📋 Overview
The VT Series is a family of PWM (Pulse Width Modulation) solar charge controllers designed to regulate power flowing from your solar panels into your battery bank, protecting your batteries from overcharging while maximizing safe charge current. This guide covers three models: the VT40-30A (30A), VT40-40A (40A), and VT60-60A (60A).
Compared to our standard-line solar charge controllers, the VT Series is a step up in capability — it charges both lead-acid and lithium battery chemistries, accepts a much higher input voltage from your solar array, and adds a backlit display, extra USB charging ports, heavier-duty terminals, and improved heat dissipation for demanding installations. It's a great fit for anyone building a larger off-grid, cabin, RV, marine, or backup power system who wants flexibility for future battery upgrades.
⚠️ READ THIS FIRST — Connection & Disconnection Sequence Is Critical
This controller's internal circuitry — including its protection circuits — runs entirely off battery voltage. If the battery is not connected first, the controller has no power and cannot protect itself. Connecting a live solar panel to an unpowered controller can permanently damage it.
Connect in this order:
- Battery first. Connect the battery to the controller. Confirm the LCD display turns on before proceeding. If the display does not turn on, do not connect anything else — the battery may be too low (below ~10V) and must be charged first.
- Load second. Once the display is confirmed on, connect your load (lights, devices, etc.).
- Solar panel last. Connect the solar panel after the battery and load are connected.
Disconnect in reverse order:
- Disconnect the solar panel first.
- Disconnect the load second.
- Disconnect the battery last.
⭐ Key Features
- Dual Battery Chemistry Support — Charges both lead-acid batteries (Gel, Sealed, and Flooded) and lithium batteries (LiFePO4 and LiConMnNiO2), with the ability to enter user-defined charging parameters for both chemistries.
- Wide Voltage Compatibility — Supports 12V, 24V, 36V, and 48V battery banks. 12V, 24V, and 48V are automatically detected; 36V systems must be manually preset.
- High Input Voltage — Accepts solar array input up to 100V open-circuit voltage, allowing more panels to be wired in series.
- Backlit LCD Display — Clearly readable status and setting screens, even in low light.
- Quad USB Charging Output — 4× USB ports rated 5V/2A each (2 ports on each side of the housing) for charging phones, tablets, and other USB devices directly from the controller.
- Rugged Mounting — Metal mounting lugs on both sides support secure wall-mount or cabinet installation.
- Heavy-Duty Terminal Blocks — 6 large-aperture terminals with wider spacing accept thicker cables (6AWG for 30A/40A models, 4AWG for 60A model), supporting higher current wiring runs.
- Improved Heat Dissipation — Larger housing and a bigger heat sink keep the controller stable during extended full-load operation in high-temperature environments.
📊 Model Comparison & Specifications
All three models share the same core PWM control platform and feature set. The table below shows how they differ:
| Specification | VT40-30A | VT40-40A | VT60-60A |
|---|---|---|---|
| Rated Charge Current | 30A | 40A | 60A |
| Rated Discharge Current | 20A | 20A | 30A |
| Max PV Open Circuit Voltage | <100V | <100V | <100V |
| System Voltage | 12V/24V/48V (Auto) / 36V (Manual) | 12V/24V/48V (Auto) / 36V (Manual) | 12V/24V/48V (Auto) / 36V (Manual) |
| PV Max Input Power @ 12V | 390W | 520W | 780W |
| PV Max Input Power @ 24V | 780W | 1040W | 1560W |
| PV Max Input Power @ 36V | 1170W | 1560W | 2340W |
| PV Max Input Power @ 48V | 1560W | 2080W | 3120W |
| Charging Control Mode | PWM | PWM | PWM |
| Bluetooth (Optional) | Not included | Not included | Not included |
| Battery Types Supported | GEL / Sealed / Flooded / User-Defined Lead-Acid / LiFePO4 / LiConMnNiO2 / User-Defined Lithium | ||
| Float Charge Voltage | 13.8V / 27.6V / 41.4V / 55.2V (12V/24V/36V/48V) | ||
| Absorption Charge Voltage | 14.4V / 28.8V / 43.2V / 57.6V (12V/24V/36V/48V) | ||
| Equalization Charge Voltage | 14.6V / 29.2V / 43.8V / 58.4V (12V/24V/36V/48V) | ||
| Low Voltage Disconnect (LVD) | 10.7V / 21.4V / 32.1V / 42.8V (12V/24V/36V/48V) | ||
| Low Voltage Reconnect (LVR) | 12.6V / 25.2V / 37.8V / 50.4V (12V/24V/36V/48V) | ||
| USB Output | 4× USB, 5V/2A each (2 per side) | ||
| Display | Backlit LCD | ||
| Load Control Modes | 24-hour, Light Control, Reverse Light Control, Light + Dual Time-Period Control | ||
| Product Dimensions (L × W × H) | Approx. 200 × 106 × 47 mm (7.87 × 4.17 × 1.85 inches) | Approx. 200 × 106 × 47 mm (7.87 × 4.17 × 1.85 inches) | Approx. 200 × 132 × 62 mm (7.87 × 5.20 × 2.44 inches) |
| Mounting Hole Diameter | Ø5 mm (0.20 inches) | ||
⚠️ Important: The 36V system voltage is not automatically detected and must be manually set before use. Lithium battery types must also be manually configured — set the system voltage first, then select the corresponding lithium battery type.
