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Best jump starters: engine ratings, start limits and safety in each manual
Compare engine rating, start limits and charging limits on each maker’s own figures
The makers quote different amp figures (start assist, cranking, starting and peak), and none of the documents read says how they are measured, so start from the engine rating. Clore’s page rates the JNC325 at 450 start assist amps for up to 8L gasoline and 6L diesel engines; Clore’s own page title (“2000A/450SAA”) and Amazon’s title also carry 2000A, a figure the manual does not give.
Clore lists the JNC770R at 1700 peak and 425 cranking amps and publishes no engine size. GOOLOO’s manual gives the GP4000 4000A peak and 800A starting current and says it can start “all gasoline engines and diesel engines up to 10.0L”.
The table below lists all 26 models, each with its own guide. Six are NOCO models; none is picked here because all six Amazon listings read “Currently unavailable” when this section was checked on September 29, 2026.
For NOCO's 1000A GB40, which sits between the GB20 and the GBX45, see our NOCO GB40 guide.
Starts in a row differ. Clore’s manuals say that if the engine does not start within 6 seconds, let the unit cool for 3 minutes, and the JNC325 manual says not to try after four attempts. GOOLOO says no more than three consecutive starts, two minutes apart, and 30 minutes of cooling before recharging. AstroAI says to allow a 60-second break between uses. For charge level, GOOLOO asks for more than two bars, AstroAI for above 75 percent and Clore’s JNC325 manual for at or near 100 percent.
Temperature limits differ. The JNC325 manual gives -10 to 140°F for operation and 40 to 140°F for charging. GOOLOO gives -4 to 140°F for operation and says to charge only between 14 and 113°F. AstroAI gives -4 to 122°F and 32 to 113°F. Both Clore manuals say not to store the unit below 50°F when using it as a jump starter and never to charge or jump start a frozen battery.
Override and BOOST buttons change how the unit behaves. Clore says that activating the JNC325 override removes all safety from the unit, so check every connection and that the only problem is a totally dead battery. GOOLOO says to press BOOST only after the clamps are connected correctly and to start within 30 seconds. AstroAI says not to press Boost before connecting to the car battery.
Both Clore manuals warn that car, truck and boat lead-acid batteries give off hydrogen gas that may violently explode near fire or sparks. They say to work in a well-ventilated area, not to smoke near batteries and to wear eye protection.
All four manuals say never to let the two clamps touch and to disconnect once the engine starts. GOOLOO says the GP4000 is for 12V vehicles only and forbids use on other machines such as aircraft and boats, though its highlights list yachts. AstroAI says not to use the S8 Ultra on non-12 V vehicles, such as airplanes and other 24 V vehicles/boats.
GOOLOO and AstroAI add stop-use lines for their lithium packs. GOOLOO says not to use the GP4000 if it is overheated, swelled or leaking, or to store it in a vehicle parked in hot weather for long periods. AstroAI says to switch the S8 Ultra off, remove the clamps and contact support if it overheats, smokes or burns, and to take off metal accessories such as rings first.
A lead-acid pack for the shop: Clore Jump-N-Carry JNC770R
Clore lists a sealed lead-acid battery, 68-inch leads and 23 lb. The manual says the unit can stay connected to AC power indefinitely, and to charge it for 24 hours out of the box, then again after every use. The display shows Er1 for reverse polarity and Er2 for a battery above 16VDC. Clore’s one-year warranty needs a dated sales receipt: failures in the first 30 days go back to the place of purchase, and days 31 to 365 go to Clore.
Read the JNC770R guide · Check the JNC770R on Amazon
A lithium pack with an override button: Clore Jump-N-Carry JNC325
Clore’s manual gives a 14.8V/74Wh lithium pack, and its page gives 4.3 lb and two USB outlets. To override the safety circuit, hold the button for more than 3 seconds but less than 6. The manual says the battery cannot be replaced, that a new unit needs at least 6 hours of charging and that the pack needs charging every three months. Clore’s warranty page gives the same one-year, dated-receipt terms for Jump-N-Carry units.
