(checked 2026-10-10)Only 99 ratings on this listing, whose title includes an EVA storage case. No larger single-unit Amazon.com listing for the GT4000S was found.
CNN's best jump starter overall. It had some of the strongest output in CNN's tests, plus a big screen and instructions printed on the back. It's chunky, has no hard case, and its 4,000-amp rating is marketing; CNN measured about 3,500 W.
Top complaints
- Bulky
At 9 x 4 x 2 inches, CNN calls it a bit chunky, and it doesn't come with a hard-shell case.
Source: CNN Underscored - Awkwardly placed flashlight
CNN says the flashlight is on the opposite side from the cable port.
Source: CNN Underscored - Peak-amp claim is inflated
Gooloo advertises 4,000 peak amps. CNN measured roughly 360-480 A, and an AAA engineer told CNN that peak amps are more a marketing term than reality.
Source: CNN Underscored
What owners love
- Among the strongest outputs CNN measured
About 3,500 W in each load trial (360 A at 9.5 V, 480 A at 7.5 V), which CNN says is enough for most engines unless you drive a big diesel truck.
Source: CNN Underscored - Easiest to understand
It has a large screen with the exact battery percentage and a 'ready' signal, three-step instructions and a troubleshooting chart on the back, a clearly labelled boost button, and an X plus a beep if you reverse the clamps (CNN).
Source: CNN Underscored - Long leads and fast recharging
The 11- and 10-inch leads are longer than on some rivals. A 100 W USB-C port recharges it quickly, and it comes with a 100 W charger and several cables (CNN).
Source: CNN Underscored
- You drive a big diesel truck
- You want glove-box size
- You want a hard case
- First-timers who want instructions on the unit
- Most cars, SUVs and pickups (gas)
- Using it as a USB-C power bank
Scores (tap for why)
What experts say
- CNN Underscored: Best jump starter (published 2026-04-30): beginner-friendly, with output among the best tested. Cons are its chunky size, no hard case and a badly placed flashlight.