fast recharge and compact size, which matches the spec sheet: this is a convenience-led pick.
The cautionary theme from GB40 owners on IH8MUD applies to the whole compact class: a totally flat battery in a large vehicle is where small packs run out of overhead, whatever the badge. Size from the litre rating, not from hope.
NOCO GBX45: who should not buy
If your diesel is above 4.0L, this pack is below its maker rating for your engine — move to the Hulkman or GB150 below. If you want a screen that tells you pack state in plain language, the GBX45 LEDs will frustrate you; that is the Hulkman case.
NOCO GBX45: pair it with
Pair it with the GB40 as the household second pack: same NOCO protection logic and clamp style in both cars, so nobody has to learn two different units at the roadside.
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Tip: use a genuine 60W-class USB-C PD charger — a small phone brick will not deliver the 48-minute refill. Keep the PD brick with the pack, the way you would keep the right cable with electric truck gear.
Best for Cold Weather: Hulkman Alpha 85S
Best for Cold Weather — pre-heat, a real display, and ratings for large engines
Why the Hulkman Alpha 85S is our pick
The Alpha 85S is built around the two moments compact packs fail: deep cold and user uncertainty. Hulkman publishes a -40F working-temperature rating with automatic pre-heat, a 3.3-inch display that shows status and errors in plain form, and ratings of 8.5L gas and 6.0L diesel from a 74Wh pack. Its USB-C output is only PD18W — the display and the cold rating, not power-bank speed, are what you are buying.
Hulkman Alpha 85S key specs
- Part number: Alpha 85S
- Peak current: 2,000A
- Maker engine rating: Gas up to 8.5L; diesel up to 6.0L (official spec page; an Amazon summary printing 6.5L diesel conflicts)
- Starts per charge: Up to 60 (maker comparison table)
- Internal battery: Lithium-polymer, 74Wh / 20,000mAh at 3.7V
- USB-C input: 65W speed charge (SC) / PD18W
- USB-C output: PD18W
- USB-A output: QC3.0 18W
- DC output: 15V/10A, 150W max
- Operating temperature: -40F to 113F working (official spec page)
- Display / light: 3.3-inch smart display; 400-lumen LED, 5 modes
- Weight: 2.57 lb (product, official spec page; kit weights vary by listing)
- Warranty: 2 years, maker-stated
Hulkman Alpha 85S: fits and best for
Cold-climate cars, SUVs and trucks, gas to 8.5L and diesel to 6.0L — including half-ton diesels that are past the GBX45 rating. It fits drivers who want the unit to tell them what is wrong instead of blinking a code, and anyone whose vehicle sleeps outside in winter. The 15V DC outlet also runs tyre inflators and similar 12V gear, though it is not itself an inflator.
Hulkman Alpha 85S pros and watch-outs
Pros
- Pre-heat technology with a -40F working rating — the cold pick
- 3.3-inch display shows charge, status and errors clearly
- Strong diesel rating (6.0L) for a pack this size
- 65W speed charge: maker states about 1.5 hours to full
- 10 protection types published, including reverse polarity and spark-proof
Watch-outs
- The 65W wall charger is not included with the 85S — budget for it
- USB-C output is only PD18W, weak for laptops
- Maker and listing figures conflict in places (diesel rating, kit weight)
- Owner coverage is thinner than NOCO long-run models
Hulkman Alpha 85S: what owners report
Owner and review coverage collected for this model centres on three recurring points, summarised from its Amazon owner listing: the display makes first use calmer, pre-heat is the reason cold-climate buyers chose it, and the missing wall charger is the recurring annoyance.
Hulkman own user-guide material, reproduced at ManualsPlus, shows the force-start mode and its warning that auto-detection and safety features are disabled in that mode — worth knowing before you need it, and a reason the display matters.
Hulkman Alpha 85S: who should not buy
If you mainly want a fast laptop power bank, PD18W output is the wrong tool — the GBX45 or GT4000S charge devices far faster. If your diesel is above 6.0L, this pack is below rating; the GB150 and GT4000S blocks are yours.
