1stesss CM Series Off-Grid Solar Inverter with MPPT Charging Pure Sine Wave and Optional WiFi Monitoring

Explore 1stesss CM Series 1.5–3.5kW off-grid solar inverters with MPPT charging, pure sine wave output and optional WiFi for home solar backup.

The 1stesss CM Series is a compact off-grid solar inverter range combining a pure sine wave inverter, an MPPT solar charge controller, and an AC battery charger. Available in 1.5kW, 2.5kW, and 3.5kW rated-output models, it supports residential solar power systems and small-business backup applications with 220/230V AC output.

Designed for use with solar panels, a compatible battery bank, and utility input, the CM Series helps installers configure an essential-load power supply around local project requirements. Optional WiFi monitoring adds remote visibility for supported installations.

For solar equipment distributors, importers, and installation contractors, 1stesss offers multiple power and battery-voltage options within one product series.

The integrated MPPT controller manages solar battery charging, with maximum PV array capacities ranging from 2000W to 4000W according to the selected model.

This integrated configuration simplifies equipment selection for compact solar-plus-battery installations. PV string design must account for the inverter's voltage and current limits as well as module specifications and local temperature conditions.

The 500V PV open-circuit rating is a maximum limit, not a recommended string operating target.

The CM Series supplies pure sine wave AC power for appropriately sized loads such as lighting, routers, televisions, fans, and office electronics.

Refrigerators and other motor-driven appliances require additional startup-load assessment. For backup system sizing, installers should use the selected model's battery-mode output rating and check simultaneous demand.

For example, the 3.5kW model is specified for 3kW output in battery mode.

The series supports multiple priority modes identified as UTL, SOL, SBU, and SUB. These settings allow installers to configure power-source priorities according to the installation requirements and operating manual.

Solar charging and utility charging are integrated into the same unit. The maximum combined charging current is 100A; the solar and AC charging limits should not be added together.

Actual charging settings must match the connected battery's permitted voltage and current.

CM Series S models support lithium battery activation triggered by PV input. This feature is distinct from battery communication.

The series does not support lithium battery BMS communication. Battery compatibility therefore requires confirmation of operating voltage, charging parameters, discharge capability, and protection behavior with the battery supplier.

For lithium battery installations, equalization settings must also be checked against the battery manufacturer's requirements.

An optional WiFi accessory supports monitoring through compatible app and web interfaces. This provides an additional way to review system operation in residential solar backup installations.

Buyers should confirm the required WiFi accessory and monitoring platform when placing an order.

With a compact enclosure and detachable dust cover, the 1stesss CM Series suits indoor utility areas where space and maintenance access matter.

Its IP21 rating requires a suitable dry indoor location. Installers should provide ventilation clearance and access for inspection and cleaning.

• Residential solar backup: Supply selected household circuits with a correctly sized solar and battery system.
• Small-shop backup power: Support lighting, payment equipment, routers, and other essential business loads.
• Off-grid solar installations: Combine PV generation and compatible battery storage for sites requiring an independent power supply.
• Solar distribution projects: Select from 12V and 24V inverter models according to customer load and battery requirements.

It can be considered for compatible lithium battery configurations after checking voltage, charging settings, discharge current, and BMS requirements. S models support PV-triggered lithium battery activation, but the series does not support lithium battery communication.

No. The supplied specifications state that parallel operation is not supported.

The CM Series is rated IP21 and should be installed in a suitable dry indoor location.

The datasheet lists 3500W rated output and 3000W battery-mode output. Use the battery-mode rating when assessing backup loads.

WiFi monitoring is optional. Specify the required accessory when requesting a quotation.