Read the JNC325 guide · Check the JNC325 on Amazon
A diesel rating up to 10.0L: GOOLOO GP4000
GOOLOO’s manual lists a 74Wh/5000mAh pack, while an older manual copy on the listing says 99.2Wh. The manual says not to start a vehicle while the unit is charging and to store it below 140°F. The manual gives an 18-month warranty; GOOLOO’s policy lists 18+6+6 months, excludes products bought through an online auction house and points to a separate warranty policy we did not find. Its claim form lists Amazon among the places you can have bought it and says a newsletter sign-up is required for an extra 6 months.
A 4000A pack with two engine ratings: AstroAI S8 Ultra
AstroAI’s page lists 10.0L gas and 8.0L diesel for this model and “All Gas/12L Diesel” for the S8 Ultra Max; Amazon’s title gives this model the Max’s rating. The manual gives 59.2Wh (4000mAh at 14.8V), while the page says 24000 mAh. Amazon’s bullets claim IP65; no AstroAI document read gives an IP rating. The two-year warranty covers the original purchaser only.
Read the S8 Ultra guide · Check the S8 Ultra on Amazon
Before you buy or use
- Recalls. CPSC’s database, searched September 29, 2026, lists no recall naming Clore, Jump-N-Carry, GOOLOO or an AstroAI jump starter; AstroAI’s one recall is a 2025 minifridge. Other brands’ recalled packs include Whistler Jump&Go and Jackco ZETA (2015) and Eastwood’s Rockwood pack (2016). Check cpsc.gov again before you order.
- Who sold it. Clore needs a dated sales receipt and GOOLOO excludes auction-house purchases. AstroAI covers the original purchaser only. Ask each maker whether your Amazon seller qualifies.
Based on published specifications, manuals and warranty terms, not usage tests. Sources checked September 29, 2026: Clore JNC770R (cloreautomotive.com) and its manual (cloreautomotive.com), JNC325 (cloreautomotive.com) and its manual (cloreautomotive.com), Clore warranty and repairs (cloreautomotive.com), GOOLOO GP4000 (us.gooloo.com) and its manual (cdn.shopify.com), GOOLOO policy (us.gooloo.com) and claim form (us.gooloo.com), AstroAI S8 Ultra (astroai.com) and its manual (help.astroai.com). Amazon links are affiliate links.
Compare every model in this category
Each row says who the model suits, its main strength and its main catch, taken from each guide's listed sources. Open a guide to confirm the exact model and what's included before you buy on Amazon.
| Product | Best for | Main strength | Main caveat |
|---|---|---|---|
| NOCO Boost GB20 500A 12V Lithium Jump Starter | Gas engines up to 4.0 litres, motorcycles and powersport | Spark-proof and reverse-polarity protection in normal use, with an IP65 housing | NOCO's own spec sheet lists diesel as Not Recommended, and gas only to 4.0 L |
| GOOLOO GP4000 4000A 12V Jump Starter | Gas engines and diesels up to 10.0 L, plus 12V accessory power | Smart cable reads out connection, reverse polarity and low voltage on one light | Three published battery capacities for one model: 74Wh, 99.2Wh and 24000 mAh |
| GOOLOO A3 3000A Jump Starter with Air Compressor | One glovebox tool for a flat battery and a soft tire | Jump starter and a 150 PSI auto-stop inflator in one body, with five preset modes | Only three consecutive starts, two minutes apart, per GOOLOO's guide |
| GOOLOO GP3000 3000A Lithium Jump Starter | A glovebox 12-volt pack that also runs a 150-watt DC accessory | Manual publishes watt hours, port ratings and charge time for this model | Manual forbids boat use that the listing and maker page advertise |
| GOOLOO G7 3000A Jump Starter with Built-In USB-C Cable | Drivers who want one pocket device for starting and phone charging | Built-in 45-watt USB-C cable means no separate lead to carry | Capacity is stated two different ways and neither source reconciles them |
| GOOLOO GT3000 3000A 12V Jump Starter | A light glovebox pack that doubles as a 65-watt USB-C power bank | Two-way 65-watt USB-C fills the pack in about fifty minutes | The 65-watt charger that makes the 0.8 hour claim work is not included |
| GOOLOO GT4000S 4000A 12V Jump Starter | Larger engines plus a 150-watt DC accessory port in one pack | Box includes a 100-watt car charger and a cigarette lighter adapter | DC port cannot recharge the pack, which the manual states outright |