Hulkman Alpha 85S: pair it with
Pair it with the compact GB40 for a second, warmer-climate vehicle: the Hulkman covers the truck in winter, the NOCO covers the car all year.
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Tip: let pre-heat finish — the display shows READY when the pack has warmed itself. Forcing repeated cranks in deep cold wastes the reserve the pre-heat is protecting, the same patience rule as using powered recovery gear properly.
Best Lithium for Big Engines: NOCO Boost Pro GB150
Best Lithium for Big Engines — the lithium pack for large gas, diesel and equipment
Why the NOCO GB150 is our pick
The GB150 is the point where a lithium pack stops being an emergency gadget and becomes truck equipment: 3,000A, maker ratings of 9.0L gas and 7.0L diesel, an 88Wh internal battery and up to 80 starts per charge on maker figures. It is also the NOCO for diesels the smaller packs honestly cannot cover — heavy-duty 6.6L and 6.7L diesels sit inside its 7.0L diesel rating and outside everyone elses except the GOOLOO.
NOCO GB150 key specs
- Part number: GB150
- Peak current: 3,000A
- Maker engine rating: Gas up to 9.0L; diesel up to 7.0L
- Starts per charge: Up to 80 (maker)
- Internal battery: 88 Wh lithium-ion
- Charging inputs: Micro-USB 5V/2.1A; XGC 12V/5A fast charge
- Outputs: USB 5V/2.1A; XGC 12V/15A power supply
- Safety: Spark-proof connections; reverse-polarity protection; manual override
- Housing: IP65 (ports closed)
- Operating temperature: -20C to +50C; charging 0C to +40C
- Light: 500-lumen LED, 7 modes
- Weight: 6 lb unit; 7.5 lb with clamps and accessories
- Warranty: 1-year limited
NOCO GB150: fits and best for
Full-size and heavy-duty trucks, large V8s, diesels to 7.0L including the common 6.6L and 6.7L heavy-duty diesels, tractors and equipment that share a yard with the truck. It fits owners who start more than one kind of machine and want one lithium pack with a voltmeter and a 12V supply output — at the cost of carrying 6 lb instead of 2.
NOCO GB150 pros and watch-outs
Pros
- Diesel rating (7.0L) covers heavy-duty pickups the smaller NOCOs cannot
- Largest NOCO energy here (88Wh) and up to 80 maker-stated starts
- Built-in voltmeter helps tell a flat battery from a dead one
- XGC 12V output runs accessories, not just phones
- 500-lumen light is genuinely work-grade
Watch-outs
- Slow to refill on USB — use the XGC 12V input where you can
- 6 lb is a truck pack, not a glovebox pack
- 1-year warranty on the most expensive-feeling NOCO here
- No USB-C at all — charging ecosystem is a generation behind
NOCO GB150: what owners report
On the JL Wrangler Forums, an owner reports a GB150 starting a JL with a dead auxiliary battery shortly after hook-up, after charging the pack overnight — the awkward dual-battery case that defeats many small packs.
An Amazon owner report reproduced by a retailer describes a cold-day start of a hard-starting diesel tractor after the pack had sat charged in a truck for over a month, holding full charge through freezing weeks; the same owner notes USB charging is slow — see the owner report reproduction.
NOCO GB150: who should not buy
Car-only drivers should not buy this pack — you are carrying triple the GB40 weight for ratings you will never use. And if your diesel is above 7.0L, even this is below rating: the GT4000S, rated to 10.0L diesel, is the honest next step.
NOCO GB150: pair it with
Pair it with the GB40 for the household car: GB150 stays with the truck and equipment, GB40 lives in the car, and neither vehicle borrows the others pack.
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Tip: charge it on the 12V XGC input in the truck rather than USB — the time difference is the difference between a pack that is ready and one that is not. Battery health context is in our winch battery guide.
