Can this jump start a V8 engine?

The J309 is rated for vehicles up to V6 engines with 300 instant amps and 600 peak amps. A V8 may require more cranking power, especially in cold weather. Stanley offers higher-amperage models for larger engines.

How often does the unit need to be recharged?

Stanley recommends recharging every 30 days when not in use to maintain the internal battery. An integrated charging cube is built in — just plug in a standard household extension cord.

Can I use the USB ports while jump starting a vehicle?

The USB ports and 12V outlet function independently for device charging and power needs. However, during a jump start attempt, focus the unit's power on starting the vehicle rather than running other loads simultaneously.

Specifications

Brand: Stanley
Part #: J309
SKU: VECJ309

StanleySKU: VECJ309

Stanley 300 Amp Jump Starter

Name: Stanley 300 Amp Jump Starter
Brand: Stanley
SKU: VECJ309
Price: 87.95 USD
Availability: InStock

$87.95

Usually ships the next business day

Stanley J309 portable jump starter delivers 300 instant amps and 600 peak amps with built-in LED light, USB ports, and 12V outlet.

Key Features

300 instant starting amps and 600 peak amps for 4-cylinder and V6 engines.
High-powered LED light rotates 270 degrees for visibility in the dark.
Three USB ports for charging phones, tablets, and other devices.
12V DC outlet powers accessories and small electronics.
Reverse polarity alarm alerts you to incorrect clamp connections.
Integrated charging cube recharges from any standard household outlet.

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About this part

Product Details

Dead batteries do not wait for convenient times, which is why keeping a portable jump starter in the trunk makes sense. Stanley's J309 delivers 300 instant starting amps and 600 peak amps — enough to start most 4-cylinder and V6 engines without needing another vehicle or a set of jumper cables.

Beyond jump starting, the J309 works as a portable power station. It has three USB ports for charging phones and tablets, a 12V DC outlet for accessories, and a high-powered LED light that rotates 270 degrees for working in the dark. The all-metal battery clamps are powder-coated and connect securely to battery terminals, and a reverse polarity alarm warns you if the clamps are connected incorrectly.

An integrated charging cube lets you recharge the unit using a standard household extension cord. Stanley recommends charging every 30 days when the unit is not in use to keep the internal battery healthy. At 10 lbs, it is heavier than lithium-based jump starters but carries more sustained cranking power for larger engines. If your vehicle is a V8, you may want to look at a higher-amperage unit.