When the wife inadvertanly leaves the map light on all night and the SOC is showing in the red (2)bars? This has happened twice in the last three days. After about fifteen minutes of driving it will get in the green agian but mainly resides in the blue. Is it affecting the capacity of the traction battery? is this constant discharging causing a memeory in ht ebattery? Mike C 2007 Gen II Pkg IV 69000 miles
When the car is off the HV battery is disconnected so the map light has nothing to do with the HV battery SOC. The map light does put a drain on the 12V auxilary battery in the back. The auxilary battery is smaller than a normal car battery since it is not used to start the ICE. Others have reported that leaving on a light overnight can result in a dead battery. So, be careful leaving on any lights. You may want to test your battery to make sure it is still healthy.
Mike, when you turn the car off, how many bars do you have before this happens? That's not the best sign, but has nothing to do with the map light (on the other hand, your 12v battery might have to be replaced early). Are you sure it's not just that you're accelerating after turning on the car, then looking at the energy display after 20 or 30 seconds of accelerating and finding the battery in the purple? That last situation would be normal and would be nothing to worry about.
BTW, if you notice that the 12 volt battery is seriously weakened, here is an aftermarket choice. Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10
See here for the built-in (no tools needed) 12V battery test: http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html
MWP, When I find the SOC in the Purple the engine hasnt even ran yet. It is when I notice the light on i go check the SOC on the HV and it shows purple. I have parked in the blue or green and found it in the blue or green 12-18 hours later. I will get it up to green tonight and see if stay's that way overnight. Is this a sign of the HV battery pack dying? Mike C
The Prius HV battery holds its charge for a very long time. Last time when I had an 11 day off period, the SOC went from 58.5% to 57.5% (in this case the "bar" display won't change at all). If you see huge drop of the SOC overnight then it is not normal.
OK. Ran the HV Battery up to Green and it held green for 18 hours. Thats good news. Did the Starting battery check through the MFD and it showed 12.2. Thanks
The SOC display on mine sometimes drops a lot while sitting on a hot day, but there has been no change in fuel economy or performance. I suspect that the battery control system simply gets a bit confused and changes its mind about what the SOC actually is, rather than any significant degradation of the battery itself.