Strongest Litre Ratings: GOOLOO GT4000S
Strongest Litre Ratings — the output pick for engines past the NOCO ratings
Why the GOOLOO GT4000S is our pick
The GT4000S exists in this guide for one honest reason: its maker ratings go where the others stop — 12.0L gas and 10.0L diesel, with 4,000A peak, a published 800A starting-current figure, 100W two-way USB-C and a 3.2-inch status screen. That reach comes with the messiest owner record in the guide, printed in full below. Buy it for rating coverage and charging speed, with your eyes open.
GOOLOO GT4000S key specs
- Part number: GT4000S
- Peak current: 4,000A; starting current 800A for 3s (maker)
- Maker engine rating: Gas up to 12.0L; diesel up to 10.0L
- Starts per charge: Up to 60 (maker listing)
- Internal battery: 20,000mAh lithium-polymer (Amazon item details; Wh figures conflict across listings — see owners note)
- USB-C input/output: 100W Power Delivery two-way; full charge about 1.2 hours (maker)
- Other outputs: USB QC3.0 18W; USB 5V/2.4A; DC 15V/10A, 150W max
- Safety: Protection list incl. overcharge, overload, short-circuit and reverse polarity (maker)
- Housing: IP65 (maker spec reproductions)
- Operating temperature: -20C to +60C (maker)
- Light / display: 400-lumen LED, 3 modes; 3.2-inch status screen
- Weight: About 4.9 lb (maker spec reproductions)
- Warranty: 18 months (Amazon manufacturer warranty description; some listings print 2 years)
GOOLOO GT4000S: fits and best for
Large gas engines, diesels between 7.0L and 10.0L, tractors, boats and mixed fleets kept by one household — anywhere the GB150 diesel ceiling is the problem. It also fits power users: 100W USB-C in and out makes it the only pick here that can refill itself fast and charge a laptop at full speed, and the DC outlet runs inflators and inverters within its 150W limit.
GOOLOO GT4000S pros and watch-outs
Pros
- Strongest maker litre ratings in the guide, gas and diesel
- 100W two-way USB-C — fastest refill and device charging here
- Published starting-current figure, not just a peak headline
- Status screen shows charge and mode at a glance
- DC outlet powers separate inflators and 12V gear
Watch-outs
- Mixed owner record — charging faults and error codes reported by some owners
- Capacity and warranty figures conflict across listings
- Clamps reported awkward on side-post batteries
- Peak-amp headline is not comparable with NOCO ratings
GOOLOO GT4000S: what owners report
On AR15.com, owners split sharply: several report GT-line units with charging problems, error codes and weaker-than-expected output even after a replacement, while others in the same thread report owning many units across cars and a work truck — used on diesels, tractors and loaders — without a failure. Both halves are printed because both are the record.
An Amazon owner report reproduced in a review roundup describes a fully charged GT4000S failing to crank a nearly dead 5.3L V8 that a smaller NOCO then started, and criticises the clamp covers on side-post terminals — see the summary at Smart Auto. Treat the litre ratings as coverage, not as a guarantee on a destroyed battery.
GOOLOO GT4000S: who should not buy
If reliability record matters more than rating reach, do not buy this pack — the GB150 covers diesels to 7.0L with a cleaner owner record. If your engine is inside NOCO ratings, the GOOLOO extra reach buys you nothing but the conflicts above.
GOOLOO GT4000S: pair it with
Pair it with the JNC660 in a workshop: the GOOLOO travels in the truck for its rating reach, the lead-acid box stays plugged in at base for repeated starts.
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Tip: on side-post batteries, seat the clamps deliberately and check the screen for a ready indication before cranking — the clamp fit is the documented weak point. General clamp discipline is in our accessories guide.
Best Lead-Acid Shop Box: Clore Jump-N-Carry JNC660
Best Lead-Acid Shop Box — reserve, cable reach and a built-in charger — the shop standard
Why the Clore JNC660 is our pick
The JNC660 is the anti-lithium pick, and shops keep buying it for reasons the spec sheet explains: a 22Ah lead-acid battery with far more reserve than any lithium pack here, 425 cranking amps behind the 1,700 peak figure, 46 inches of #2 AWG cable that actually reaches awkward batteries, and a built-in automatic charger so the box lives plugged in and ready. Clore publishes no litre rating — it rates the box for all vehicles and light commercial use — so we print that, not an invented number.
