Top Post Battery Disconnect Switch, Battery Master Switch Isolator for 11-13 MM Battery Terminal Negative

Come back to a boat or a paddock truck after a month parked and the battery will tell you what kept drinking while you were away. This switch is the blunt answer: a knob-operated clamp for the negative top post, rated at 100 A on a DC 12 V system, that breaks the circuit entirely so nothing draws while the vehicle sits.

A knob, two positions, no electronics

Operation is entirely mechanical. Back the knob off and the circuit opens; run it down and you are connected again — on and off are the switch's only two states. Because the knob is the whole interface, there is nothing to program and nothing electronic in the path, and re-connection is the same twist in reverse.

The three limits printed on it

The supplier's spec line carries three boundaries worth respecting: the clamp suits an 11-13 mm cone, it belongs on the negative post only — the positive side is never offered — and the rating is 100 A on a 12 V DC system. A 24 V setup sits outside everything the supplier claims, and no claim gets extended for it here.

What isolation buys you

The supplier's stated purpose is threefold: isolate and secure the electrical system, eliminate any draw from the battery during lay-up, and disconnect safely when work needs doing. Cars, boats and RVs whose negative post is the standard top type are all named, general electrical equipment tacked on after them.

Key features

• Total cut-off: parked means parked — the supplier claims any battery draw is eliminated with the switch open.
• Knob-operated: the supplier calls it easy to install and simple to use, with the knob doing the switching.
• Clamp-on install: grips an 11-13 mm negative cone in place of the standard clamp; no panel to drill.
• Weather-hardy claim: solid made and resistant to rust and corrosion, in the supplier's words.
• Security by absence: a battery that is out of circuit is a vehicle that will not start for anyone.

Specifications

• Post accepted: 11-13 mm cone, top post, negative
• Electrical system: DC 12 V
• Rated current: 100 A
• Switch states: 2 — on and off
• Actuation: twist knob

Boundaries and blanks

• Negative post only. If your plan involves the positive terminal, this is not the device for it — the supplier scopes it to the negative side alone.
• The 100 A figure is tied to 12 V DC. Nothing here covers 24 V trucks or higher-voltage banks.
• The supplier ships this 100 A device without one line of installation or safety guidance; wiring judgement is yours or your auto electrician's.
• Housing material, overall dimensions and weight are all absent from the supplier text.
• Cutting the battery cuts everything it feeds, memory included — radio presets and dash clocks will reset. That is the nature of isolation, not a fault.

This is a clamp-on isolator: no drilling, fitted in the battery box itself, but strictly 12 V and strictly the negative post.

Returns, Refunds, and Replacements Products that are received faulty, damaged, or not as described are eligible for a return, refund, or replacement in accordance with the Australian Consumer Law (ACL). We are committed to ensuring all products meet the standards of quality and reliability expected by our customers. However, please note that we do not accept returns or provide refunds for change of mind. We encourage you to carefully consider your purchase to ensure it meets your needs and expectations.

Delivery Timeframe

Please note that we cannot guarantee the exact date of arrival, and the delivery timeframes (excluding weekends and public holidays) are as follows:

For customers in Victoria, approximately 7-10 working days; For customers in NSW, SA, ACT, and QLD, approximately 9-12 working days; For customers in WA, NT, and TAS, approximately 9-12 working days.