2013 Prius Two has been sitting idle for 2.5 months now due to bad head gasket, so I wanted to make sure the traction battery does not get too low. When I first hook up the Prolong Charger and turn it on, it reads 214 V. After about 5 hours of charging, the Prolong now reads 239 V. According to Prolong, the traction battery should be fully charged now. When I go to (2) ACCESSORY MODE, the HSI shows the traction battery SOC at 2 bars. Anybody have any insight as to why this would be? [I really don't want to start the car as the head gasket is bad.] --- (1) Press Start Button Once: IGN-ON (2) Press Start Button Twice: ACCESSORY MODE (3) Press Start Button Thrice: OFF HSI = Hybrid System Indicator SOC = State Of Charge
Thank you kindly Mr. F. - takes some amount of worry over "is this head gasket replacement (probably) going to pan out financially" (given that the traction battery appears viable). [after performing the procedure you mentioned: at 6 bars]
Disconnecting the 12v battery did nothing for you except make the HV battery show the DEFAULT value due to the ecus losing power and all settings returning to factory default values.
Without starting the engine, is there no way then, to find out what the current traction battery SOC is? For example, if I keep it at, "(2) Press Start Button Twice: ACCESSORY MODE", would it recalibrate automatically after X minutes? Thank you!
I would say, that at 239 volts after charging using the Prolong, the battery is probably as close to 100% SOC as it can ever be, since that's around 8.5 volts per module. Even at 214 volts, it was at a decent soc. That doesn't mean there isn't a weak module in there, but for now, it's pretty well charged up. I'd be concerned about the 12v battery draining from sitting idle that long.
