Hybrid Battery Health

Is your hybrid battery actually failing? Testing, symptoms, cooling performance, and replacement decisions.

Gen 3 Prius HV Battery: Why "Cooling Performance Low" Doesn't Always Mean What You Might Think

Short version: The message “Cooling performance of the hybrid battery is low” on a 2010–2015 (Gen 3) Toyota Prius means the hybrid battery isn’t staying...

Why "Check Hybrid System" Doesn't Always Mean You Need a Hybrid Battery

Short version: A “Check Hybrid System” warning doesn’t automatically mean your Prius needs a hybrid battery — it can also be an inverter fault, a...

Do I actually need a hybrid battery replacement?

Short version: If there are no warning lights on, your hybrid battery is functioning within the parameters defined by the manufacturer — a winter drop...

The 2004-2009 Prius "Triangle of Death"

Short version: The red “Triangle of Death” on a 2004-2009 Prius that flashes during braking, turning, or downhill driving—with no stored codes—is almost always low...

The Truth About Hybrid & EV Battery Testing

Short version: Your hybrid or EV already tests its own battery — the Battery Management System monitors it every second the car is on and...