How we researched this guide
We compared the six models in the verified pool behind our pillar guide, then ranked five for everyday drivers — glovebox size, simple clamps, cold-morning reliability and phone charging — and set the heavy lead-acid shop unit aside for this framing. For every pick we used the maker product page or spec table and the Amazon item details, with the ASIN checked on the listing itself, exactly as recorded in the pillar research.
Owner evidence came from Bogleheads, IH8MUD, JL Wrangler Forums, the AR15 forum, TractorByNet and Yesterdays Tractors, paraphrased and linked in each block, including the cautionary reports. We do not test jump starters. Engine ratings are maker ratings, written as rated to, and conflicting listing figures are printed as conflicts. This guide sits under our best portable jump starter pillar in the portable jump starters category, alongside jump starters for emergencies and the head-to-heads NOCO vs GOOLOO and NOCO vs Hulkman.
The 30-second answer
Most drivers should buy the NOCO Boost Plus GB40: rated to 6.0L gas and 3.0L diesel, glovebox-small, with override for a nearly flat battery. Commuters who want a fast USB-C refill should pick the NOCO Boost X GBX45. Cold winters or a large V8? The Hulkman Alpha 85S. A big truck or diesel past the compact ratings? The GOOLOO GT4000S for value, or the NOCO Boost Pro GB150 for reserve and starts per charge.
Best Overall for Most Drivers
NOCO Boost Plus GB40
The default driver pick: 1,000A, rated to 6.0L gas and 3.0L diesel, spark-proof with a manual override, and small enough to live in the glovebox. Best if you drive a car, crossover or small SUV and want the proven compact.
Best for Commuters and Fast Recharge
NOCO Boost X GBX45
The commuter pick: 1,250A, rated to 6.5L gas and 4.0L diesel, with 60W USB-C charging that refills it in under an hour and can be jump-ready in minutes. Best if the pack will also charge your phone and you hate slow refills.
Best for Cold Weather and Larger Engines
Hulkman Alpha 85S
The cold-morning pick: 2,000A, rated to 8.5L gas and 6.0L diesel, with battery pre-heat, a clear status display and a working range the maker rates to -40F. Best if winters are harsh or your engine is a large V6 or V8.
Best Value for Large Engines
GOOLOO GT4000S
The big-engine value pick: 4,000A peak, rated to 12.0L gas and 10.0L diesel, with a screen, 100W USB-C and a DC outlet. Best if your truck or diesel sits past every compact rating and you still want one pack for the household.
Best for Trucks, SUVs and Diesels
NOCO Boost Pro GB150
The heavy-duty driver pick: 3,000A, rated to 9.0L gas and 7.0L diesel, with up to 80 maker-stated starts per charge and a 500-lumen light. Best if you drive a full-size truck or diesel daily and want reserve, not just a rating.
| 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 | 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 USB-C in; DC out | 2 years | |
| GOOLOO GT4000S | 4,000A | 12.0L gas / 10.0L diesel | 100W USB-C PD; DC out | 18 months | |
| NOCO Boost Pro GB150 | 3,000A | 9.0L gas / 7.0L diesel | Micro-USB and XGC in; USB and XGC out | 1 year |
Jump starter size calculator for drivers
Choose your fuel and enter your engine size in litres. We match it only against the maker litre ratings of the five picks in this guide, and recommend the smallest pick whose rating covers your engine. We never recommend a unit below the maker rating for your fuel.
Not sure of your engine size? The vehicle table below lists typical engines drivers actually own. If the same battery keeps dying, a jump pack is not the fix — read why batteries drain and keep the battery healthy with a trickle charger or a pick from budget trickle chargers.
How to choose a jump starter as a driver
Drivers do not need the biggest pack on the shelf. They need a pack that is charged, reachable and honestly rated for their engine on a dark, cold morning. Buy by the maker litre rating for your fuel, keep the safety protections, and treat storage habits as part of the product.
Maker litre rating, not peak amps
Peak amps are a brief headline with no shared test standard, so two packs with very different amp claims can cover the same engine. The litre rating is the comparable figure: match it to your engine and fuel, and leave headroom if the engine is old, the battery is weak or winters are cold. Our calculator applies exactly that rule and never returns a pack below its rating.
