Cole Hersee 24059 12V Insulated Continuous Duty SPST Solenoid

In this review the Cole Hersee 24059 12V insulated continuous duty SPST solenoid is evaluated for installers and DIYers who need a straightforward heavy-current relay for a single 12V circuit. The bottom line: the solenoid is built for dependable On/Off operation with 85A normally open contacts, plated steel housing and solid copper studs, making it a sensible replacement where a single-circuit power switching device is required. It appeals to anyone who wants a simple, robust part that mirrors OEM form and function without unnecessary features.

Key Features

• 85A Normally Open Contacts: Provides high-current switching suitable for heavy accessories and starter circuits while remaining normally open when unenergized.
• SPST One Circuit: Simple Off - On operation reduces wiring complexity for single-load setups and minimizes potential failure points.
• Plated Steel Housing: Protects internal components from mechanical damage and offers a durable exterior for workshop or vehicle use.
• Copper Power Studs: 5/16-in -24 thread studs ensure reliable current transfer and come with hex nuts and lock washers for secure connections.
• Coil and Terminal Hardware: Coil ignition and ground terminals use 10-32 thread hardware and include nuts and lock washers for easy installation.
• Mounting Pattern: Bracket mounting holes placed on 2 13/64-in centers make it easy to mount to existing brackets or replace legacy units.

Who It's For

This solenoid is best for automotive technicians, boat owners, RV users and industrial maintenance staff who need a straightforward replacement or new install for a single 12V circuit rated around 85 amps. It suits situations where durability, simple operation and OEM-like fit are priorities, especially when the device must match an existing mounting pattern and terminal style.

Those who should look elsewhere include users needing multi-circuit switching, built-in overload protection or sealed PWM control for variable loads. If you require a waterproof or multi-position solenoid with advanced features, consider a different model designed for those specific needs.

Pros & Cons

Pros

• High-current 85A contacts deliver reliable switching for heavy loads without fuss.
• Solid construction with plated steel housing and copper studs gives a durable, serviceable feel.
• Included hex nuts and lock washers for both power studs and coil terminals make installation straightforward.
• Mounting hole spacing matches common brackets, easing replacement installations.

Cons

• Not sealed for aggressive marine exposure; consider a sealed unit if constant water immersion is expected.
• A minority of buyers reported missing hardware or defective units, so verify contents on receipt.

Specifications

Contact Rating	85A normally open
Configuration	SPST, one circuit Off - On
Power Studs	Copper 5/16-in -24 thread, hex nuts and lock washers included
Coil Terminals	Steel 10-32 thread, hex nuts and lock washers included
Housing	Plated steel
Mounting Holes	5/16-in x 19/32-in on 2 13/64-in centers (56.0mm)

Our Verdict

The Cole Hersee 24059 is a pragmatic choice for anyone needing a dependable single-circuit 12V solenoid with robust connections and an OEM-like fit. It delivers good value for routine automotive and light industrial switching where simplicity and reliability matter, provided you inspect the unit on arrival for completeness.

Frequently Asked Questions

Is this solenoid suitable for starter motor use?
It is rated 85A and is suitable for many starter or heavy accessory circuits, but confirm your starter draw and application requirements before use.

Does it include mounting and terminal hardware?
Yes; hex nuts and lock washers are included for the copper power studs and the 10-32 coil terminals, though some buyers reported occasional missing pieces on delivery.

Is the unit waterproof for marine use?
The housing is plated steel but not described as sealed for continuous immersion; choose a sealed marine-specific solenoid for permanent wet environments.