Best Jump Starter to Keep in the Trunk
The best jump starter to keep in the trunk for most drivers is the NOCO GB40 Boost Plus — a glovebox-sized pack rated by its maker for gas engines up to 6.0L, with the same UL-certified spark-proof electronics as NOCO's larger models. Owners of big V8s or diesels should size up to the NOCO GB70 Boost Pro (gas to 8.0L, diesel to 6.0L), and if you want a flat tire covered by the same box, the DEWALT JS400 adds a built-in 120-PSI compressor.
No prices or star ratings here per Amazon Associates policy — the buttons below open live, tagged Amazon searches for the current listings.
A trunk jump starter is bought for the one morning it matters, which is exactly why the marketing in this category is so loud: giant "peak amp" numbers sell packs. The problem is that peak amps is a brief burst figure that isn't standardized across brands — the honest way to size a unit is the manufacturer's own engine-displacement chart plus the pack's real energy capacity in Wh. The picks below are organized that way: by the engines they're actually rated to start, with every pick's watch-out stated plainly.
The fact worth keeping: A jump starter's advertised 'peak amp' number is a manufacturer marketing figure — a brief burst rating, not a sustained cranking-amp guarantee, and it is not standardized the same way across brands. What actually predicts whether a pack can start your engine is a combination of its real (not peak) output, its battery capacity in Wh, and your engine's displacement and cranking-amp requirement — cross-check independent reviews and the maker's own engine-size chart rather than comparing peak-amp numbers between brands as if they were equivalent.
The picks, by engine size and use
NOCO GB40 Boost Plus
1000A peak claim, 12V gas up to 6.0L / diesel up to 3.0L, spark-proof clamps, USB-C input/output
A pocketable unit sized for 4-cylinder to small V6 engines with the same UL-certified safety electronics as NOCO's larger models.
Best for: Sedan and compact-SUV owners wanting a glovebox-sized backup
Watch out: Undersized for larger V8/diesel engines — check your engine's actual displacement against the maker's stated range before buying, and note peak amps are not the same as sustained cranking amps.
Check price on AmazonNOCO GB70 Boost Pro
2000A peak claim, 12V gas up to 8.0L / diesel up to 6.0L, UltraSafe spark-proof clamps, USB-C 60W passthrough charging
NOCO publishes independently-verifiable UL 2743 safety certification on its Boost line rather than an unverifiable house number alone.
Best for: Buyers who want a name-brand unit with third-party safety certification, not just a marketing amp number
Watch out: The 2000A figure is a manufacturer peak (burst) rating, not sustained cranking amps — match the unit to your engine size by real-world reviews, not the headline number, and always follow your vehicle's manual for jump-starting procedure.
Check price on AmazonDEWALT Roadside Jump Starter (JS400)
1400A peak claim, built-in 120-PSI air compressor, 12V gas & diesel, dual USB out
Bundles a real air compressor with the jump pack so a flat tire and a dead battery are covered by one device.
Best for: Roadside-kit builders who want fewer separate gadgets
Watch out: Combo devices trade some jump-pack capacity and compressor speed for convenience — a dedicated compressor is faster, and 'peak amps' still is not the number that predicts a cold V8 start.
Check price on AmazonTOPDON 800A Peak Portable Jump Starter
800A peak claim, 12V gas up to 4.5L, LED flashlight w/ SOS mode, USB-C in/out
A low-cost entry unit sized honestly for smaller 4-cylinder engines rather than oversold for trucks.
Best for: Budget buyers with compact cars or motorcycles
Watch out: Not rated for larger engines — using an undersized unit on a V6/V8 can fail to start the car or overheat the pack; check the maker's engine-size chart first.
Check price on AmazonHow to choose
- Sedan or compact SUV (4-cyl to small V6): NOCO GB40 — compact, certified, sized honestly.
- Truck, large V8, or diesel: NOCO GB70 — match the maker's published engine range, not the amp headline.
- Want tire inflation in the same box: DEWALT JS400 compressor combo — accepting the combo trade-offs.
- Tight budget, small engine: TOPDON 800A — honestly rated for gas engines up to 4.5L, not oversold for trucks.
Capacity numbers confuse this category too: mAh only means something at a stated voltage, while Wh is the comparable unit across packs. We break that math down in mAh vs Wh on Jump Starters, and the full sizing logic lives in What Peak Amps Do I Need?
Frequently Asked Questions
For most sedans and compact SUVs, the NOCO GB40 Boost Plus is the strongest trunk-kit pick: it's glovebox-sized, rated by the maker for gas engines up to 6.0L, and carries UL-certified spark-proof safety electronics rather than just a marketing amp number. Larger V8 or diesel engines should step up to a unit whose published engine-size range actually covers them, like the NOCO GB70.
Peak amps is a manufacturer burst rating, not a standardized spec — so don't size by comparing peak numbers between brands. Use the maker's own engine-displacement chart (for example, NOCO rates the GB40 for gas engines up to 6.0L and the GB70 for gas up to 8.0L / diesel up to 6.0L) and cross-check independent reviews for real-world starts on your engine size.
Lithium packs self-discharge over time, and temperature extremes in a parked car accelerate it. Whatever unit you keep in the trunk, top it up periodically per the maker's instructions rather than assuming it holds the charge it left the box with — a dead jump pack is just trunk weight.
It covers two roadside problems — a dead battery and a soft tire — with one device, which is why combo units like the DEWALT JS400 exist. The trade-off is that combo devices give up some jump-pack capacity and compressor speed versus dedicated tools; a standalone compressor inflates faster.
These are consumer devices with spark-proof protections on the units we list, but the jump-start procedure itself varies by vehicle — always follow the sequence in your vehicle's owner's manual and the unit's instructions. This page covers sizing and buying, not procedure.