Gas vs diesel ratings
Diesels crank harder, so every dual-rated pick here carries a lower diesel figure — the GB40 drops from 6.0L gas to 3.0L diesel, the GT4000S from 12.0L to 10.0L. Diesel drivers must size from the diesel column only. A pack with a generous gas headline and a modest diesel figure is a modest diesel pack, whatever the box emphasises.
Size, weight and where it will live
A pack left in the garage helps nobody at a school gate or office car park. The GB40 and GBX45 are glovebox units at about 2.4 lb and 1.3 lb for the unit itself; the GB150 at 6 lb is a boot or under-seat unit. Choose the size you will actually carry in the car, in its temperature range, all year.
Recharge speed and phone charging
A flat pack is the commonest failure. USB-C Power Delivery picks — the GBX45 at 60W and the GT4000S at 100W — refill in about an hour and double as serious phone chargers. Micro-USB picks refill slowly overnight. Either works if you build the habit: recharge after every use and check the pack on a calendar, not after a failure.
Safety protections and override
The mistake these packs must forgive is a rushed connection in the dark. All five picks publish reverse-polarity protection; the NOCO line adds spark-proof connections. Override and force modes exist for batteries too flat to detect — the GB40 manual override is the proven example — but they bypass detection, so they are a last step used exactly as the maker directs.
Cold-weather behaviour and display
Cold cuts lithium output while engines crank hardest. Published working ranges run from -20C on the NOCO pair to a maker-rated -40F with pre-heat on the Hulkman. A plain-language display, as on the Hulkman and the GT4000S screen, also helps a non-mechanical driver judge pack state without guessing from LEDs.
Typical driver engines by vehicle
Typical factory engines, as sizing examples — check your own engine code before buying. The pick column applies the maker ratings above, the same logic as the calculator.
| Vehicle | Typical engines | Sizing guidance | Pick that covers it |
|---|---|---|---|
| Compact and midsize cars | 1.5 to 2.5L gas | Well inside the smallest rating here | NOCO GB40 |
| Family crossovers and SUVs | 2.0L turbo to 3.6L gas | GB40 covers most; GBX45 adds fast recharge | NOCO GBX45 |
| Large SUVs, gas V8 | 5.3L, 5.7L and 6.2L gas | Past the GB40 comfort zone on a weak battery | Hulkman Alpha 85S |
| Half-ton pickups, gas | V8 gas to 9.0L class use | GB150 reserve suits daily truck use | NOCO GB150 |
| Cars and SUVs, diesel | 2.0 to 3.0L diesel | At the GB40 diesel ceiling — buy headroom | NOCO GBX45 |
| Trucks, diesel | 6.0 to 10.0L diesel | Only the GT4000S rating reaches the top of this band | GOOLOO GT4000S |
Drivers sizing other 12V gear will recognise the discipline from what size winch do I need and winch battery sizing: rate for the real load, not the badge. The emergency-focused ranking is best portable jump starter for emergencies, and the price-tier rankings are jump starters under the mid tier and budget jump starters.
Jump starters by driver priority
| Priority | What you get | Example pick |
|---|---|---|
| One car, no fuss | The proven compact, glovebox size, override included | NOCO GB40 |
| Commute and travel | Fast USB-C refill and real phone charging | NOCO GBX45 |
| Cold winters | Pre-heat, display and the widest working range | Hulkman Alpha 85S |
| Largest engines, value first | The strongest ratings here and a DC outlet | GOOLOO GT4000S |
| Truck driven daily | Most starts per charge and the brightest light | NOCO GB150 |
If portable power beyond the car matters, compare the approach in portable winches and portable 12V winches — different tools, same reserve-versus-weight trade.
Types of jump starter for drivers
| Type | Pros | Cons | Best for |
|---|---|---|---|
| Compact lithium | Glovebox size; simple clamps; phone charging | Smallest reserve; slower refills on Micro-USB models | Most cars — GB40, GBX45 |
| High-output lithium | Ratings for large gas and diesel engines; screens and DC outlets | Heavier; figures conflict more often across listings | Large SUVs, trucks, diesels — Hulkman, GT4000S, GB150 |
| Lead-acid shop unit | Huge reserve for repeated starts; built-in charger | About 18 lb in the pillar pool example; not a glovebox unit | Home garage use — not ranked as a driver pick here |
The lead-acid row is honest about this framing: a shop unit such as the Clore model in our pillar pool suits a garage that starts many vehicles, but everyday drivers are better served by a lithium pack they will actually carry. The full six-model field, including that shop unit, is ranked in the pillar guide.
