Ventilation requirements and design guidelines for battery installations
Before starting an installation, installers are required to document and share a detailed specification drawing (enlinjeschema / planritning) with KanEL for review. Failure to do so may result in KanEL not being able to support with issues resulting from poor ventilation.
The installer is responsible for ensuring that ventilation is sufficient for the system to operate according to specification. If in any doubt, consult an external ventilation expert.
NOTE: If the batteries and inverter do not fulfil the requirements below, they may not be operational with KanFLEX.
Mandatory temperature and airflow requirements
These are hard requirements. The system must be designed to meet all of them before commissioning.
Battery temperatures must be maintained between 15–25°C while resting
Maximum temperature difference across all battery units: 5°C
Time for batteries to reach 45°C at full power: minimum 1.5 hours
Inverters require continuous airflow at all times
Maximum air outlet temperature from inverters: 60°C
Cooling approaches
There are two general approaches to meeting cooling requirements. The right choice depends on whether the inverter and batteries are in the same room or separate rooms.
Air conditioner / heat pump — suitable primarily when inverter and batteries are in separate rooms
Natural airflow — strongly recommended when inverter and batteries share the same room
The majority of heat generation comes from the inverter. This is the most important variable when sizing a ventilation system.
Inverter and batteries in separate rooms
An air conditioner or heat pump works well in this configuration.
Ensure direct extraction of warm air from behind the inverter — use either a large hood covering the entire rear, or a sleeve coupling (stos) mounted over a corresponding opening in the grill
Install a T-junction and a damper (spjäll) behind the inverter to recirculate warm air within the room when the fan is inactive during winter
The inverter must not be cut off from airflow under any circumstance
KanFLEX can manage damper opening (24V or 230V) based on inverter temperatures
Be cautious of potential overcooling of batteries positioned in the direct air output from the inverter
Allow sufficient space around battery racks for proper air circulation to avoid temperature stratification:
Inverter and batteries in the same room
Natural airflow is strongly recommended in this configuration. It is very difficult to cool inverter exhaust air enough — using an air conditioner in this layout risks the cooled air being directed at the batteries and causing temperature stratification or overcooling.
Airflow sizing
Use this formula to estimate the minimum required airflow:
Total inverter power (kW) × 6.6 = total airflow required (m³/h)
For example: a 180 kW inverter requires approximately 1,188 m³/h.
Layout and ducting
Ensure direct extraction of warm air from behind the inverter — use either a large hood covering the entire rear, or a sleeve coupling (stos) mounted over a corresponding opening in the grill
Install a T-junction and a damper (spjäll) behind the inverter to recirculate warm air within the room when the fan is inactive during winter
The inverter must not be cut off from airflow under any circumstance
KanFLEX can manage fan speed (0–10V) and damper opening (24V or 230V) based on inverter and battery temperatures
The back of the inverter should not face the batteries
Allow sufficient space around battery racks for proper air circulation to avoid temperature stratification:
Fresh air intake should be positioned near the ceiling, close to the batteries:
For extended ducting runs, install an intake fan on the roof and an exhaust fan behind the inverter to avoid pressure drops
Ensure all doors are properly sealed with rubber mouldings (tätningslister)
Keep the room clean — where needed, wear protective clothing when working in the room to avoid accumulation of dust
Real-world examples
The table below shows two working installations. They illustrate the variables that need to be accounted for when designing the ventilation system.
Parameter | Example 1 | Example 2 |
Main fuse | 400 A | 800 A |
Inverter size | 180 kW | 240 kW |
Number of inverters | 2 | 1 |
**Total power** | **276.8 kW** | **240 kW** |
Fan type | RS 160 C1-y1 EC | K 315 L EC |
Fan power | 124 W | 331 W |
Max. theoretical airflow per fan | 1,044 m³/h | 1,960 m³/h |
Number of fans — intake | 0 | 1 |
Number of fans — exhaust | 2 | 1 |
Air recirculation valve | 2 × 160 mm | N/A |
Filter box | FLF315 | FFR400 |
Filter class | F5 | M5 |
Pressure drop — filter | 150 Pa | 40 Pa |
Pressure drop — ducting | 10 Pa | 30 Pa |
Real total airflow | 1,900 m³/h | 1,847 m³/h |
**Cooling power** | **287.9 kW** | **279.8 kW** |
Component selection guidance
When selecting ventilation components, the following factors have the greatest impact on system performance.
Fan type
Determines the system's ability to move air effectively. Different fan types — centrifugal, axial, and mixed-flow — have varying pressure capabilities and efficiency levels. Choosing the wrong type can lead to insufficient airflow.
Filter box
Acts as the housing for air filters and ensures proper air distribution across the filter surface. The box must prevent air bypass, ensure all air passes through the filter, and allow easy access for maintenance and filter replacement.
Recommended filter boxes: FLF315, FFR315, FFR400
Not recommended: FLK315 or FFR250
Filter class
Defines the level of air purification. Higher filter classes remove smaller particles but create a greater pressure drop, which requires a stronger fan and more energy.
Duct length
Affects the total pressure drop in the system and therefore the required fan power. Longer ducts create more resistance to airflow and must be accounted for when sizing fans.