Clore JNC660 key specs
- Part number: JNC660
- Peak current: 1,700A; cranking amps 425
- Maker engine rating: All vehicles, light commercial (no litre rating published)
- Internal battery: 22Ah Clore Proformer lead-acid AGM
- Cables: 46 in, #2 AWG, heavy-duty clamps
- Charging: Built-in automatic charger; male-to-male 12V charging cable included
- Outputs: 12V DC outlet for accessories (no USB published)
- Charge indicator: Voltmeter showing onboard battery status
- Safety: Grip guards on clamps; no spark-proof electronic protection published — connect carefully
- Light: None built in
- Weight: 18 lb
- Warranty: 1-year limited
Clore JNC660: fits and best for
Workshops, farms, fleets, tow and lot work — anywhere starts are repeated, batteries are deeply flat, and the box returns to a wall socket afterwards. It also fits owners who keep vehicles, tractors and boats in one place and want one box that can start them in sequence, power 12V accessories while working, and have its internal battery replaced years later instead of scrapping the unit.
Clore JNC660 pros and watch-outs
Pros
- Reserve capacity dwarfs every lithium pack here (22Ah)
- Long, heavy #2 AWG cables reach real-world battery positions
- Built-in automatic charger — leave it plugged in, always ready
- Cranking amps published (425), not just a peak headline
- Internal battery is replaceable — the box is not disposable
Watch-outs
- 18 lb — it travels by handle, not in a glovebox
- No litre rating, USB ports, display or built-in light
- Lead-acid battery needs periodic charging and eventual replacement
- No published electronic spark-proof protection — technique matters
Clore JNC660: what owners report
On the JL Wrangler Forums, the JNC660 enters the discussion as the tow-truck class answer: a poster notes its 22Ah battery against a small lithium packs roughly 1.2Ah, and the original poster buys one alongside keeping the NOCO — reserve in the shop, lithium in the vehicle.
On TractorByNet, an owner reports twelve years from a JNC660 kept plugged in, starting a big diesel truck, calling the brand a dealer go-to for power and longevity; on Yesterdays Tractors, owners discuss replacing its internal battery rather than replacing the box. Weight is the constant complaint, and the constant trade.
Clore JNC660: who should not buy
If the pack must live in a car, travel in luggage, or be carried by someone who will not lift 18 lb to a battery, do not buy this box — any lithium pick here is the right shape. If you need USB-C device charging, the JNC660 simply does not offer it.
Clore JNC660: pair it with
Pair it with the GB40: the Clore stays plugged in at base for hard and repeated starts, the NOCO travels in the vehicle for the one-start emergency away from home.
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Tip: leave the JNC660 on its built-in charger and recharge it after every use — lead-acid life is decided by never sitting flat. The same storage discipline is behind protecting gear that lives ready and our maintenance checklist.
Spec comparison
All six picks side by side, on maker-published figures only. Where a maker publishes nothing, the cell says so — that silence is part of the comparison.
