Battery Coolant Heater – 1.5 Series

Battery Coolant Heater (Inline Electric Heater, HVAC Thermal System) – 1.5 Series

The Tesla Roadster Battery Coolant Heater for 1.5-series cars is an inline electric heater installed between the battery coolant pump and the heat exchanger. During cold-soak conditions it warms the coolant so the ESS (Energy Storage System) reaches the minimum temperature needed for safe charging. The heater is powered from external AC line voltage (via the PEM and charge hardware) and is commanded by the 12 V control system based on battery temperature and humidity feedback.

This assembly is critical for owners in colder climates: without a functioning battery coolant heater, the Roadster may refuse to charge or significantly limit charge rates when the pack is cold.

Why these heaters fail

• Thermal cycling & age — Repeated hot/cold cycles stress internal elements and seals, eventually leading to open circuits or internal shorts.
• Moisture ingress — Exposure to condensation or coolant leaks can attack internal insulation and wiring.
• Connector / harness issues — Corroded pins or damaged leads can cause intermittent operation or heater faults.
• Insulation breakdown — Over time the high-voltage isolation can degrade, triggering isolation or ground-fault errors during charging.

Common symptoms of a failing heater include charge refusal in cold weather, “pack too cold” messages that don’t clear, or diagnostic alerts related to the battery coolant heater or isolation faults.

Our solution

• Correct Roadster 1.5 fitment — Cylindrical in-pipe heater assembly built for the 1.5-series Roadster battery loop, with the proper hose connections and harness lead length.
• OEM-equivalent assembly — Direct replacement for the factory battery coolant heater used on pre-2010MY Tesla Roadster 1.5 vehicles.
• Fully tested before shipment — Every unit is bench-tested for correct resistance, isolation, and operation under load so it arrives ready to install.
• Protects ESS life — Restores proper pre-heat behavior so charging occurs within Tesla’s designed temperature window, helping preserve pack longevity.

Recommended service interval

There is no formal mileage interval, but we recommend proactive inspection or replacement when performing major ESS service, after any isolation-fault event, or whenever cold-weather charging issues are observed.