Detailed reviews: the five driver 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 in maker or listing figures are printed, not smoothed over.
Best Overall for Most Drivers: NOCO Boost Plus GB40
Best Overall for Most Drivers — the proven glovebox compact for cars and crossovers
Why the NOCO GB40 is our pick
The GB40 is the pick most drivers should start with: 1,000A, maker ratings of 6.0L gas and 3.0L diesel, spark-proof protection with a manual override for nearly flat batteries, and the deepest owner record of any compact pack we have researched. It solves the ordinary driver problem — a flat battery away from home — without size, weight or complexity the driver will resent carrying.
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
- 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 and small diesels to 3.0L — the single-car household, the teen driver, the second car. Maker detail is on its Amazon product page and in the GB40 manual. It is also ranked first in our pillar guide.
NOCO GB40 pros and watch-outs
Pros
- Deepest owner record of any pick here
- Manual override for batteries too flat to detect
- Spark-proof, reverse-polarity protection suits first-time users
- IP65 housing with ports closed
- Small enough to live in the car permanently
Watch-outs
- Diesel rating stops at 3.0L
- Micro-USB charging is slow and dated
- No display — LEDs are the whole fuel gauge
- No USB-C fast recharge
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 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. Both reports fit the rating: dependable inside 6.0L gas, out of headroom at the edge.
NOCO GB40: who should not buy
Diesel drivers above 3.0L and V8 drivers who want reserve should not buy the smallest NOCO and hope — read the Hulkman, GT4000S and GB150 blocks below. Drivers who want a sub-hour refill should pick the GBX45 instead.
NOCO GB40: pair it with
Pair it with its fitted NOCO case: the GBC013 EVA protection case is listed for the GB40, keeping clamps and cable together in the glovebox instead of tangled under it.
Check Price — NOCO GBC013 case
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Fitment fineprint: 12V lead-acid vehicles only, within the maker litre ratings above. Ratings are maker claims, not a guarantee on a failed, rather than flat, battery.
Tip: recharge after every use and check on a calendar. Why vehicle batteries fade between drives is covered in why batteries drain.
Best for Commuters and Fast Recharge: NOCO Boost X GBX45
Best for Commuters and Fast Recharge — USB-C fast charge for drivers who live on a schedule
Why the NOCO GBX45 is our pick
The GBX45 is the GB40 idea rebuilt for commuters: a slightly higher rating — 6.5L gas and 4.0L diesel — plus 60W USB-C Power Delivery that refills the pack in a maker-stated 48 minutes and can make it jump-ready in about five minutes from flat. For a driver whose pack also charges a phone on a train-station run, that refill speed is the feature that keeps the pack ready.
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: Up to 6 (Amazon US maker copy) vs up to 8 (Amazon UK) — conflict, printed as found
- Internal battery: 31 Wh lithium-ion
- USB-C: 60W Power Delivery in/out, profiles to 20V/3A
- USB-A output: 5V/2.1A, 10W max
- Safety: Spark-proof connections; reverse-polarity protection (UltraSafe line)
- Housing: IP65
- Light: 100-lumen LED
- Weight: 1.30 lb unit; 2.16 lb with clamps
- Warranty: 1-year limited
NOCO GBX45: fits and best for
Commuters, frequent travellers and crossover drivers with gas engines to 6.5L or diesels to 4.0L, especially anyone who will use the USB-C output daily. Spec detail is reproduced at retailer maker-spec tables for the NOCO Boost line. The brand comparison is our NOCO Boost Plus vs AVAPOW context and the wider NOCO vs Hulkman head-to-head.