| Clore Automotive Jump-N-Carry JNC660 1700 Peak Amp 12V Jump Starter | Shop and roadside 12-volt starting plus 12-volt accessory power | Automatic-charging models may stay connected continuously, the manual states | The manual covers two JNC660 builds, and only the newer one resists overcharging |
| Clore Automotive Jump-N-Carry JNC770R Premium 12V Jump Starter | Long-reach shop starting with USB and 12-volt accessory power | Manual says it may stay connected to AC power indefinitely on its automatic charger | The 23 lb lead-acid pack needs 24 hours of charging out of the box and a recharge after every use |
| Clore Automotive Jump-N-Carry JNC325 12V Lithium Jump Starter | Starting 12V vehicles up to 8L gas or 6L diesel, plus USB power | Override function for a battery at 0.0 volts, per Clore's page | Manual says the internal battery cannot be replaced once it is finished |
| Clore Automotive Jump-N-Carry JNC305 12V Lithium Jump Starter | Passenger cars, powersports and marine starting up to 6L gas | Override is rated to engage a battery at 0.0 volts, per Clore and the manual | Manual says the internal battery cannot be replaced once it is finished |
| TOPDON JumpSurge JS3000 3000A 12V Lithium Jump Starter | Larger 12-volt engines to 9L gas or 7L diesel, plus USB-C power | TOPDON publishes a full port and output table in its JS3000 product profile | Four starts in ten minutes triggers a lockout that blocks all output for ten minutes |
| AstroAI S8 Ultra 4000A 12V Lithium Jump Starter | Compact 12-volt starting with USB-C power-bank duty | Smart clamps signal correct connection, reversed polarity and a low battery | Engine rating differs: the listing claims all gas and 12L diesel, AstroAI's page says 10L and 8L |
| AstroAI S8 1500A 12V Lithium Jump Starter | Glovebox-sized starting for 6L gas or 3L diesel engines | Smart clamps signal correct connection, reversed polarity and a low battery | Two AstroAI S8 manuals disagree on capacity, 29.6 Wh against 37 Wh |
| Schumacher SJ1332 Jump Starter and Power Station | Drivers who want one lead-acid box for 12-volt jump starts up to 8.0L gas or 6.0L diesel, tyre top-ups and a small AC load of up to 200 continuous watts. | Schumacher publishes a full specification table for this exact model, including a 370 cranking amp figure the listing never mentions. | The manual attached to the listing is headed MODEL: SJ1330 and its specifications section says nothing about the AC outlets or the converter. |
| GOOLOO GT4000 Arctic Jump Starter | Drivers who want a 4000-amp 12-volt jump pack with a preheating mode and are willing to check the cold-weather numbers with GOOLOO first. | The 4000-amp peak appears on the listing, the page and the manual, and the manual adds an 800-amp starting figure. | The -40 pre-heating claim sits next to a -4F to 140F operating range in both GOOLOO's manual and its FAQ. |
| GOOLOO GT6000 Jump Starter (JS-271) | 12V gas vehicles and diesel engines up to 12.0L, with laptop charging | 6000A peak for 12V gas and diesel up to 12.0L, per GOOLOO | Fast 1.4-hour recharge needs a wall charger sold separately |
| NOCO Boost Pro GB150 3000A 12V Lithium Jump Starter | Gas engines to 9.0L and diesels to 7.0L, with a voltmeter on board | Built-in voltmeter reads the vehicle battery when the clamps are connected | Peak rating is 3000 A on NOCO's pages but 4000 A in the attached guide |
| NOCO Boost GB70 2000A 12V Lithium Jump Starter | Gas engines to 8.0L and diesels to 6.0L on 12V lead-acid batteries | Spark-proof and reverse-polarity protected in normal use, in an IP65 housing | Guide says Micro USB input; NOCO's specs page and listing say USB-C |
| NOCO Boost X GBX155 4250A 12V Lithium Jump Starter | Gas engines to 10L and diesels to 8.0L, with a 60 W USB-C charger on hand | Guide publishes a recharge table for four charger sizes | Box lists differ: NOCO names a 12V to USB-C cable, the listing a fast charger |
| NOCO Boost X GBX55 1750A 12V Lithium Jump Starter | Gas engines to 7.5L and diesels to 5.0L, recharged from USB-C | Recharges in 1.2 hours from a 60 W USB-C charger, per NOCO | No wall charger in the box; the fast figures need a 60 W USB-C charger |
