Can I use this solar controller to charge a standard 12V Lead-Acid battery?

No, you cannot use this specific controller for a 12V Lead-Acid battery. This OHS-3S model is strictly calibrated with specific voltage cut-offs designed exclusively for 11.1V (3S) Lithium-ion battery packs to prevent dangerous overcharging.

Why is a dual MOSFET circuit better than a standard diode controller?

A dual MOSFET circuit is better because it significantly reduces electrical resistance, cutting voltage loss by up to 50% compared to traditional diodes. This means more of the solar energy actually reaches your battery, and the controller generates much less heat during operation.

What is the correct wiring sequence for this solar controller?

The correct wiring sequence is to always connect your 11.1V Lithium-ion battery to the controller first. Once the controller powers on and recognizes the battery, you can then connect the solar panel, followed finally by your DC load (e.g., LED lights).

What happens to my timer settings if the battery completely dies during a cloudy week?

Your timer settings will remain perfectly intact even if the battery completely dies. The controller features a built-in power-off memory chip that saves all your system modes and parameters, so it will resume normal operation automatically once the sun recharges the battery.

Can I get help sizing my solar panel for this controller at your Hong Kong store?

Yes, you can bring your project details to Sun Cheong Computer Co. Ltd. (新昌電腦有限公司) in Sham Shui Po for expert advice. Our technical staff can help you calculate your load requirements and select a solar panel that safely matches the 3A limit of this controller.

11.1V 3A PWM Solar Charge Controller

Name: 11.1V 3A PWM Solar Charge Controller | 3S Li-ion Regulator
Brand: Sun Cheong Computer Company Limited
SKU: 21TS000903
Price: 88.0 HKD
Availability: InStock

Short Product Description

The 11.1V 3A PWM Solar Charge Controller (OHS-3S) is a smart power regulator specifically designed for 3S (11.1V) Lithium-ion battery solar setups. Featuring an ultra-efficient dual MOSFET circuit, power-off memory, and three automated lighting control modes, it safely manages solar harvesting for DIY off-grid lighting and STEM projects. Available for instant pickup at Sun Cheong Computer Co. Ltd.(新昌電腦有限公司) in Sham Shui Po, our technical staff can provide expert wiring advice to ensure your custom solar panels and lithium batteries operate safely and efficiently.

Key Features

3S Li-ion Optimized: Specifically calibrated to safely charge and discharge 11.1V (3-cell) Lithium-ion battery packs.
Dual MOSFET Efficiency: Reduces voltage loss by 50% and increases PWM charging efficiency by 3-6% compared to standard diode circuits.
Power-Off Memory: An internal chip saves all system modes and control parameters, preventing data loss during complete power failures.
3 Automated Modes: Choose between Normally Open (Always ON), Pure Light Control (Dusk to Dawn), and Light Control + Timer modes.
Comprehensive Safety: Built-in protection against overcharging, over-discharging, short circuits, overloads, and reverse polarity connections.
Intuitive LED Indicators: Front-facing LED lights provide instant, easy-to-read visual feedback on your battery's current charge status.

Full Product Description

Smart Solar Management for 3S Li-ion Batteries

This 11.1V Solar Controller utilizes an advanced PIC microcontroller to deliver highly stable, interference-free charging specifically for 3-cell (3S) Lithium-ion battery packs. By employing a high-efficiency PWM (Pulse Width Modulation) charging mode, it significantly extends your battery's lifespan while maximizing the energy harvested from your solar panels. It features comprehensive electronic protections—including overcharge, over-discharge, and reverse polarity protection—making it incredibly safe for DIY off-grid power systems.

Dual MOSFET Circuit for Maximum Efficiency

The internal charging circuit features a dual MOSFET series design that cuts voltage loss by nearly 50% compared to traditional diode-based solar controllers. This ultra-low resistance architecture ensures that more solar energy reaches your battery, boosting overall charging efficiency by 3% to 6% and keeping the module cool during continuous 3A operation. The controller also utilizes discharge rate correction, which dynamically adjusts the termination voltage based on how fast the battery is discharging, perfectly matching the inherent characteristics of lithium-ion cells.

