Warning What does this mean?

Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.

Solis Inverter NO-Battery — Battery Not Detected, What to Do

NO-Battery means your Solis hybrid inverter cannot detect a battery. On a hybrid system the battery is essential — without it, energy storage, backup power, and several operating modes will not work. Check that the battery's breaker is on and the battery itself is awake; if everything looks connected and the alarm stays, your installer needs to investigate.

What should I do first?

Two quick questions — we'll point you to the right starting point.

Is this code still showing on your inverter's display?

What this code means

This message only appears on Solis hybrid inverters — the models designed to work with a battery for storing solar energy and providing backup power during outages. (If you have a plain grid-tied Solis with no battery, you will never see it.) Solis documents the alarm plainly: "Battery is not connected."

When the inverter starts up — and continuously during operation — it checks for the battery: its voltage, and for lithium batteries, communication with the battery's management system (BMS). If it finds nothing, it raises NO-Battery and the storage side of your system is effectively down. Depending on the model and settings, the inverter may still feed solar power to the grid, but backup power will not work, time-of-use shifting will not work, and on some models the inverter will not start properly at all.

The everyday causes are refreshingly mundane. The battery's breaker or isolator is switched off. The battery has gone into sleep or protection mode — lithium batteries do this after a deep discharge or long idle periods, and some need a wake-up action. Or the system is brand new and the battery simply hasn't been commissioned yet. The more technical causes — a blown battery fuse, a BMS communication failure, or a wiring problem between battery and inverter — all live firmly in installer territory, which is why the manual's own troubleshooting starts with checking the battery voltage and ends with contacting service.

What is this downtime costing you?

Rough estimate while your system isn't producing. Adjust the numbers to match your setup.

System size (kW) Peak sun hours / day Electricity rate ($/kWh)

–per day

–per week

–per 30 days

≈ – kWh of lost production per day.

Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.

Common causes

['The battery breaker or isolator is switched off — the single most common cause, and the easiest to check.', 'The battery is in sleep or protection mode after a deep discharge, long storage, or a BMS safety trip.', 'A blown battery fuse or tripped internal protection inside the battery unit.', "BMS communication failure — with lithium batteries, the inverter must 'talk' to the battery; if that link fails, it reports NO-Battery.", 'A wiring or connector issue between the battery and the inverter — installer diagnosis only.', 'A brand-new installation where the battery has not been commissioned or was left switched off.']

Safe steps to try

Work top to bottom, ticking off each step as you complete it. 0 of 1 done.

["Check the battery's own display or indicator LEDs — is it on, asleep, or showing an alarm of its own?", 'Make sure the battery breaker or isolator — the external switch, not anything inside a unit — is switched ON.', "On the inverter, check the information page for battery voltage — the manual's first check is whether the battery voltage reads within standards.", 'If your battery has a wake or start button described in its own manual, use it, then give the inverter a few minutes to detect the battery.', 'If the battery is on and connected but NO-Battery persists, stop there and call your installer — do not open anything or rewire.']

Is your inverter still under warranty?

Before paying for a repair, check — your installer may fix this free.

Brand Year installed

Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.

When to call an electrician

Call your installer if the battery is switched on and properly connected but the alarm will not clear, if the battery shows a fault of its own, or if you notice swelling, heat, or unusual smells coming from the battery unit. Battery wiring, BMS communication faults, and fuse issues are qualified-person work — and lithium batteries demand proper respect. Also call your installer if this is a brand-new system: commissioning, including battery detection and BMS pairing, is part of the installation job, not a homeowner task.

Frequently asked questions

My system is brand new — is NO-Battery normal?

It can be, if the battery has not been commissioned or was left switched off. But a new system should be fully commissioned by your installer — ask them to complete the setup rather than living with the alarm.

Can the inverter run on solar alone without the battery?

Some Solis hybrids can still feed solar power to the grid, but backup power and storage features will not work, and some models will not start properly. The system is not operating as designed until the battery is detected.

The battery breaker keeps tripping — what should I do?

Do not keep resetting it. A repeatedly tripping breaker is protecting you from a real problem — call your installer and leave it off.

Could a firmware update have caused NO-Battery?

Occasionally a BMS or inverter update can disrupt battery detection. If the alarm appeared right after an update, tell your installer — they can check BMS communication and firmware compatibility.

Need a professional?

This fault may need professional diagnosis. Contact a qualified solar electrician in your area.

Sources: meaning and troubleshooting verified against the manufacturer's documentation — Solis S6 Series Hybrid Inverter User Manual (V1.2, 06/2025), Table 7.1 — NO-Battery 'Battery is not connected' (solisinverters.com)