| Spec | GB40 | GBX45 | Hulkman 85S | GB150 | GT4000S | JNC660 |
|---|---|---|---|---|---|---|
| Peak current | 1,000A | 1,250A | 2,000A | 3,000A | 4,000A | 1,700A |
| Cranking / starting current | Not published | Not published | Not published | Not published | 800A for 3s (maker) | 425 cranking amps |
| Gas rating | 6.0L | 6.5L | 8.5L | 9.0L | 12.0L | No litre rating published |
| Diesel rating | 3.0L | 4.0L | 6.0L | 7.0L | 10.0L | No litre rating published |
| Internal battery | Lithium-ion, Wh not published | 31 Wh lithium-ion | 74Wh lithium-polymer | 88 Wh lithium-ion | 20,000mAh lithium-polymer | 22Ah lead-acid AGM |
| Starts per charge (maker) | Up to 20 | Up to 6–8 (listings conflict) | Up to 60 | Up to 80 | Up to 60 | Not published |
| Fastest recharge | Micro-USB (slow) | 60W USB-C PD, 48 min | 65W speed charge, about 1.5 h | XGC 12V input | 100W USB-C PD, about 1.2 h | Built-in AC charger |
| Device output | USB 5V/2.1A | USB-C 60W PD | USB-C PD18W | USB 5V/2.1A; XGC 12V/15A | USB-C 100W PD; DC 150W | 12V DC outlet |
| Operating temperature | -20C to +50C | Not published | -40F to 113F | -20C to +50C | -20C to +60C | Not published |
| Weight | 2.4 lb | 2.16 lb with clamps | 2.57 lb | 7.5 lb with clamps | About 4.9 lb | 18 lb |
| Warranty | 1 year | 1 year | 2 years (maker-stated) | 1 year | 18 months | 1 year |
| Check Price |
Using a jump starter: procedure and fitment notes
The procedure is the same for every pick here, and the makers agree on the order. Park both vehicles — or the pack — close, switch everything off, and identify the battery terminals before any clamp moves. Connect the red clamp to the positive terminal, then the black clamp to a solid unpainted metal ground on the engine or chassis, away from the battery — not, on most maker instructions, straight to the negative terminal. Power the pack on, wait for its ready indication, then crank in short attempts. Once the engine runs, switch the pack off and remove the clamps in reverse order, ground first. Our background reading on 12V systems — how many amps a 12V load draws and budget truck electrics — explains why cable and connection quality decide these moments.
Fitment notes that actually bite: side-post GM batteries give shallow clamps a poor grip — the documented GT4000S complaint — so seat clamps deliberately; dual-battery diesels and Jeeps with an auxiliary battery can need the pack left connected briefly before cranking, as the GB150 owner report shows; and a hybrid or EV 12V battery is jump-started at its published jump points only, never at the traction battery. If a vehicle needs jumping repeatedly, the fault is the vehicle battery or charging system, not the pack — see why vehicle batteries drain.
Safety essentials
Six rules that outrank every pick in this guide:
- Connect red to positive first and black to a ground away from the battery; remove them in reverse order.
- Never use manual override or force-start as a first step — it disables the protections that make these packs safe.
- Keep sparks, flames and smoking away from a battery being jumped; batteries vent hydrogen, especially after deep discharge.
- Stop and reassess after a few short crank attempts — repeated cranking overheats starters, clamps and packs.
- Never charge a lithium pack below freezing or leave any pack in a hot closed vehicle beyond its storage rating.
- A swollen, cracked, hot or leaking pack is finished — do not charge it, jump with it, or store it indoors near exits.
NOCO GB40 as the household backup — a second, smaller pack means the main pack is never borrowed and missing. See the full field in portable jump starters.
GOOLOO GT4000S for DC accessories — its 150W DC outlet powers a separate tyre inflator, so a flat tyre and a flat battery can both be handled without a built-in combo tool.
Clore JNC660 for the workshop — the plugged-in reserve box for repeated starts and for powering 12V gear while you diagnose. The wider kit list is in essential accessories and recovery kit picks.
