Hanchu HESS-OF-E-3.5K 3.5kW 24V Off-Grid Solar Inverter
The Hanchu HESS-OF-E-3.5K is a 3.5kW single-phase off-grid solar inverter designed for residential backup power, small solar installations, farms, offices and other applications requiring reliable independent power.
It combines a pure sine-wave inverter, an integrated 100A MPPT solar charge controller and an AC battery charger in one compact unit. Its 3.5kW rated output and power factor of 1.0 allow the full inverter capacity to be used for compatible household and business loads.
Pure sine-wave output
The inverter produces stable pure sine-wave AC power suitable for most household appliances and sensitive electronic equipment.
Its rated output is 3.5kW, with surge capacity of up to 7,000VA for compatible loads requiring additional power during startup.
Integrated 100A MPPT solar controller
The built-in MPPT controller efficiently converts available solar energy into usable power while managing battery charging.
Solar specifications include:
- Maximum PV-array power: 4,000W
- Maximum PV open-circuit voltage: 500V DC
- MPPT operating range: 120–450V DC
- Maximum PV-input current: 15A
- Maximum solar-charging current: 100A
The final number of panels and string configuration must be calculated using the panels’ Voc, Vmp and current ratings.
24V battery system
The HESS-OF-E-3.5K operates with a 24V battery bank and supports CC/CV charging. Compatible lithium batteries must use appropriate inverter settings and, where required, approved communication or manual voltage configuration.
Battery settings include:
- Nominal battery voltage: 24V DC
- Floating-charge voltage: 27V DC
- Overcharge protection: 33V DC
- Maximum AC-charging current: 60A
- Maximum combined charging current: 100A
Battery-independent operation
The inverter can operate directly from sufficient solar input without a connected battery. Actual performance will depend on available sunlight, PV-array capacity and the connected load.
For stable backup operation during changing weather or at night, a correctly sized battery bank is recommended.
Flexible operating priorities
Multiple output-priority modes allow the system to be configured according to the customer’s energy requirements:
- UTL: Utility priority
- SOL: Solar priority
- SBU: Solar, battery and then utility
- SUB: Solar, utility and then battery
An equalisation function is available for compatible battery types to help optimise charging and battery performance. Equalisation must not be enabled for lithium batteries unless specifically permitted by the battery manufacturer.
Fast transfer time
The inverter automatically transfers between available power sources:
- Approximately 10ms for computer mode
- Approximately 20ms for household-appliance mode
This helps maintain power to compatible equipment during supply changes.
Efficiency and protection
The HESS-OF-E-3.5K provides peak PV-to-inverter efficiency of up to 96% and battery-to-inverter efficiency of up to 93%.
Integrated protection includes overload management, overcharge protection and system fault monitoring. A removable dust cover helps protect the inverter in dusty operating environments.
Typical applications
The inverter is suitable for:
- Residential load-shedding backup
- Small off-grid solar systems
- Flats and townhouses
- Farms and smallholdings
- Offices and small businesses
- Security systems, lighting and electronics
- Remote buildings and workshops
- Solar systems requiring a 24V battery bank
Key specifications
- Model: HESS-OF-E-3.5K
- Rated output: 3.5kW / 3.5kVA
- Phase: Single phase
- Output waveform: Pure sine wave
- Surge capacity: 7,000VA
- Battery voltage: 24V DC
- Maximum PV-array power: 4,000W
- Maximum PV open-circuit voltage: 500V DC
- MPPT range: 120–450V DC
- Maximum PV-input current: 15A
- Maximum solar-charging current: 100A
- Maximum AC-charging current: 60A
- Maximum combined charging current: 100A
- Communication: USB, RS232 and dry contact
- Net weight: 7kg