🔋 Battery Type & Voltage Setup
The VT Series controller will automatically detect 12V, 24V, and 48V lead-acid battery banks. If you're running a 36V system, or if you're using a lithium battery bank at any voltage, you'll need to configure these settings manually using the front-panel MENU (+) and SET (–) buttons.
⚠️ Note: Download the manufacturer's User Manual (PDF) for detailed programming diagrams and sequence.
Setting the System Voltage
- From the home screen, press + to navigate to Screen 10 (System Voltage).
- Hold down + to enter the setting mode.
- Use + / – to select: Auto, 12V, 24V, 36V, or 48V.
- Hold down + to save your selection.
Setting the Battery Type
- From the home screen, press + to navigate to Screen 11 (Battery Type).
- Hold down + to enter the setting mode.
- Use + / – to select: User-Defined Lead-Acid, GEL, Sealed, Flooded, LiConMnNiO2 (4×3.7V or 3×3.7V cell groupings), LiFePO4 (5×3.2V or 4×3.2V cell groupings), or User-Defined Lithium.
- Hold down + to save your selection.
📝 Note: If you are using a lithium battery, set the system voltage first, then select the matching lithium battery type. Setting these out of order can cause incorrect charging parameters.
🔌 Wiring Overview
The VT Series is a positive-electrode (common positive) controller. The positive terminals of the solar array, battery, and load can all share a common ground if needed. Basic system wiring includes:
- PV Array — connects through a breaker to the controller's solar input terminals
- Battery — connects directly to the controller's battery terminals (fuse recommended)
- Load — connects to the controller's load output terminals (fuse recommended)
⚠️ Important: If your system includes an inverter or other high-inrush-current load, connect the inverter directly to the battery terminals — not to the controller's load output.
📡 Load Working Modes
The controller's load output (used for lights or DC accessories, not your main battery bank) can be configured to one of several working modes:
| Mode | Description |
|---|---|
| 24-Hour Work | Load stays on continuously |
| Light Control Mode | Load turns on automatically after dark and stays on until sunrise |
| Reverse Light Control | Load works during the day and turns off at night |
| Light + Dual Time-Period Control | Load turns on after dark for a first user-set period, then again for a second user-set period before dawn |
🛠️ Troubleshooting
| Error Code | Cause | Solution |
|---|---|---|
| Ex1 | Battery undervoltage | Low-voltage disconnect triggered, load turns off. Check battery health and charge level. |
| Ex2 | Battery overvoltage | Overvoltage protection triggered, load turns off and charging stops. Check for wiring or battery configuration errors. |
| Ex3 | Overload protection | Check the load wiring, or reduce the connected load. |
| Ex5 | Overheating protection | Internal overheat protection has stopped charging. Charging resumes automatically once the unit cools. |
| Ex6 | Overcurrent protection | Charging current exceeded rated current. The controller will automatically recover within 2 minutes. |
💡 Tips for Best Results
- Always follow the connection sequence — Battery first, solar panel second, load last. This protects the controller's internal circuitry.
- Set lithium parameters before connecting solar — If using a lithium battery, set the system voltage and battery type before powering up the array, to avoid incorrect charge voltages.
- Match your terminal wire gauge to your current draw — The VT Series' large-aperture terminals accept thicker cable, which reduces voltage drop on high-current runs.
- Give it room to breathe — Mount the controller in a location with good airflow around the heat sink fins, especially in hot climates or at high sustained loads.
- Don't run inverters off the load terminal — High-inrush loads like inverters should connect directly to the battery, not through the controller's load output.
- Use the app for detailed monitoring — On Bluetooth-equipped models (VT40-40A, VT60-60A), the companion app gives you an easy way to review charging history and adjust parameters without using the front-panel buttons.
🏪 Where to Buy
Buy the VT Series PWM Solar Charge Controllers at Envistia Mall.
- 📦 Fast US Shipping
- 🔄 Hassle-Free Returns
- 📧 Responsive Customer Support
📚 Resources & Downloads
- User Manual (PDF): VT Series Solar Charge Controller User Manual
This guide is provided by Envistia Mall for educational and technical reference purposes. The manufacturer and Envistia LLC (dba Envistia Mall) are not responsible for any damages or losses resulting from the use of this product. Always follow proper electrical safety practices when working with electronic components. Specifications are based on manufacturer data and are subject to change without notice.