Automated Lighting Control with Power-Off Memory

You can easily automate your DIY solar street lights using the controller's three selectable working modes: Normally Open, Pure Light Control, and Light Control with Timer. Furthermore, the built-in power-off memory chip automatically saves all your parameter settings. This ensures your system recovers seamlessly and maintains its timer configurations after a complete battery drain, without requiring any manual reprogramming.

Pro Tip from Our Technicians

When wiring this PWM Solar Regulator, our Sham Shui Po technical team strictly advises connecting your 11.1V Li-ion battery to the controller first, before connecting the solar panel. This sequence allows the MCU chip to correctly recognize the battery voltage and initialize the protection circuits. Always use insulated tools and install an inline fuse between the battery and the controller to prevent catastrophic short circuits.

Technical Specifications

Model: OHS-3S-11.1V3A
Product Type: PWM Solar Charge Controller
Supported Battery Type: 3S Lithium-ion (Li-ion)
Rated Voltage: 11.1V DC
Rated Current: 3A
Charging Technology: PWM (Pulse Width Modulation) with Dual MOSFET
Control Chip: Advanced PIC Microcontroller (MCU)
Working Modes: Normally Open, Pure Light Control, Light Control + Timer
Dimensions: 53.4mm x 68.6mm x 22mm
Package Contents: 1x Solar Charge Controller, 1x Instruction Manual

Delivery Options

Local delivery within Hong Kong and in-store pickup.
Free shipping for orders of HK$400 or above; HK$35 shipping fee for orders below HK$400.
Shipped by SF Express, usually dispatched the same day for orders confirmed before 6:00 PM (Mon–Sat).
Estimated delivery time: 1–3 business days after dispatch (Hong Kong).
In-store pickup details (location and time) will be confirmed by email or phone message.
Delivery times are estimates and may be affected by weather or unforeseen circumstances.

FAQ Section

Can I use this solar controller to charge a standard 12V Lead-Acid battery?No, you cannot use this specific controller for a 12V Lead-Acid battery. This OHS-3S model is strictly calibrated with specific voltage cut-offs designed exclusively for 11.1V (3S) Lithium-ion battery packs to prevent dangerous overcharging.
Why is a dual MOSFET circuit better than a standard diode controller?A dual MOSFET circuit is better because it significantly reduces electrical resistance, cutting voltage loss by up to 50% compared to traditional diodes. This means more of the solar energy actually reaches your battery, and the controller generates much less heat during operation.
What is the correct wiring sequence for this solar controller?The correct wiring sequence is to always connect your 11.1V Lithium-ion battery to the controller first. Once the controller powers on and recognizes the battery, you can then connect the solar panel, followed finally by your DC load (e.g., LED lights).
What happens to my timer settings if the battery completely dies during a cloudy week?Your timer settings will remain perfectly intact even if the battery completely dies. The controller features a built-in power-off memory chip that saves all your system modes and parameters, so it will resume normal operation automatically once the sun recharges the battery.
Can I get help sizing my solar panel for this controller at your Hong Kong store?Yes, you can bring your project details to Sun Cheong Computer Co. Ltd. (新昌電腦有限公司) in Sham Shui Po for expert advice. Our technical staff can help you calculate your load requirements and select a solar panel that safely matches the 3A limit of this controller.

Target Users / Applications

Village House Owners: Automating rooftop or garden LED solar lights using the "Pure Light Control" mode to turn on at dusk and off at dawn.
Off-Grid Campers: Building portable, lightweight 11.1V lithium-ion solar generator boxes for charging small electronics during camping trips.
STEM Robotics Students: Managing solar power harvesting for autonomous outdoor weather stations or remote environmental sensors.