AstroAI S8 Air
#2 in Cars and SUVsFull review
A combined jump starter and tire inflator for small and mid-size cars. Good for drivers who want one compact roadside kit, not for trucks.
Amazon $59.99$59.99
3.3/5
For drivers of four- and six-cylinder cars who want a proven, compact pack to keep in the car. Owners of bigger engines should step up to a GBX55 or larger.
- 6 L gas, 3 L dieselEngines
- 24 WhBattery
- YesOverride
- 2.5 lbWeight
- 1 yearWarranty
Check price at Amazon$99.95
Price checked October 22, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Small enough for a glove box at under 2.5 lb
- Can force a jump on a completely dead battery with manual override
- Sealed against rain and dust
- Doubles as a phone power bank
Cons
- Slow to recharge: about 3 hours over a basic 10 W USB-C input
- Too small for V8 trucks: rated only to 6.0 L gas and 3.0 L diesel
- One-year warranty is short
How it scores
The rating comes from 4 measured or published factors, each scored 0-100 against fixed reference points for its engine size. How we rank explains each one.
Specifications
| Model number | GB40 |
|---|---|
| Starting | |
| Rated engines | 6 L gas, 3 L diesel |
| Peak amps (maker) | 1,000 A |
| Voltage | 12 V |
| Manual override | Yes |
| Lowest operating temperature | -22 °F |
| Battery and charging | |
| Chemistry | Lithium-ion |
| Capacity | 24 Wh |
| USB-C input | 10.5 W |
| Recharge time | 3 hours |
| USB outputs | USB 10 W |
| Build | |
| Flashlight | Yes |
| Air compressor | No |
| Water resistance | IP65 |
| Dimensions | 7.72 x 3.16 x 1.71 in |
| Weight | 2.5 lb |
| Warranty | 1 year |
| Released | 2015-12 |
Alternatives in this engine size
Fanttik Potent T10
#3 in Cars and SUVsFull review
A stylish, very compact pack for cars and small SUVs up to 7 liters that doubles as a phone charger. Pick it for portability, not for big trucks or deep cold.
Amazon $89.99$89.99
NOCO Boost X GBX45
#5 in Cars and SUVsFull review
For car and small-SUV owners who want a compact pack that refills fast from any USB-C charger. It costs a little more than the GB40 but recharges several times faster.
Amazon $124.95$124.95
Compare
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