1stess Solar Backup for Kenyan Homes: A CM Series Inverter Project

1stess Solar Backup for Kenyan Homes: A CM Series Inverter Project

Project Overview

Customer Requirements

Daniel was seeking a compact residential solar inverter for customers who needed backup power for lighting, televisions, internet routers, fans, and selected refrigeration loads. His installation team wanted an integrated solution combining a pure sine wave inverter, an MPPT solar charge controller, and utility charging.

During the customer visit, Penny reviewed the intended applications, battery configuration, installation conditions, and purchasing requirements. The discussion focused on selecting an appropriate inverter for essential loads and making installation requirements clear before shipment.

The proposed solution was the 1stess CM3500-24S, a 24V off-grid inverter designed for solar and battery energy storage applications.

Product Selection and Technical Details

The proposed configuration used the following specifications from the supplied CM Series datasheet:

The CM3500-24S also supports PV-triggered lithium battery activation. This function is separate from BMS communication and does not mean the inverter exchanges battery data through CAN or RS485.

Challenge 1: Matching the Inverter to Actual Backup Loads

The initial load list included household essentials alongside high-power appliances. Sizing the installation using only the model’s 3.5kW rating could have created unrealistic expectations because the datasheet specifies 3kW output in battery mode.

Penny coordinated a load review with the technical team. The proposed installation separated essential backup circuits from electric cooking appliances, water heaters, and other demanding loads. Refrigeration startup requirements were also included in the review.

This gave the installer a clear load plan and helped explain to end users which appliances could operate together during an outage.

Challenge 2: Configuring a Compatible Lithium Battery

The customer wanted to pair the inverter with a lithium battery energy storage system. However, the CM Series does not support lithium battery communication.

The proposed solution was to select a compatible 24V-class battery and confirm its operating voltage, charge settings, discharge capability, and BMS protection requirements with the battery supplier. Charging current would be limited according to the battery’s permitted value, rather than automatically using the inverter’s 100A maximum.

The commissioning instructions also required checking equalization settings and disabling equalization where required by the lithium battery manufacturer.

Challenge 3: Designing the Solar Array Correctly

The customer’s installers needed a repeatable PV configuration for residential installations.

The technical review checked module specifications, series-string voltage, and input current against the inverter’s limits. The 500V maximum PV open-circuit voltage was treated as a limit, with temperature effects considered when checking string voltage.

The team also verified that the proposed array respected the 15A maximum solar input current and 4000W maximum PV array power. This helped avoid selecting a solar panel arrangement based on wattage alone.

Challenge 4: Managing Dust and Installation Conditions

Some proposed sites included utility rooms near dusty outdoor areas.

Because the inverter is IP21, the installation plan specified a dry indoor location with appropriate ventilation and access for maintenance. The detachable dust cover was included in maintenance guidance, together with periodic inspection and cleaning.

Penny emphasized the need to maintain airflow and avoid exposure to rain, splashing water, or excessive dust accumulation.

Shipment and Delivery Details

For this illustrative order, the shipment consisted of 50 CM3500-24S inverters, with optional WiFi modules packed and identified separately.

The datasheet lists a packaged size of 402 * 368 * 174mm and a gross weight of 5.25kg per inverter. For 50 units, the inverter cartons therefore represented approximately 262.5kg before additional pallets, accessories, or export protection. Final shipping weight and volume would be confirmed after packing.

The example delivery process included:

• Checking model numbers, quantities, serial numbers, and accessories against the order.
• Completing agreed pre-shipment functional checks and retaining inspection records.
• Protecting each inverter with its individual carton and internal cushioning.
• Preparing the commercial invoice, packing list, and applicable shipping documents.
• Shipping by sea from Shenzhen to Mombasa, followed by local delivery to Nairobi.

Penny coordinated packing confirmation, document review, and shipment updates with the customer and freight forwarder. Transit time and final delivery dates would be confirmed against the actual booking.

Installation Support and Project Handover

The proposed rollout began with a small group of pilot installations before wider deployment. Technical support covered PV and battery connections, grounding, output priority settings, charging parameters, and optional WiFi setup.

The handover checklist required installers to confirm essential-load operation, utility-to-battery transfer, charging behavior, and startup performance under the intended configuration. Any pilot issues would be addressed before applying the same setup to additional sites.

Project Value

This example shows how 1stess can support a solar distributor or installation contractor beyond product supply. Load assessment, battery compatibility review, PV configuration, export coordination, and commissioning guidance all contribute to a more clearly defined residential solar backup solution.

For buyers sourcing an off-grid solar inverter, MPPT inverter, pure sine wave inverter, or residential battery backup system, the CM Series provides multiple power options for projects with different load and battery requirements.

Planning a Solar Inverter Order?

Share your target market, essential-load list, PV module specifications, battery details, and order quantity with 1stess. Our team can help review the configuration and prepare a supply proposal for your residential solar energy storage or small-business backup power project.