Troubleshooting
| Symptom | Likely cause | Fix |
|---|---|---|
| Clicks but no crank | Weak connection, a battery too flat to detect, or a pack below its rating for that engine | Reseat clamps on clean metal, check the pack charge, leave it connected a minute, then try the maker override only as directed — and if the engine is above the pack rating, use a bigger pick |
| Pack will not switch on or take charge | Pack deeply discharged in storage, a failed cable, or charging outside its temperature range | Bring it indoors to room temperature, try the maker cable and a known-good charger of the right wattage, and leave it connected — deeply flat packs can take time to wake |
| Error light or screen code at connection | Reverse polarity, shorted clamps, or a vehicle battery fault | Remove both clamps, check terminal markings in daylight, reconnect in the correct order; a repeated error on a correct connection points at the vehicle battery |
| Starts once, then nothing on the second attempt | Pack reserve spent — phone charging, repeated cranks, or cold-soaked lithium | Recharge the pack fully before judging it; in cold, warm a lithium pack indoors or use a pre-heat model, and charge the vehicle battery properly between attempts |
| Swollen or hot battery pack | Internal cell damage or age — a safety fault, not a performance fault | Stop using and charging it immediately, move it away from flammables outdoors if safe to do so, and follow local battery-disposal rules; never puncture or open it |
| Vehicle starts, then dies when the pack is removed | The vehicle battery cannot hold charge or the alternator is not charging | The jump pack did its job — the vehicle needs a battery or charging-system repair, not a bigger pack; get the battery load-checked |
Who should NOT buy these
Your diesel is above 10.0L, or your system is 24V. Nothing in this guide is rated for you — every pick here is a 12V unit, and the strongest diesel rating stops at 10.0L. Heavy commercial and semi applications need dedicated heavy-duty equipment, not a bigger guess from this page.
Your battery is failing, not flat. A jump starter revives a discharged battery for a trip; it does not repair a sulphated, shorted or frozen one. If the same vehicle needs jumps weekly, spend on the vehicle battery and charging system first — background in battery sizing and health.
You will not maintain a pack. Every unit here, lithium or lead-acid, self-discharges in storage. If nobody will check and recharge it on a schedule, it will be flat on the day it is needed, whatever its badge says.
You need an inflator, compressor and jump pack in one box. No pick here is a true inflator-combo — that was a deliberate exclusion, because combo tools compromise both jobs. Buy a jump pack from this guide and a separate inflator powered from its DC outlet.
You fly with your tools. Lithium packs are carry-on only and airline limits apply by watt-hours — the GB150 at 88Wh sits close to common limits and the rules are the airlines, not ours. Check before you pack any of the lithium picks.
Final verdict
- Best Overall for Most Cars — NOCO Boost Plus GB40: Check its price
- Fastest Recharge — NOCO Boost X GBX45: Check its price
- Best for Cold Weather — Hulkman Alpha 85S: Check its price
- Best Lithium for Big Engines — NOCO Boost Pro GB150: Check its price
- Strongest Litre Ratings — GOOLOO GT4000S: Check its price
- Best Lead-Acid Shop Box — Clore Jump-N-Carry JNC660: Check its price
Start from your engine and fuel, not from an amp headline: the calculator at the top will land most drivers on the GB40 or GBX45, truck and diesel owners on the Hulkman or GB150, and only genuinely large engines on the GOOLOO. Shops should skip the lithium argument entirely and buy reserve. Head-to-head versions of these choices are in jump starter comparisons, and more truck context is in best truck winches and heavy-duty truck picks.
FAQ
What size jump starter do I need for my engine?
Size by the maker litre rating for your fuel, not by peak amps. A gas car to 6.0L is covered by the GB40; diesels need the lower diesel column, where a 3.0L diesel rating is typical for a compact pack. The calculator at the top of this guide matches litres and fuel to the smallest pick whose rating honestly covers your engine.
Are peak amps a reliable way to compare jump starters?
No. Peak amps are a brief maximum measured differently across brands, and makers rarely publish the conditions. Compare instead the maker engine rating, any published cranking or starting-current figure — the GOOLOO publishes 800A for three seconds, the Clore 425 cranking amps — and the pack energy in watt-hours or amp-hours behind the headline.
Can a jump starter damage my car electronics?
Used as directed, the protected lithium picks here are designed not to: reverse-polarity and spark-proof systems block the classic mistakes. Risk rises when protections are bypassed — manual override and force-start modes disable detection — or when clamps short. Follow the maker connection order, use override only for a battery too flat to detect, and never jump a visibly damaged battery.
How long does a jump starter hold its charge in the car?
