BooKoo A9 4000A 12V Jump Starter — 20000mAh Power Bank, 4000A Peak for Cars Boats Lawnmowers

The BOOKOO A9 combines high cranking power with a slim, lightweight design and multi-function outputs so you can jump-start vehicles, charge devices and light your way during roadside emergencies. Built to handle extreme temperatures and equipped with smart safety protections, the A9 is made for drivers, boaters and outdoor enthusiasts who want reliable power without bulky equipment.

How many times can the A9 jump a dead battery and what engines can it handle?

The A9 packs a 20000mAh battery capable of delivering repeated starts: it can jump-start a dead battery more than 50 times on a single charge under typical conditions. Its 4000A peak output is rated to start gasoline engines up to 12L and diesel engines up to 10L, covering most cars, trucks, boats and farm equipment.

• 20000mAh battery capacity for dozens of starts
• 4000A peak current for high-cranking needs
• Suitable for gasoline up to 12L, diesel up to 10L
• Works on cars, SUVs, trucks, tractors, boats, ATVs

What safety measures protect me and my vehicle when using the A9?

The A9 includes multiple built-in protections and smart jumper clamps to reduce user error and electrical risk. Visual indicators and audible beeps help you detect reversed polarity or other issues before current flows, and circuitry defends against short circuits, over-current, over-voltage, and more.

• Reverse polarity detection with warning lights and beeps
• Protection vs. over-current, over-voltage and short circuits
• Sparks and power-surge prevention circuitry
• Rugged clamps and insulated housings for safe handling

What else can the A9 do besides jump-start a vehicle?

The A9 doubles as a power bank and emergency lamp: two USB outputs (including QC 3.0) and a Type-C input let you recharge phones, tablets, GPS units and cameras quickly. A built-in 400-lumen LED offers steady, strobe and SOS modes for roadside visibility and night-time tasks.

• QC 3.0 USB port and standard USB for fast device charging
• 18W USB-C input for faster recharging of the unit itself
• 400LM 5W LED with steady, strobe and SOS modes (10+ hour run time)
• Compact footprint fits glove box or trunk; includes hard carrying case

Can the A9 handle bad weather and extreme temperatures?

Yes—the A9 is designed for outdoor use with an IP66-resistant rubber stopper to repel water, debris and splashes. It operates across a wide temperature range, so you can rely on it in rain, snow or hot climates when you need a dependable start.

• IP66 water-resistant sealing for wet conditions
• Operates from -4°F to 149°F (-20°C to 65°C)
• Rugged casing and storage case for protected transport

Who is this for: The BOOKOO A9 is ideal for motorists, boat owners, ranchers and outdoor hobbyists who want a lightweight, high-capacity jump starter that also charges devices and provides emergency lighting. It suits drivers who need a compact, reliable power solution for occasional jump-starts, long trips, or seasonal equipment like mowers and ATVs.

What’s included: A9 Jump Starter, smart jumper clamps, micro USB-A to USB-C cable, hard carrying case, user guide, lifetime technical support, 24-month warranty and round-the-clock after-sale service.