Updated October 15, 2026 · By Alex Mercer
Portable Jump Starters: Which Size Your Engine Needs, and the Best Picks
Portable Jump Starters: Which Size Your Engine Needs, and the Best Picks
A portable jump starter is sized by the engine it can start, not by the big peak amp number on the box. For most cars, the NOCO Boost GB40 is the safe pick, with by far the most owner ratings of these picks. For trucks and big diesels, the GOOLOO GP4000 covers up to 10.0L. If you also want a tire pump in the same box, the AstroAI S8 Air does both, and the DBPOWER 3000A is the budget choice.
The Short Version
Find your engine size (it is in the owner's manual or on the engine cover), then pick a jump starter whose maker rating covers it, with room to spare for cold mornings and diesel engines. Peak amps are not measured the same way by every brand, so a 4000A unit from one maker is not always twice as strong as a 2000A unit from another; the engine rating each maker publishes is the better guide. The picks below are based on manufacturer specs, current Amazon prices and what owners report in their reviews, not on our own testing.
Our Top Picks
| Product | Best for | Key spec | Rating | Price |
|---|---|---|---|---|
| NOCO Boost GB40 | Most cars and small SUVs | 1000A, gas to 6.0L, diesel to 3.0L | 4.6/5 ★★★★½ | $99.95 |
| GOOLOO GP4000 | Trucks, vans and big diesels | 4000A, gas and diesel to 10.0L | 4.6/5 ★★★★½ | $119.99 |
| AstroAI S8 Air | Jump starter plus tire pump | 3000A, gas to 9L, 150 PSI pump | 4.5/5 ★★★★½ | $89.99 |
| DBPOWER 3000A | Tight budgets | 3000A, gas to 8.0L, diesel to 6.0L | 4.5/5 ★★★★½ | $49.99 |
What Size Jump Starter Do You Need?
Match your engine to the maker's own rating. These are the ratings each maker lists:
| Jump starter | Gas engines | Diesel engines | Starts per charge |
|---|---|---|---|
| NOCO Boost GB40 | Up to 6.0L | Up to 3.0L | Up to 20 |
| DBPOWER 3000A | Up to 8.0L | Up to 6.0L | Up to 30 |
| AstroAI S8 Air | Up to 9L | Up to 6.5L | Up to 20 |
| GOOLOO GP4000 | Up to 10.0L | Up to 10.0L | Over 60 |
- Four and six cylinder cars (most engines from 1.5L to 3.5L): any pick here covers them. The GB40 is enough.
- V8 gas trucks and SUVs (5.0L to 6.2L): the GB40 is rated only to 6.0L, so skip it; the DBPOWER, AstroAI or GOOLOO cover these engines.
- Diesel pickups (6.6L and 6.7L): only the GOOLOO GP4000 is rated for them in this set.
- Cold climates: a cold battery needs more current to crank, so buy a size up from your engine.
What Owners Report
In the review summaries for the NOCO, GOOLOO and AstroAI, owners say the same things: a jump starter is much easier than jumper cables and a second car, and the units are small enough for a glove box or under a seat. The common complaint on those three listings is the same too: some units stop holding a charge or fail after months. Charge yours every few months, and check it before a long winter trip.
How to Use a Portable Jump Starter
1. Turn off the car and everything in it (lights, radio, heater).
2. Connect the red clamp to the battery's positive (+) terminal, then the black clamp to the negative (-) terminal or bare metal on the engine, as your unit's manual shows.
3. Wait for the unit to show it is ready. If the battery is too flat for it to detect, units like the GOOLOO GP4000 have a BOOST button that forces the start.
4. Start the car.
5. Remove the black clamp first, then the red, and let the engine run so the alternator can recharge the battery.
6. Recharge the jump starter when you get home.
Detailed Picks
1. NOCO Boost GB40: Best for Most Cars
NOCO rates the GB40 at 1000 amps for up to 20 starts per charge on gas engines up to 6.0L and diesels up to 3.0L. It has spark-proof and reverse polarity protection, a USB power bank for phones, a 100-lumen LED light with 7 modes, an IP65 rated housing, and weighs 2.5 lb. It recharges in about 3 hours.