Months, not years, and it varies by chemistry and temperature. Lithium packs hold storage charge well but still need scheduled checks; lead-acid boxes like the JNC660 are happiest left on their built-in charger. Every maker here expects periodic recharging, especially after any use. Treat a jump pack like a spare tyre: inspect it on a schedule, not at the roadside.
Can a portable jump starter start a completely dead battery?
Sometimes — that is what override modes are for, when a battery is too flat for the pack to detect. Owner reports in this guide show both outcomes: small packs succeeding with override on ordinary cars, and failing on totally flat large vehicles. A battery that has failed internally, rather than discharged, will not be saved by any pack in this guide.
Is lithium or lead-acid better for a shop?
Lead-acid, on reserve and duty. The JNC660 22Ah battery delivers repeated starts, powers 12V accessories while you work, and can be replaced when it ages — at 18 lb and with no modern ports. Lithium wins everywhere portability matters. Most workshops in the owner sources run both: a lead-acid box at base and a lithium pack in the vehicle.
Can I take a jump starter on a plane?
Lithium jump starters are carry-on items only, never checked baggage, and airlines apply watt-hour limits. The packs here range from 31Wh to 88Wh, so check your airlines exact limit and approval rules for the larger units before travelling. Lead-acid boxes like the JNC660 are not flight luggage at all. Rules change; the airline, not this guide, is the authority.
Why will my jump starter not charge?
The common causes are mundane: a low-wattage charger on a USB-C PD pack, a failed cable, charging outside the packs temperature range, or a pack left flat so long it wakes slowly. Use the maker-spec charger wattage — 60W or 100W PD where the pick expects it — bring the pack to room temperature, and give a deeply flat unit time before judging it dead.
How many jump starts should I get from one charge?
Only maker-stated figures are printed here: up to 20 for the GB40, up to 60 for the Hulkman and GOOLOO, up to 80 for the GB150, with the GBX45 listings conflicting between 6 and 8. Real counts fall with engine size, cold, battery condition and crank time. Plan on far fewer than the headline, and recharge after every use.
Can a jump starter replace jumper cables?
For most single-vehicle emergencies, yes — that is the point of carrying one, and you need no second vehicle. Cables still win in one case: a donor vehicle offers effectively unlimited cranking energy, which matters on hard-starting diesels and destroyed batteries. Many truck owners in the owner sources carry both, a pack for independence and cables as the deep reserve.
Sources & changelog
Manufacturer sources
- NOCO GB40 listing and manual, GBX45 listing and spec table, GB150 listing and datasheet: GB40 on Amazon, GBX45 on Amazon, GB150 on Amazon, GB40 manual, GB150 datasheet
- Hulkman Alpha 85S official specifications and listing: hulkman.com Alpha 85S specifications, Alpha 85S on Amazon
- GOOLOO GT4000S listing and maker specifications: GT4000S on Amazon
- Clore Jump-N-Carry JNC660 listing and specifications: JNC660 on Amazon
Owner sources (paraphrased in the blocks above)
- Bogleheads — portable booster discussion: repeated GB40 use, clamps and override
- IH8MUD — lithium jump starter thread: the GB40 counter-report and overhead argument
- JL Wrangler Forums — GB150 validated and JL Wrangler Forums — NOCO and dead battery (JNC660 reserve discussion)
- AR15.com — GOOLOO GT4000/GT4000S thread: the split owner record, both halves
- TractorByNet — portable jump starter and Yesterdays Tractors — jump box: JNC660 longevity and battery replacement
Changelog — October 15, 2026: guide first published.
By Leo, Founder, WinchInsider
Leo researches vehicle gear the slow way: manufacturer manuals, warranty fine print and owner forums, with every conflict printed rather than smoothed over and no claim of hands-on testing anywhere on the site. Questions and corrections are welcome via our contact page; how affiliate links work is on our affiliate disclosure. More is on our about page.
Related guides
- Portable jump starters — the category hub
- Jump starter comparisons — head-to-head guides
- Best winch battery — sizing and battery health
- Do winches drain battery? Parasitic draws explained
- How long will a winch run on a battery?
- Best portable winch — portable 12V gear, compared