NOCO GBX45 pros and watch-outs
Pros
- Fastest sensible refill in the compact class here
- Lightest unit here at 1.30 lb before clamps
- USB-C PD charges modern phones and laptops
- Slightly broader ratings than the GB40
- IP65 housing
Watch-outs
- Starts-per-charge figures conflict between regions
- Micro-USB-era accessories do not carry over
- No status screen
- Priced as a premium compact, by positioning
NOCO GBX45: what owners report
Dedicated long-term owner coverage for the GBX45 is thinner than for the GB40, and we say so rather than borrowing GB40 reports. The closest verified owner record is the compact NOCO discussion on Bogleheads, where owners of the sibling compact report repeated successful use and keeping a pack in each family car — the use pattern this commuter pick is built for.
Drivers comparing the newer Boost X line with the cold-weather alternative should read the owner balance in NOCO vs Hulkman before choosing on recharge speed alone.
NOCO GBX45: who should not buy
If you will never use USB-C charging, the GBX45 premium buys you little over the GB40. Large-engine and larger-diesel drivers are outside its ratings and should read the next three blocks.
NOCO GBX45: pair it with
Pair it with a maintainer for the car it serves: the NOCO GENIUS5 from the verified pool charges and maintains 6V and 12V batteries, so a commuter car that sits at a station all week stops needing jumps.
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Fitment fineprint: 12V lead-acid vehicles within the maker ratings above. The 48-minute refill is a maker figure for the stated USB-C PD input, not a promise with a low-output phone charger.
Tip: keep a USB-C PD charger in the car as well as at home — a five-minute top-up only helps if the right charger is with the pack. See mid-tier trickle chargers for home charging.
Best for Cold Weather and Larger Engines: Hulkman Alpha 85S
Best for Cold Weather and Larger Engines — pre-heat, a clear display and ratings for large engines
Why the Hulkman Alpha 85S is our pick
The Alpha 85S is the driver pick for the hardest ordinary start: a cold morning, a large engine and a driver who wants the pack to say plainly whether it is ready. Its maker rates it to 8.5L gas and 6.0L diesel, with pre-heat technology, a status display, a -40F working floor on the official spec page and a 65W fast recharge. No other pick here combines that cold rating with that display.
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 governs over listing summaries)
- Starts per charge: Up to 60 (maker comparison table)
- Internal battery: Lithium-polymer, 74Wh / 20,000mAh at 3.7V
- USB-C input: SC 65W / PD 18W
- Outputs: USB-C PD 18W; USB-A QC3.0 18W; DC 15V/10A, 150W max
- Display: Status display (maker)
- Operating temperature: -40F to 113F working; storage -40F to 131F
- Dimensions: 9.64 x 4.05 x 1.81 in
- Weight: 2.57 lb product (package weight is higher)
- Warranty: 2-year limited (maker-stated)
Hulkman Alpha 85S: fits and best for
Large cars, SUVs and trucks with gas engines to 8.5L and diesels to 6.0L, and any driver in a cold climate. Official figures are on the Hulkman Alpha 85S reference page, with the manual reproduced at manuals.plus.
Hulkman Alpha 85S pros and watch-outs
Pros
- Widest cold working range here, with pre-heat
- Clear display suits non-mechanical drivers
- Broad gas and diesel ratings in a 2.57 lb pack
- 65W fast recharge; full in about 1.5 hours (maker)
- Longest warranty paper here at 2 years
Watch-outs
- 65W wall charger not included
- Listing summaries conflict with the official diesel and pre-heat figures
- Larger body than the NOCO compacts
- Owner coverage thinner than the GB40 record
Hulkman Alpha 85S: what owners report
Owner and review coverage for the 85S centres on the display, the pre-heat function and the fast recharge, as summarised from its Amazon owner listing; the recurring practical note is that the 65W wall charger is not in the box, so the fast refill needs a charger the driver may have to supply.
Coverage is thinner than the NOCO record — stated plainly. Drivers weighing this pick against NOCO should use our NOCO vs Hulkman head-to-head alongside the official figures above.
Hulkman Alpha 85S: who should not buy
Small-car drivers in mild climates pay for cold technology and engine reach they will never use — the GB40 or GBX45 is the simpler buy. Diesels above 6.0L need the GB150 or GT4000S ratings instead.
Hulkman Alpha 85S: pair it with
Pair it with real jumper cables for the coldest backup: the Energizer 16-foot 6-gauge set from the verified pool covers the day any lithium pack is cold-soaked or flat, via a donor vehicle.