| NOCO Boost X GBX45 1250A 12V Lithium Jump Starter | Gas engines to 6.5L and diesels to 4.0L, recharged from USB-C | 48-minute full recharge from a 60 W USB-C PD charger, per NOCO | No wall charger in the box; fast charging needs a 60 W USB-C PD 3.0 charger |
| DEWALT DXAELJ16 1600A Lithium Jump Starter with USB Power Bank | Most cars and trucks with 4, 6 or 8 cylinder engines, per DEWALT's page | AC, DC and USB charging all come in the box, per the manual and maker | Manual allows a second try after a 4-5 minute rest, then says stop |
| DEWALT DXAELJ18C 1800A Lithium Jump Starter with USB-C Power Bank | Most cars and trucks with 4, 6 or 8 cylinder engines, charged over USB-C | USB-C PD charging in and out at up to 30W, per the manual | No wall adapter in the box; the manual asks for a Class 2 USB adapter |
| DEWALT DXAEPS14 2000 Peak Amp Jump Starter with Air Compressor and AC Outlets | Drivers who want one box to jump-start, inflate tires and run small 120V loads | One box covers jump-starting, tire inflation, 500W AC and USB charging | Sealed lead-acid pack: 40-hour first charge and a recharge every 30 days |
| Schumacher Electric SL1690 2000A Peak Lithium Jump Starter and Power Pack | Gas engines up to 9.0L or diesel up to 7.0L, per Schumacher's page | Rated for gas engines up to 9.0L and diesel up to 7.0L, per Schumacher | Page claims IP65 (its spec table says No Rating); the manual omits IP65 and Pre-Boost |
What to check before buying
The jump starter guides here compare the peak-amp and engine-size claims on each listing with the maker's own documents, and convert battery capacity to watt-hours where the sources disagree. They quote each manual's limit on starts in a row, the temperatures at which the pack may be charged, and whether a wall charger comes in the box.
- Engine size and amps. Check the engine sizes the maker states, not just peak amps. Guides report diesel listed as not recommended on one model, a listing claiming larger engines than the maker's page, and peak or starting-current figures that differ between the maker and the listing.
- Capacity in watt-hours. Listings often quote large mAh figures while manuals give watt-hours at 14.8 V. Guides report 44.4 Wh against a listed 12,000 mAh, 74 Wh against 20,000 mAh, and two maker manuals for one model with different capacities.
- Starts in a row. Manuals cap consecutive starts. Guides report three starts two minutes apart, five starts in 15 minutes followed by a rest, a four-start lockout in ten minutes, and one manual that gives two different limits.
- Charging window and charger. Packs often charge only in a narrower temperature band than they operate in, such as 32 to 113°F. Several guides note that the wall charger behind a fast-charge claim is not in the box.
- Lead-acid upkeep. The lead-acid units here want charging after every use and at least every 30 days to three months, and one guide reports a full charge taking up to 24 hours. Two listings supply a manual written for other model numbers.
This page collects 26 jump starter guides from Plain Buy Guides. Each guide covers one exact Amazon listing: the maker's published specifications, what the listing says is included, the fit and installation limits that decide whether it suits you, and the main caveat, with every source listed and dated. Nothing here is based on hands-on testing, and no guide promises a price or stock level.
In the table above, the Best for column says who each model suits, and the strength and caveat columns carry the first point each guide makes. Open a guide before buying to confirm the exact model, the included parts and any conflict between the listing and the maker's documents, which each guide reports rather than settles. Side-by-side pages put the published facts of two models from this category in one place.
Compare the published specs
The main figures stated in each jump starter guide on this page, side by side, with each guide's sources behind them. Units are as published; nothing here was measured by us.
A table scrolls sideways when it is wider than the screen. Select a column heading to sort.
