Sorry if this has been brought up before. I just heard a noise very similar to the sound from the battery area when it is charging. Different in that is was a little quieter. Car was unplugged and had not been driven for 4-5 hours. Sitting in the garage, temperature was about 12C/54F. The charge from the app was about 85%. I have read the streams about parasitic battery drain and no mention of this. I plugged the charger back in, did not change. Unplugged it and the noise continued but stopped eventually. Plugged the charger back in and began charging. Any ideas?
If the traction battery charger is plugged in, the 12v battery is also being charged (although it may be a very low current charge). There is a fan on the traction battery charger that comess on to cool the DC to DC battery charger. I can hear the fan every time I plug the traction battery charger into the Level 1 or Level 2 120vac or 240vac outlet I use to charge the traction battery up at home.
Check your Owner's Manual, page 6 (my screen image snipping has changed, so don't have that now): 6 ... Noise from under vehicle after turning off the hybrid system Approximately five hours after the hybrid system is turned off, you may hear sound coming from under the vehicle for sev- eral minutes. This is the sound of a fuel evaporation leakage check and, it does not indicate a malfunction.
Timing is just about spot on. Very impressed that you read and found that in the owners manual. Better person than I. Thanks
^ I didn't actually go read your entire OM, for a year and model I don't own. That question has been brought up several times a year, across the entire Toyota hybrid line, the entire time I have been a member of this forum, so I knew the keywords to very quickly find it in the OM. Which I also knew where to find online very quickly.