Send a part number, a photo, or a whole BOM — we supply it and stand behind it. Worldwide shipping to 80+ countries.

3G Electric
RFQ CartGet a QuoteSign inSign up
BATTERY DOCTOR Battery Disconnect Switch: Top Post Knife Blade, Top Post, Negative - Battery Disconnect Switches
BATTERY DOCTORBattery Disconnect Switches

BATTERY DOCTOR Battery Disconnect Switch: Top Post Knife Blade, Top Post, Negative

The BATTERY DOCTOR Battery Disconnect Switch is a top post knife blade switch with negative polarity and a maximum voltage of 12V. It features copper contacts and is identified by manufacturer part number 20138.

SKU 3G-OTH-497589

Brand
BATTERY DOCTOR
Item
Battery Disconnect Switch: Top Post Knife Blade, Top Post, Negative
Category
Battery Disconnect Switches
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineer
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

Technical Specifications

BATTERY DOCTOR
Manufacturer Part Number
20138
Type
Top Post, Negative, 12V
Polarity
Negative
Maximum Voltage
12V
Contact Material
Copper
View Full Spec Sheet

Technical Documents

No technical documents available for this product.
Request documentation →
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

BATTERY DOCTOR Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The BATTERY DOCTOR Battery Disconnect Switch is a top post knife blade switch with negative polarity and a maximum voltage of 12V. It features copper contacts and is identified by manufacturer part number 20138.

Frequently Asked Questions

What is a BATTERY DOCTOR Battery Disconnect Switch used for?

A BATTERY DOCTOR Battery Disconnect Switch isolates a 12V battery from its circuit to prevent parasitic drain, reduce fire risk during maintenance, and secure equipment. It is commonly used on vehicles, boats, RVs, and industrial machinery where a quick, reliable disconnect is needed.

What are the specifications of the BATTERY DOCTOR 20138 switch?

The BATTERY DOCTOR 20138 is a top post knife blade disconnect switch with negative polarity, rated for 12V maximum. It features copper contacts for efficient conductivity. The manufacturer part number is 20138, and it is designed for top post battery terminals.

Where to buy a BATTERY DOCTOR 20138 battery disconnect switch worldwide?

3G Electric supplies the BATTERY DOCTOR 20138 battery disconnect switch worldwide. We handle full logistics, customs clearance, and delivery to your location. Contact us to order this negative polarity, 12V top post knife blade switch with copper contacts.

How to install a BATTERY DOCTOR top post knife blade disconnect switch?

To install a BATTERY DOCTOR top post knife blade switch, first disconnect the battery negative cable. Clean the battery post, then slide the switch's copper contact over the post and tighten the nut. Connect the cable to the switch's other terminal. Always verify polarity and torque per manufacturer guidelines.

Used in

Common applications for BATTERY DOCTOR
Fleet maintenance — BATTERY DOCTOR 31200 Series circuit breakers for overcurrent protection in truck electrical systems
Automotive wiring harness repair — BATTERY DOCTOR GPT primary wires (20 AWG, 22 AWG) for replacing damaged low-voltage cables
Industrial control panels — BATTERY DOCTOR primary wires for internal wiring of 60 V control circuits
Marine battery systems — BATTERY DOCTOR circuit breakers for protecting DC circuits on boats
Off-road equipment — BATTERY DOCTOR 31200 Series breakers for resettable protection in ATVs and utility vehicles
Battery charger connections — BATTERY DOCTOR primary wires for extending charger leads in workshop environments

BATTERY DOCTOR Products

3G Electric supplies BATTERY DOCTOR battery disconnect switches. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

You might also need

Burners & Combustion →Pumps & Compressors →Spare Parts →All Products →

More from BATTERY DOCTOR

View all BATTERY DOCTOR parts →
BATTERY DOCTOR Battery Disconnect Switch: Side Post Rotary, Side Post, Negative, 12V, 500 A, Zinc (MPN 20310). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 500 A; Contact Material: Zinc; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Battery Disconnect Switch: Side Post Rotary, Side Post, Negative, 12V, 500 A, Zinc (MPN 20310). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 500 A; Contact Material: Zinc; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Battery Disconnect Switch: Emergency Cut-Off Switch, In-Line, DC, 12V, 1 Positions (MPN 20340). Key specifications — Polarity: DC; Maximum Voltage: 12V; Contact Material: Brass; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Battery Disconnect Switch: Emergency Cut-Off Switch, In-Line, DC, 12V, 1 Positions (MPN 20340). Key specifications — Polarity: DC; Maximum Voltage: 12V; Contact Material: Brass; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Battery Disconnect Switch: Top Post Knife Blade, Top Post, Negative, 12V (MPN 20148). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Battery Disconnect Switch: Top Post Knife Blade, Top Post, Negative, 12V (MPN 20148). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Master Disconnect Switch: In-Line Rotary, In-Line, Negative, 12V, 500 A Max Current (MPN 20243-7). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 5,000 A; Contact Material: Silver Plated Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Master Disconnect Switch: In-Line Rotary, In-Line, Negative, 12V, 500 A Max Current (MPN 20243-7). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 5,000 A; Contact Material: Silver Plated Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Starter Switch: In-Line Push Button, In-Line, Negative, 12V, 20 A Max Current, Copper (MPN 20302). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Starter Switch: In-Line Push Button, In-Line, Negative, 12V, 20 A Max Current, Copper (MPN 20302). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Battery Disconnect Switch: In-Line Rotary, In-Line, Negative, 12V, 250 A Max Current (MPN 20259). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 2,500 A; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Battery Disconnect Switch: In-Line Rotary, In-Line, Negative, 12V, 250 A Max Current (MPN 20259). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 2,500 A; Contact Material: Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Battery Disconnect Switch: Top Post Rotary, Top Post, Negative, 12V, 500 A, Zinc (MPN 20309). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 500 A; Contact Material: Zinc; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Battery Disconnect Switch: Top Post Rotary, Top Post, Negative, 12V, 500 A, Zinc (MPN 20309). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 500 A; Contact Material: Zinc; Brand: BATTERY DOCTOR.
BATTERY DOCTOR Master Disconnect Switch/Lockout: In-Line Rotary, In-Line, Negative, 12V, 5,000 A (MPN 20247-7). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 5,000 A; Contact Material: Silver Plated Copper; Brand: BATTERY DOCTOR.
BATTERY DOCTOR
BATTERY DOCTOR Master Disconnect Switch/Lockout: In-Line Rotary, In-Line, Negative, 12V, 5,000 A (MPN 20247-7). Key specifications — Polarity: Negative; Maximum Voltage: 12V; Maximum Surge Current: 5,000 A; Contact Material: Silver Plated Copper; Brand: BATTERY DOCTOR.