AstroAI S8 Ultra vs NOCO Boost GB40: Best Portable Jump Starter for 2026
Comparing raw power against everyday portability for 2026.
After putting both units through real-world stress tests, the NOCO Boost GB40 remains our top recommendation for the average driver due to its reliability and compact size. However, if you own a heavy-duty truck or a large diesel engine, the AstroAI S8 Ultra is the superior choice for its raw cranking power. We tested these units on a variety of vehicles to see which could handle deep-discharge scenarios and extreme temperatures.
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| NOCO Boost GB40 | AstroAI S8 Ultra | |
|---|---|---|
| Price | from US$99.95 | from US$72.18 |
| Rating | 9.2/10 | 10.0/10 |
| Peak Amps (A) | 1000 A | 4000 A |
| Battery Capacity (mAh) | 24000 mAh | 26800 mAh |
| Max Gas Engine | 6.0L | All |
| Max Diesel Engine | 3.0L | 12L |
| LED Flashlight | ✓ | ✓ |
How we test
We evaluated these jump starters by testing them on completely dead batteries in sub-freezing temperatures. We measured actual cranking success rates, the durability of the clamp construction, the accuracy of the LED indicators, and the real-world recharge time for the internal battery. We prioritized units that provided consistent voltage delivery without overheating during repeated attempts.
Frequently asked questions
Which jump starter is better for a standard sedan?
The NOCO Boost GB40 is ideal for standard sedans and SUVs up to 6.0L gas engines. It is smaller, easier to store in a glovebox, and offers proven safety features for daily drivers.
Can the NOCO Boost GB40 start a large diesel truck?
No, the GB40 is limited to 3.0L diesel engines. If you have a larger diesel engine, you must use the AstroAI S8 Ultra, which is rated for up to 12L diesel engines.
What is the main trade-off of the AstroAI S8 Ultra?
While the AstroAI S8 Ultra provides massive 4000 peak amps, its physical footprint is significantly larger than the NOCO, making it less convenient to keep in a small car console.