HV cooling fan question

Thanks for the thoughts on flashing the ecu. I haven't consulted toyota, trying first to fix on my own.
Fan runs fine when controlled by 3rd party app called hybrid assistant. I am thinking of wiring a switched 12v directly to the fan. The fan will run a lot more...but It will keep the hv battery temp in the safe range. This is just until I find out why the cars ecu/componet is not managing the fan.

Thanks for your input!

Frank

 

The controller for the fan is in the plastic duct on the passenger side of the HV battery. Held to the duct by rivets. It's identical to the one used in the car HVAC system.

 

That box in the duct is the same thing that is responsible for the fan when Frankusa94 is using Hybrid Assistant to control it. The only difference is in what speed signal is being sent to it from the ECU.

The crux of the matter seems to be that when not using Hybrid Assistant to override the fan speed signal, Frankusa94 disapproves of the ECU's choice of fan speed.

 

The battery ecu probably IS managing the temperature just fine. When I bother to check, the temps get up to around 125°F before the fan switches on to a level that I can hear (speed 3?).

YOU seem to think that that's "too hot". Toyota made over a million Gen2 Prius, and most went for a long time without battery problems, so I'm not going to second guess their engineers on this.

Sure, keeping the battery cooler will improve its lifespan. How much longer? Toyota was balancing battery life, fan life (and noise), and effects on MPG.

Short form, do what you want, but many here think it's a waste of time to mess with the fan operation.

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