What does Error 04 mean on my Must inverter?

Error 04 means 'Battery voltage is too low.' This is a critical shutdown error that occurs when your batteries are fully depleted, often after extended use during load shedding or prolonged cloudy weather in Zimbabwe. You must recharge the batteries before the system will restart.

How is Error 64 different from Error 04?

Error 64 is a 'Low battery' warning. It's an early alert that your battery is getting dangerously low. Error 04 is the shutdown that follows if the situation is not resolved. Think of Error 64 as the warning light and Error 04 as the engine cutting out.

What causes Error 07 (Overload)?

Error 07, or 'Overload time out,' happens when you try to run too many high-power appliances at once (like a kettle, stove, or heater). The inverter shuts down to protect itself. To fix it, you must unplug high-demand appliances and restart the inverter.

What should I do if I see Error 56 (Battery connection is open)?

Error 56 is a critical wiring fault indicating the inverter cannot detect the battery. For your safety, do not attempt to fix this yourself. It could be a loose cable, blown fuse, or faulty isolator. You must call a professional solar installer immediately.

Home Solar System Troubleshooting System Troubleshooting Troubleshoot Batteries Troubleshooting Why Isn't My Solar Battery Charging? Common Inverter Error Codes & Battery Charging Guide

By Sona Brands

On September 24, 2025

19,699,888 Views

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Why Isn't My Solar Battery Charging? Your Guide to Inverter Error Codes

It's frustrating when your MUST Solar Inverter or SVolt Battery isn’t charging, especially during load shedding. This complete fault reference guide will help you decode common inverter error codes and restore reliable solar power in Zimbabwe without delay.

Common Inverter Error Codes & Battery Charging Guide

Decode your inverter's display to find the solution.

Before suspecting a major failure, check your inverter. As the brain of your solar system, it will display a specific fault code on its LCD screen when a problem occurs. Match the code to the common problems below to diagnose the issue.

Battery Related Faults

What it means: The battery is critically depleted, and the inverter has shut down to protect it from permanent damage. This is common during long periods of load shedding.
Solution: This is a state of overuse, not a system fault. You must allow the battery to recharge from solar or the grid before it will resume operation. If this happens frequently, your energy usage may be too high for your system's capacity.

What it means: This is the early warning that precedes Error 04. The inverter is alerting you that the battery charge is dangerously low.
Solution: Immediately reduce your home's energy consumption by switching off non-essential appliances to prevent a full shutdown.

What it means: The battery is overcharged, or the inverter's charging parameters are incorrect. The inverter has correctly stopped charging to prevent damage.
Solution: This is often caused by incorrect settings for your specific battery type (e.g., Lithium vs. AGM). A qualified technician must verify that the charging parameters match your battery's specifications.

Solar Panel (PV) Faults

What it means: The voltage from your solar panel array exceeds the inverter's limit, causing it to stop all solar charging.
Solution: This is a dangerous installation issue, usually meaning too many panels are connected in one string. Contact your original installer immediately to reconfigure the array safely.

What it means: These codes indicate a fault with the internal MPPT solar charge controller. The inverter cannot properly manage the current from the panels.
Solution: This is an internal hardware fault that requires a professional solar technician for repair.

Other Common Faults

What it means: Your home was drawing more power than the inverter could provide for too long. The inverter has shut down to protect itself.
Solution: Unplug high-power appliances like kettles, stoves, or heaters, then restart the inverter. If this occurs frequently, your inverter may be undersized for your needs.

What it means: A critical wiring fault. The inverter cannot detect the battery due to a loose terminal, blown fuse, or disconnected cable.
Solution: For your safety, do not attempt to fix this yourself. This requires urgent professional service. Call an installer immediately.

Frequently Asked Questions

During winter in Zimbabwe, shorter days and a lower sun angle mean solar panels receive significantly less energy. If a system isn't sized for these conditions, it may not fully recharge the batteries daily, leading to low voltage errors.

Even a new battery can't provide power it doesn't have. If persistent cloudy weather prevents your solar panels from generating enough electricity to recharge what you used overnight, the battery voltage will inevitably drop. This indicates an issue with insufficient generation (too few panels for the season) rather than a faulty battery.

The errors themselves are protective measures to *prevent* damage. However, repeatedly draining your batteries to this low level will reduce their overall lifespan. It's best to address the root cause—insufficient charging—to maintain the long-term health of your investment.

Get Expert Help & Restore Your Peace of Mind

Recurring inverter errors are a sign that your system needs a professional check-up. Our expert technicians can diagnose the root cause and provide a lasting solution. Contact Sona Solar Zimbabwe today for a system assessment.

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