Hello all, I posted a while ago about having only 45mpg on my used 2011 Prius. We found the culprit: my battery tested at 11.5 volt, instead of 12.5...so, I got a new battery. Now, I get about 47mpg and after testing the new battery (that I've had for a week), it's at... 11.6. Bought it at 30k miles, currently 45. Proper maintenance, and its cold where I am (freezing), if any of that information helps. I'm at a loss as to why my battery continued to drain upon first starting my car, why it isn't getting 50mpg, and why my brand new 12.5 battery is secretly a 11.6 in disguise.
First off, did you check the charging system when they replaced the battery? 11.6 volts is a discharged battery, quite low. I would have to say, your not charging the battery when the car is running, or you have a draw (something on like a light) that is running it down while stopped. Your other battery may not have been bad, it may have just been discharged. Gasoholic
There definitely wasn't a light on. What charging do you mean? I didn't know that I had to check anything. What should I look for?
Check the battery voltage while it's running. The ICE doesn't necessarily have to be idling; the traction battery should charge the 12V battery either way. It should be about 14V or a little more. If not, there's a charging problem.