Check Price — Energizer cables
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Fitment fineprint: 12V vehicles within the official maker ratings above. Where listing summaries and the official spec page conflict, this guide prints the official page figures.
Tip: in deep cold, bring the pack indoors overnight rather than leaving it in a frozen boot — the habit behind our maintenance checklist applies to packs too.
Best Value for Large Engines: GOOLOO GT4000S
Best Value for Large Engines — the strongest maker ratings here, with a screen and DC outlet
Why the GOOLOO GT4000S is our pick
The GT4000S is the value answer when a driver engine is simply too large for the compacts: a maker rating of 12.0L gas and 10.0L diesel, a 3.2-inch screen, 100W two-way USB-C, a 400-lumen light and a DC outlet for inflators and 12V gear. It is bought for rating coverage first — with its capacity and warranty conflicts printed in full, as a value brand requires.
GOOLOO GT4000S key specs
- Part number: GT4000S
- Peak current: 4,000A; starting current 800A for 3s (maker spec reproductions)
- Maker engine rating: Gas up to 12.0L; diesel up to 10.0L
- Starts per charge: Up to 60 (maker copy)
- Internal battery: 20,000 mAh (Amazon item details for this ASIN); Wh figures conflict across reproductions — not printed as fact
- USB-C: 100W Power Delivery two-way; full charge about 1.2 hours; 5-minute charge to start (maker)
- Other outputs: DC 15V/10A, 150W; USB QC3.0 18W and 5V/2.4A
- Display: 3.2-inch screen
- Housing: IP65; operating -20C to 60C
- Light: 400-lumen LED
- Weight: About 4.9 lb (maker spec reproductions)
- Warranty: 18 months (Amazon item details; some reproductions print 2 years — conflict)
GOOLOO GT4000S: fits and best for
Drivers of large gas trucks and SUVs, and diesels to 10.0L, plus mixed households whose biggest vehicle rules out the compacts. Maker spec detail is reproduced at GT4000S spec reproduction. The brand head-to-head is our NOCO vs GOOLOO guide.
GOOLOO GT4000S pros and watch-outs
Pros
- Strongest maker ratings in this guide, gas and diesel
- Screen reports pack state in plain view
- 100W USB-C is the fastest refill here
- DC outlet powers separate inflators
- Over 1,000-cycle service-life claim
Watch-outs
- Capacity in watt-hours conflicts across reproductions
- Warranty figures conflict (18 months printed from item details)
- Heaviest lithium pick here at about 4.9 lb
- Owner reports include charging faults on some GT-line units
GOOLOO GT4000S: what owners report
On the AR15 forum, owner reports are mixed in a useful way: some owners report GT-line charging issues and error codes, others report many units faultless with diesel and equipment starts. Both sides are printed here because a value pick should be bought with its record visible.
An Amazon owner report, via maker-spec reproductions in the pillar research, describes a unit failing to crank a nearly dead 5.3L V8 where a smaller NOCO succeeded, plus awkward side-post clamp fit. Treat clamp seating as part of the job on any pack, and keep the receipt and warranty paper for this brand.
GOOLOO GT4000S: who should not buy
If your engine is inside GB40 or GBX45 ratings, the extra reach buys weight and listing conflicts, not better mornings. Drivers who want the longest, cleanest owner record should pay for the NOCO line instead.
GOOLOO GT4000S: pair it with
Pair it with the GB40 for the second household car: the GT4000S covers the big engine, the GB40 lives in the family car, and neither vehicle borrows the other pack on the morning both are needed.
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Fitment fineprint: 12V lead-acid vehicles within the maker ratings above. Hybrid fitment is not claimed in the material checked — confirm your model jump points before use.
Tip: photograph the screen state after a full charge when the pack is new, so a later fault is easy to describe under warranty. More pack-care context sits with essential accessories.
Best for Trucks, SUVs and Diesels: NOCO Boost Pro GB150
Best for Trucks, SUVs and Diesels — reserve and starts per charge for vehicles driven hard, daily
Why the NOCO GB150 is our pick
The GB150 is the driver pick for a full-size truck, large SUV or diesel that is used every day: 3,000A, ratings of 9.0L gas and 7.0L diesel, up to 80 maker-stated starts per charge from an 88Wh pack, and a 500-lumen light for roadside work. It is not a glovebox unit — at 6 lb it lives under a seat or in the boot — and that reserve is exactly its point.