What owners say: owners find it easy to use, easier than jumper cables, and like that it is compact enough to travel with. Battery life, durability and starting power get mixed feedback, with some reporting it would not recharge or failed within months.
Skip it if: your engine is a V8 truck or a diesel over 3.0L; it is rated below them.
2. GOOLOO GP4000: Best for Trucks and Diesels
GOOLOO rates the GP4000 at 4000 amps peak for gas and diesel engines up to 10.0L, and lists 12V cars, pickups, RVs, tractors, vans and boats. A BOOST button forces a start when the battery voltage is very low. It has two USB outputs (one fast charging) and a USB-C port that charges the unit and your phone; GOOLOO notes the wall charger is not included.
What owners say: owners find it easy to use and powerful, with cars starting on the first try, including one completely dead battery. Battery life and durability are mixed, and some note the missing charger.
Skip it if: you drive a small car; the GB40 or DBPOWER covers it for less.
3. AstroAI S8 Air: Best Jump Starter With a Tire Pump
A 3000A peak jump starter rated for gas engines up to 9L and diesels up to 6.5L, with up to 20 starts per charge, combined with a 150 PSI air compressor. The pump has 5 preset modes, stops automatically at the pressure you set, and AstroAI says it takes a tire from 32 to 36 PSI in about one minute. It is rated to start from -4 to 140°F.
What owners say: owners call it one of the best tools they have bought, praise the compact size and ease of use, including cold starts, and say the air pump works well. Battery life and durability are mixed, with some units failing within months.
Skip it if: you already carry a tire inflator; a dedicated jump starter saves space.
4. DBPOWER 3000A: Best Budget Pick
DBPOWER rates it at 3000A peak for gas engines up to 8.0L and diesels up to 6.0L, with up to 30 starts per charge. It has an 18000mAh battery, a smart USB port for phones, an LCD that shows the remaining charge, a compass and an LED light. The clamps have over current, short circuit, overload and over-voltage protection.
What owners say: one owner reports it started a car with a 6-year-old dead battery in seconds, using only 2% of the unit's charge (96% before, 94% after), and liked the light and phone charging.
Skip it if: you want spark-proof clamps like the NOCO; DBPOWER lists overload protections but not spark-proof connection.
How We Chose
We looked at portable lithium jump starters on Amazon with a current price and thousands of owner ratings, read each maker's engine rating, and compared the owner review summaries. See how we review products.
Building a roadside kit? Pair the jump starter with a car first aid kit.
Frequently Asked Questions
How many amps do I need to jump start a car?
Use the maker's engine rating rather than peak amps. A unit rated for gas engines up to 6.0L, like the NOCO GB40 at 1000A, covers most cars. V8 trucks and diesels need a unit rated for their engine size.
Can a jump starter damage my car?
Connecting the clamps backwards is the main risk. The GB40 lists spark-proof and reverse polarity protection. The DBPOWER lists over current, short circuit, overload, over-voltage and over-charge protection on its clamps. Whatever the unit, follow its manual for the clamp order.
How long does a jump starter hold its charge?
It slowly loses charge in storage, and owners of the NOCO, GOOLOO and AstroAI report some units that would not hold a charge. Recharge it every few months and before winter.
Can I charge my phone with it?
Yes. All four picks have a USB output that charges a phone.
The Verdict
Check your engine size, then buy the smallest unit rated for it: the NOCO GB40 for most cars, the GOOLOO GP4000 for diesel pickups and big trucks, the AstroAI S8 Air if you want a tire pump in the same box, or the DBPOWER 3000A on a budget.
Products Mentioned
1000A lithium jump starter rated for gas engines to 6.0L and diesels to 3.0L.
3000A jump starter with a 150 PSI air compressor; gas to 9L and diesel to 6.5L.
Budget 3000A jump starter rated for gas to 8.0L and diesel to 6.0L.