Coleman 3.5 Watt Solar Battery Trickle Charger with OBD-II Connector

In this review the Coleman 3.5 Watt Solar Battery Trickle Charger with OBD-II Connector is assessed for everyday vehicle maintenance use; it is aimed at drivers who want a simple, low-effort way to keep a 12V battery topped up between drives. The bottom line: this charger is best for owners of cars, SUVs, and light trucks who need a compact, durable solar trickle charger that connects three different ways and prevents battery discharge. The reviewer found it straightforward to use and particularly useful for preserving battery life on seasonal or infrequently driven vehicles.

Key Features

• Three connection options: The OBD-II connector, included 12V DC plug, and battery clamps give flexible ways to charge depending on vehicle and access, making it convenient for most modern cars.
• Fully automated trickle charging: Its automated operation makes it easy to leave the charger in place without constant monitoring, helping maintain the battery at a safe level.
• Built-in blocking diode: The diode prevents reverse discharge at night, so the panel will not drain the battery when sunlight is absent.
• Durable construction: The ABS plastic housing and shatterproof tempered glass on the panel stand up to outdoor use and handling.
• Compact 3.5W output: The small power output is sufficient to keep a 12V battery fresh over time without overcharging, which is ideal for maintenance charging rather than fast recovery.

Who It's For

The Coleman 3.5W trickle charger suits vehicle owners who store cars, motorcycles, SUVs, or trucks for periods between drives and want a low-maintenance method to prevent slow battery drain. It is ideal for weekend vehicles, seasonal equipment, or anyone who wants a compact solar option that plugs into the OBD-II port for safe, tool-free connection.

Those who need rapid jump-start power or fast battery recovery after a deep discharge should look elsewhere; this is a maintenance trickle charger, not a high-current starter or rapid charger. Also, very large batteries on commercial trucks or off-grid systems will require a charger with higher wattage and different specifications.

Pros & Cons

Pros

• Multiple connection methods make the charger adaptable to most modern vehicles and user preferences.
• Customers report it is easy to use and compact enough to store in a trunk or garage comfortably.
• The blocking diode and automated design protect against battery discharge and overcharging during normal use.
• Durable materials like ABS plastic and tempered glass improve longevity for outdoor placement.

Cons

• The 3.5W power level is intended for trickle charging only and will not quickly recover a deeply discharged battery.
• Effectiveness depends on available sunlight, so performance will vary in shaded or low-sun conditions.

Specifications

Product	Coleman 3.5 Watt Solar Trickle Charger with OBD-II Connector
Output power	3.5 Watt
Battery type	12V vehicle batteries
Connection options	OBD-II connector, 12V DC plug, battery clamps
Protection feature	Built-in blocking diode to prevent battery discharge
Materials	ABS plastic housing; shatterproof tempered glass panel
Use case	Trickle/maintenance charging for cars, SUVs, trucks

Our Verdict

The Coleman 3.5W Solar Trickle Charger is a practical, value-oriented choice for anyone who needs a low-maintenance way to maintain a 12V vehicle battery. Its multiple connection options, durable build, and automatic trickle charging make it a convenient tool for seasonal vehicles and infrequently used cars. Buyers looking for fast charging or jump-start capability should consider a higher-power device, but for routine battery care this charger offers good utility and reliability.

Frequently Asked Questions

Can this charger be left connected to the vehicle long-term?
Yes, the charger is designed for maintenance trickle charging and includes a blocking diode and automated control to prevent reverse discharge, making it suitable for extended connection.

Will it start a dead battery?
No, the 3.5W output is meant for trickle charging and maintaining charge; it will not provide the high current needed to start a deeply discharged battery.

Which vehicles are compatible with the OBD-II connection?
The OBD-II connector works with most modern vehicles equipped with an OBD-II port, providing a quick and safe way to connect without using clamps.