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 (datasheet)
- Charging inputs: Micro-USB 5V/2.1A; XGC 12V/5A
- Outputs: USB 5V/2.1A; XGC 12V/15A
- Safety: Spark-proof connections; reverse-polarity protection (UltraSafe line)
- Housing: IP65 (ports closed)
- Operating temperature: -20C to +50C; charging 0C to +40C
- Light: 500-lumen LED
- Weight: 6 lb unit; 7.5 lb with clamps and accessories
- Warranty: 1-year limited
NOCO GB150: fits and best for
Full-size pickups, large SUVs and diesels to 7.0L driven daily, plus drivers who help others at the roadside. Datasheet detail is in the GB150 datasheet via manuals.plus. Truck drivers will also use our truck winch guide and F-150 winch picks for the rest of the kit.
NOCO GB150 pros and watch-outs
Pros
- Most starts per charge here by a wide margin
- Brightest light here at 500 lumens
- XGC port for faster 12V charging and output
- Broad gas and diesel ratings with NOCO protections
- Proven on a dead-aux-battery Jeep in owner reports
Watch-outs
- 6 lb unit is not a glovebox pack
- Micro-USB refill is slow for an 88Wh pack
- USB device charging is the older 2.1A generation
- Oversized for a small car driven gently
NOCO GB150: what owners report
On JL Wrangler Forums, an owner validated a GB150 starting a JL with a dead auxiliary battery quickly after an overnight charge — the exact dual-battery confusion that strands modern truck and SUV drivers. Related NOCO dead-battery discussion is on the same forum at NOCO and dead battery.
The pillar research also records an owner report, via retailer reproduction, of a cold-day diesel tractor start after a month stored in the truck, with slow USB charging noted as the trade — consistent with the spec list above.
NOCO GB150: who should not buy
Small-car drivers should not carry 6 lb of reserve they will never use — the GB40 does the same job in a glovebox. Diesel drivers above 7.0L need the GT4000S rating, not this pack and hope.
NOCO GB150: pair it with
Pair it with a maintainer sized for a truck battery: the NOCO GENIUS5 from the verified pool keeps a daily-driven truck battery topped up at home, so the GB150 becomes the backup, not the routine.
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Fitment fineprint: 12V lead-acid vehicles within the maker ratings above. Weight figures are unit and with-accessories figures from the datasheet — plan storage for the larger one.
Tip: store the GB150 under a seat, not in a hot boot in summer, and top it up after any roadside help you give. Battery-load background is in how long a battery carries a load and how many amps a 12V load draws.
Spec comparison
All five driver picks side by side, on maker-published figures only. Where a maker publishes nothing, or listings conflict, the cell says so.
| Spec | GB40 | GBX45 | Alpha 85S | GT4000S | GB150 |
|---|---|---|---|---|---|
| Peak current | 1,000A | 1,250A | 2,000A | 4,000A | 3,000A |
| Gas rating | 6.0L | 6.5L | 8.5L | 12.0L | 9.0L |
| Diesel rating | 3.0L | 4.0L | 6.0L | 10.0L | 7.0L |
| Internal battery | Lithium-ion, Wh not published | 31 Wh lithium-ion | 74Wh lithium-polymer | 20,000 mAh; Wh conflicts | 88 Wh lithium-ion |
| Starts per charge (maker) | Up to 20 | 6 to 8 (conflict) | Up to 60 | Up to 60 | Up to 80 |
| Fastest recharge | Micro-USB | 60W USB-C PD, 48 min | 65W USB-C | 100W USB-C PD | XGC 12V |
| Device output | USB 2.1A | USB-C PD and USB-A | USB-C, USB-A and DC | USB-C, USB and DC | USB and XGC |
| Operating temperature | -20C to +50C | Not published | -40F to 113F | -20C to 60C | -20C to +50C |
| Weight | 2.4 lb | 1.30 lb unit | 2.57 lb | About 4.9 lb | 6 lb unit |
| Warranty | 1 year | 1 year | 2 years | 18 months | 1 year |
| Check Price |
Fitment & installation basics
There is nothing to install — fitment means matching the pack to the vehicle before the bad morning, and the connection order when it comes. Connect red to the positive terminal, then black to a solid unpainted ground on the engine or chassis away from the battery. Power the pack on, wait for its ready indication, and crank in short attempts. Remove the clamps in reverse order once the engine runs.
