Universal Heater Unit Kit

A complete cabin heater unit for a conversion: a 2.4 kW PTC heater, its controller, and the box that holds them, running from a 300 to 400 volt pack.

Cabin heat is the problem people leave until last and then find is not simple. Take the engine out and there is no hot coolant, so the matrix does nothing. A PTC element replaces the heat, but on its own it is an element: it still needs switching, controlling, fusing, mounting and integrating with whatever tells it how warm the car should be.

This kit is all of that, assembled. Heater, controller and enclosure together, with CAN and low voltage signalling including HVIL support, so it behaves as a managed part of the vehicle rather than a heater someone wired to a switch.

PTC means it regulates itself. The element's resistance climbs as it heats, so it draws heavily when cold and progressively less as it comes up to temperature. It cannot run away and it cannot glow red if the airflow stops, because the physics limits it rather than a controller.

HVIL support is the detail worth noticing. A high voltage heater with an interlock in its connector means the contactors open if someone starts to disconnect it, which is what you want on a 400 volt appliance mounted behind a dashboard.

Key specifications

Features

• Heater, controller and enclosure supplied as one working unit
• Self regulating PTC element, which cannot run away
• CAN controlled, so the vehicle manages cabin heat rather than a switch
• HVIL support, so the contactors open if the heater is disconnected
• 2.4 kW, enough to heat a cabin rather than take the edge off it

Compatibility

For packs running between 300 and 400 V DC. Check your pack voltage at both ends of its range, not just nominal.

It needs a CAN master. The unit expects to be told what to do. Something in the vehicle has to command it, which means a controller with a CAN interface and the heater's message specification.

Plan the ducting. A heater box produces hot air and something has to get it to the vents. On a car whose original heater box is being replaced rather than reused, that is the part of the job to think about first.

The user guide in the Documents tab covers the wiring and the commissioning.

In the box

• 1 x heater box with 2.4 kW PTC element
• 1 x heater box controller

Downloads

The user guide and a 3D CAD model in STEP format are in the Documents tab. Read the user guide before wiring: the supply, ground and CAN requirements are all specified there.