Ampper Side-Post Battery Disconnect Switch 12V/24V Knife-Blade Cut-Off Kit — Solid Brass, 200A

The Ampper side-post knife-blade battery disconnect switch is a compact master cut-off that isolates GM-style 3/8" side post batteries for safe, convenient power shut-off on cars, boats, RVs and ATVs.

Designed to sit on the side-post terminal, this two-position on/off switch uses a lift-out knife blade to break the circuit and stop parasitic drain when a vehicle or vessel is stored. Built from solid brass for corrosion resistance and supplied as a complete kit, it supports DC systems from 12V to 24V with heavy-duty current ratings appropriate for starting and accessory circuits.

How does this switch physically disconnect my battery?

The switch uses a knife-blade contact that lifts out of the terminal housing to create an open circuit. In the ON position the blade completes the connection; lift it and the circuit opens, cutting power to everything wired through that post.

• Knife-blade design: quick lift to interrupt power.
• Two-position operation: simple on/off control.
• Mounts on side post with supplied bolts, spacers and washers.

Will it fit my battery and electrical system?

It is sized for GM-style side post batteries and any battery with a 3/8" side-post terminal hole. The switch is recommended for installation on the negative side of the battery and supports both 12V and 24V DC systems.

• Compatible with 3/8" side post terminals only (GM-style).
• Rated for 200A continuous at DC systems and 600A momentary at 12V.
• Includes short and long bolts plus spacers to fit varying post heights.

How durable and safe is the Ampper switch for marine and vehicle use?

The switch body and contacts are made from solid brass to resist rust and corrosion, making it suitable for harsh environments like boats or exposed engine bays. Its simple mechanical action minimizes failure modes compared with more complex electronic isolators.

• Solid brass construction for corrosion resistance and longevity.
• Simple mechanical knife-blade reduces electrical failure points.
• Can be locked alongside other switches for added security.

What does the kit include and how easy is installation?

The Ampper kit arrives with the switch, two pairs of 3/8" side-post bolts (one short pair, one long pair), two spacers and two washers so you can size the connection to your battery post. Installation is straightforward with basic hand tools; mount the switch to the side post and secure with the supplied hardware.

• Complete hardware included for immediate installation.
• Recommended tools: wrench set, possibly a torque wrench for correct bolt tightness.
• Clear on/off operation—lift blade to disconnect power.

Who is this for: The Ampper side-post knife-blade battery disconnect is intended for vehicle, boat, RV and ATV owners who use GM-style side-post batteries and want a reliable, manual way to prevent battery drain, secure electrical systems during storage, or add a simple master switch for maintenance and theft deterrence. It suits DIY installers and professionals who need a compact, corrosion-resistant cut-off that handles starter-level currents without complicated wiring.