— means the guide does not state that figure. n/a means the figure does not apply to that model. “or” means the guide states more than one figure, for example where two sources disagree, for different modes or versions, or where a kit includes two tools; open the guide to see which applies. † means the guide reports that another source gives a different figure, or doubts the figure; open the guide. Only single figures in the column’s unit, with no mark, word or note in brackets, are sorted and counted below.
By the numbers
These cover only the 26 jump starters on this site, not the whole market. Ranges use the figures the guides state; the lowest and highest link to their guides, and the median is the middle of those figures. A model whose figure is missing, not applicable, more than one, marked, in words, in another unit or qualified in brackets is left out of that line.
- Peak current across the 23 of our 26 jump starters that state one figure: 500 A to 6,000 A, median 2,000 A. Lowest: NOCO Boost GB20 500A 12V Lithium Jump Starter. Highest: GOOLOO GT6000 Jump Starter (JS-271).
- Battery across the 16 of our 26 jump starters that state one figure: 24 Wh to 99.9 Wh, median 51 Wh. Lowest: NOCO Boost GB20 500A 12V Lithium Jump Starter. Highest: GOOLOO GT6000 Jump Starter (JS-271).
- Gas engines up to across the 15 of our 26 jump starters that state one figure: 4 L to 12 L, median 8 L. Lowest: NOCO Boost GB20 500A 12V Lithium Jump Starter. Highest: GOOLOO GT4000 Arctic Jump Starter.
- Diesel engines up to across the 15 of our 26 jump starters that state one figure: 3 L to 10 L, median 6 L. Lowest: Clore Automotive Jump-N-Carry JNC305 12V Lithium Jump Starter and 1 other. Highest: GOOLOO GP4000 4000A 12V Jump Starter and 1 other.
Read the full Liters Not Amps buying guide (liters-not-amps.pages.dev).
- NOCO Boost GB20 500A 12V Lithium Jump Starter
NOCO GB20 guide: 500 A peak for gas engines to 4.0L, diesel not recommended, powersport clamps, the five-starts rule and what manual override switches off.
- GOOLOO GP4000 4000A 12V Jump Starter
GOOLOO GP4000 guide: 4000 A peak for gas and 10L diesel, a three-start limit with two-minute gaps, a 30-minute cool-down, and two maker capacity figures.
- GOOLOO A3 3000A Jump Starter with Air Compressor
GOOLOO A3 (JS-506) guide: 3000 A for 9.0L gas and 6.5L diesel, a three-start limit with two-minute gaps, a 150 PSI inflator, a 44.4Wh battery and two warranty terms.
- GOOLOO GP3000 3000A Lithium Jump Starter
GOOLOO GP3000 jump starter guide: the manual's 59.2 Wh capacity against the listing's 16,000 mAh, the 150 W DC port, charging limits and 18-month cover.
- GOOLOO G7 3000A Jump Starter with Built-In USB-C Cable
GOOLOO G7 jump starter guide: the manual's 44.4 Wh against the listing's 12,000 mAh, the 45 W built-in cable, charging limits and the 18-month terms.
- GOOLOO GT3000 3000A 12V Jump Starter
GOOLOO GT3000 jump starter guide: the manual's 44.4 Wh and 1.32 lb, the 65 W two-way port, the narrower 131 F limit, and what is really in the box.
- GOOLOO GT4000S 4000A 12V Jump Starter
GOOLOO GT4000S guide: the manual's 74 Wh and 800 A starting current, the 150 W output-only DC port, the box list, and a part number shared with two models.
- Clore Automotive Jump-N-Carry JNC660 1700 Peak Amp 12V Jump Starter
The Jump-N-Carry JNC660 is a 1700 peak amp lead-acid jump starter. Clore's manual splits charging rules between auto-charging and older no-LED units.
- Clore Automotive Jump-N-Carry JNC770R Premium 12V Jump Starter
The Jump-N-Carry JNC770R pairs 1700 peak amps with a 7-segment display, dual USB and a master switch. Clore's manual gives one charging method only.
- Clore Automotive Jump-N-Carry JNC325 12V Lithium Jump Starter
Clore's JNC325 page leads with 450 start assist amps where the listing says 2000A. The manual gives 74 Wh, a 6-hour first charge and no user battery swap.