Driver fitment notes: side-post batteries punish shallow clamp contact on any pack, so seat clamps deliberately and check the alert lights before cranking. Dual-battery diesels and modern vehicles with auxiliary batteries — the case in the GB150 owner report above — may need the pack left connected briefly before a crank attempt. A hybrid is jumped only at its published 12V jump points, never at the traction battery. Store the pack in the cabin, not a hot boot, so it stays inside its temperature range. Drivers fitting other kit — Wrangler winches or a recovery kit — should keep the jump pack reachable, not buried under it.
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 override or force mode 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 store any pack in a hot closed vehicle beyond its rating.
- A swollen, cracked, hot or leaking pack is finished — do not charge it, jump with it, or store it indoors near exits.
NOCO GBC013 case — the fitted EVA case listed for the GB40 in the verified pool, so clamps and cable stay together. The full category is our portable jump starters archive.
Check Price — NOCO GBC013 case
NOCO GENIUS5 maintainer — the verified-pool 5A charger and maintainer that stops a weak vehicle battery needing jumps in the first place; compare trickle charger picks, Battery Tender vs Schumacher and battery sizing and health.
Energizer jumper cables, 16-foot 6-gauge — the verified-pool donor-vehicle backup for the day a pack is flat or an engine defeats it; the wider kit list is in essential accessories.
Check Price — Energizer cables
Troubleshooting
| Symptom | Likely cause | Fix |
|---|---|---|
| Clicks but no crank | Weak clamp contact, a battery too flat to detect, or a pack below its rating for that engine | Reseat clamps on clean metal, check pack charge, leave it connected a minute, then use the maker override mode only as directed — and if the engine is above the pack rating, use a bigger pick from this guide |
| Pack will not switch on or take charge | Pack deeply discharged in storage or charging outside its temperature range | Bring it indoors to room temperature, use the maker cable and a charger of the right output, and leave it connected — deeply flat packs can take time to wake |
| Clamp alert or error on the display | Reverse polarity, shorted clamps, or a vehicle battery fault | Remove both clamps, check terminal markings in daylight, reconnect in the correct order; a repeated alert on a correct connection points at the vehicle battery |
| Starts once, then nothing on the second attempt | Reserve spent by repeated cranks, device charging, or a cold-soaked pack | Recharge fully before judging the pack; in cold, warm a lithium pack indoors first, and charge the vehicle battery properly between attempts |
| Swollen or hot 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 pack did its job — the vehicle needs a battery or charging-system repair, ideally with a maintainer from the safety section, not a bigger pack |
Who should NOT buy these
Your diesel is above 10.0L, or your system is 24V. Nothing here is rated for you — the strongest diesel rating stops at 10.0L and every pick is a 12V unit. Compare the full field in our pillar guide instead of guessing bigger inside this page.
You need a garage unit for repeated daily starts. These are driver packs, not workshop units. A garage that starts many vehicles should use the lead-acid shop class ranked in the pillar guide — heavy, mains-kept and built for reserve — rather than cycling a glovebox lithium pack to death.
Your battery is failing, not flat. A jump pack 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 a maintainer first.
You will not maintain a pack. Every unit here 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 the standby claim on the box says.
You fly with your tools. Lithium packs are carry-on only and airlines apply watt-hour limits, which matter most for the 74Wh and 88Wh picks here. Check your airline rules before travelling, and never pack any of them in checked baggage.
Final verdict
- Best Overall for Most Drivers — NOCO Boost Plus GB40: Check its price
- Best for Commuters and Fast Recharge — NOCO Boost X GBX45: Check its price
- Best for Cold Weather and Larger Engines — Hulkman Alpha 85S: Check its price
- Best Value for Large Engines — GOOLOO GT4000S: Check its price
- Best for Trucks, SUVs and Diesels — NOCO Boost Pro GB150: Check its price
Start from your engine and fuel, not from an amp headline: the calculator at the top lands most car drivers on the GB40, commuters on the GBX45, cold-climate and large-engine drivers on the Hulkman, the largest diesels on the GT4000S, and daily truck drivers on the GB150.