- Clore Automotive Jump-N-Carry JNC305 12V Lithium Jump Starter
Clore gives the JNC305 1000A and 300 start assist amps from a 37 Wh pack. Its manual caps charging at 32 to 108F and says the battery cannot be replaced.
- TOPDON JumpSurge JS3000 3000A 12V Lithium Jump Starter
TOPDON rates the JS3000 at 3000 peak amps on an 88.8 Wh pack. Its support pages add a four-start lockout in ten minutes and a 10-second auto shutdown.
- AstroAI S8 Ultra 4000A 12V Lithium Jump Starter
AstroAI's S8 Ultra manual gives 59.2 Wh and two USB-A ports. Its own product page says 24000 mAh and rates the same name for 10L gas, not all gas.
- AstroAI S8 1500A 12V Lithium Jump Starter
AstroAI publishes two S8 manuals: the listing's gives 29.6 Wh and one USB output, AstroAI's site gives 37 Wh and two. Both set the same 75 percent rule.
- Schumacher SJ1332 Jump Starter and Power Station
Schumacher rates the SJ1332 at 1200 peak amps, 370 cranking amps and 150 PSI, with a 200W converter. The manual in the listing is headed SJ1330.
- GOOLOO GT4000 Arctic Jump Starter
GOOLOO GT4000 Arctic: 4000A peak, preheating claimed to -40, a -4F to 140F operating range, and listing and manual capacity figures that do not match.
- GOOLOO GT6000 Jump Starter (JS-271)
GOOLOO GT6000 guide: 6000 peak amps for 12V gas and up to 12.0L diesel, two capacity figures, 100W USB-C, the temperature limits and 18 or 30 months of warranty.
- NOCO Boost Pro GB150 3000A 12V Lithium Jump Starter
NOCO GB150 guide: rated 3000 A for 9.0L gas and 7.0L diesel, the guide that prints 4000 A, the voltmeter, 12V fast charge times, and two different box lists.
- NOCO Boost GB70 2000A 12V Lithium Jump Starter
NOCO GB70 guide: 2000 A for 8.0L gas and 6.0L diesel, the 12V in and out ports, recharge times by charger size, and the size and weight figures that disagree.
- NOCO Boost X GBX155 4250A 12V Lithium Jump Starter
NOCO GBX155 guide: 4250 A for 10L gas and 8.0L diesel, a 99 Wh pack, 2.7-hour recharge at 60 W against 16 hours at 10 W, the 60-second timeout and warranty.
- NOCO Boost X GBX55 1750A 12V Lithium Jump Starter
NOCO Boost X GBX55 specs: 1750A peak for up to 7.5L gas and 5.0L diesel, 46 Wh, 1.2 h recharge on 60W USB-C, 60-second timeout, 2.58 lb, 1-year warranty.
- NOCO Boost X GBX45 1250A 12V Lithium Jump Starter
NOCO Boost X GBX45 specs: 1250A peak for up to 6.5L gas and 4.0L diesel, 48-minute recharge on a 60W USB-C PD charger, 60-second timeout, 1-year warranty.
- DEWALT DXAELJ16 1600A Lithium Jump Starter with USB Power Bank
DEWALT's DXAELJ16 is a 1600A lithium jump starter for most 4, 6 and 8 cylinder engines. Its manual allows a second try after a 4-5 minute rest, then says stop.
- DEWALT DXAELJ18C 1800A Lithium Jump Starter with USB-C Power Bank
DEWALT's DXAELJ18C is an 1800A lithium jump starter with 30W USB-C in and out. It ships with a 12V car adapter and cable, not a wall plug, and charges at 32-104F.
- DEWALT DXAEPS14 2000 Peak Amp Jump Starter with Air Compressor and AC Outlets
DEWALT's DXAEPS14 pairs a 2000 peak amp sealed lead-acid jump box with a 120 PSI pump and two outlets sharing 500W. The manual asks for a 40-hour first charge.
- Schumacher Electric SL1690 2000A Peak Lithium Jump Starter and Power Pack
Schumacher SL1690 guide: 2000 peak amps for up to 9.0L gas or 7.0L diesel, a 37 Wh pack, three-start limit, override, temperature and storage rules, 2-year terms.