FAQ
What is the best portable jump starter for most drivers?
On maker ratings and owner record, the NOCO Boost Plus GB40: 6.0L gas and 3.0L diesel coverage in a 2.4 lb glovebox pack, with spark-proof protection and a manual override. Drivers who want a fast USB-C refill trade up to the GBX45; drivers with larger engines or diesels size up through the calculator, never by peak amps.
How do I size a jump starter for my car?
Find your engine size in litres and your fuel, then choose the smallest pack whose maker rating for that fuel covers it, with headroom for age and cold. A 2.5L gas car is well inside every pick here; a 3.0L diesel sits exactly at the GB40 diesel ceiling, so the honest buy is the next rating up — the GBX45, Hulkman or above.
Can a portable jump starter start a diesel?
Yes, within its diesel rating — and only there. In this guide the diesel column runs from 3.0L on the GB40 to 4.0L on the GBX45, 6.0L on the Hulkman, 7.0L on the GB150 and 10.0L on the GT4000S. Always size a diesel from the diesel figure, never the gas headline, and give a dual-battery truck a moment connected before cranking.
How long will a jump starter hold its charge in the car?
Every lithium pack self-discharges, faster in heat. The safe habit is the same for all five picks: recharge after every use, then check and top up on a calendar — monthly is a sensible driver rhythm, and always before a long trip. A pack stored in a hot boot ages faster and holds less, so cabin storage inside its temperature range is part of the answer.
What does the override or boost mode do?
It lets the pack deliver a jump when the vehicle battery is too flat for the pack to detect, which is the case standard detection refuses for safety. The GB40 manual override is the proven example in this guide. Because the mode bypasses detection, it is a last step: confirm clamp polarity in daylight first, and follow the maker instructions exactly.
Can I charge my phone from a jump starter?
Yes — all five picks offer USB output, but the experience differs. The GBX45 and GT4000S use USB-C Power Delivery that charges modern phones fast and refills the pack itself quickly; the GB40 and GB150 offer older 2.1A USB, fine for a top-up. Remember that phone charging spends the same reserve you may need for a start, so recharge the pack afterwards.
Are larger jump starters always better for drivers?
No. A larger pack brings reserve and broader ratings, but also weight that pushes it out of the glovebox and into the boot, where it is forgotten and heat-aged. The right driver pack is the smallest one whose maker rating honestly covers your engine with headroom — which is why this guide ranks a 2.4 lb compact first and a 6 lb unit last, for different drivers.
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 larger picks here are 74Wh and 88Wh units, so check your airline exact limit and any approval rule before travelling. Never travel with a swollen or damaged pack at all, by any route.
When should a driver skip a jump starter and call for help?
When the battery is swollen, cracked, leaking or hot; when repeated correct attempts produce only heat or smell; when warning lights point to a charging-system failure rather than a flat battery; or when you cannot safely reach a ground point away from the battery. A pack is for a flat battery in a sound vehicle — everything else is a repair, not a jump.
Sources & changelog
Manufacturer sources
- NOCO GB40, GBX45 and GB150 listings, manual and datasheet: GB40 on Amazon, GBX45 on Amazon, GB150 on Amazon, GB40 manual, GB150 datasheet
- Hulkman Alpha 85S official reference and listing: Hulkman reference 85S, Alpha 85S on Amazon, Alpha 85S manual
- GOOLOO GT4000S listing and spec reproductions: GT4000S on Amazon, GT4000S spec reproduction
Owner sources (paraphrased in the blocks above)
- Bogleheads — portable booster discussion: compact NOCO use, clamps and override
- IH8MUD — lithium jump starter thread: the compact-pack overhead counter-report
- JL Wrangler Forums — GB150 aux-dead start and NOCO and dead battery
- AR15 forum — GOOLOO GT4000 and GT4000S: mixed GT-line owner record
- TractorByNet — portable jump starter and Yesterdays Tractors — jump box: reserve and long-service context
Changelog — October 17, 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
- Best portable jump starter — the pillar guide
- Portable jump starters — the category hub
- Best portable jump starter for emergencies
- NOCO vs GOOLOO jump starter — head-to-head
- Best trickle charger — keep the battery from dying
- Best winch battery — sizing and battery health