Hello to all, I have a question about the 12v or maybe the HV battery. When I am parked in Ready mode, I have noticed that the ICE restarts alot more often than it used too. Before, when I would park in ready mode with the AC on, it used to take about 20 minutes before the ICE would turn on and then it would charge for 2-3 minutes before shutting down. Lately though, the ICE turns on after about 10 minutes and still takes about 2-3 minutes to charge. My question is, is the 12v battery going bad, or is the HV battery not holding a good charge?
What I see on my Prius is that AC is running on HV battery. So emptying HV battery depends on AC temperature and fan speed. If I have an (almost) full HV battery and AC and fan on low it takes a while until HV battery is drained and ICE kicks in. But if HV battery is low/middle charged and fan on middle/high HV battery is drained fast. At least this is the behavior on my car.
How long ago was "used to" ? It might be WAY hotter out now than it was then, running the AC harder and using more power.
I purchased a Veepeak OBD2 scanner in May. That is when I started paying attention to the battery cycles. My Prius is a 2012 and currently has 130,000 miles on it.
Assuming similar states of charge for the traction battery and similar temperatures and other loads, if it's starting the engine sooner than it used to because of the A/C load, that's a sign that the traction battery is loosing capacity. Dr. Prius or Techstream will help you to put some numbers on the condition.
"The A/C load" can vary, though, from over two thousand watts, to a couple hundred at lowest continuous power and less than that with on-off cycling. All depending on a bunch of things like ambient temperature, insolation, and humidity. Unless you're keeping very close tabs on those factors (or have something like a ScanGauge plugged in showing A/C watts directly), it's hard to conclude much about the battery from how fast it drains under the A/C load. 2000 watts will certainly drain it faster than 200.
Like I said, it is a LOT hotter now than it was in May. You are not leaving the OBD device plugged into the car when it is OFF, are you ?
I just purchased the paid version of Dr. Prius and ran the battery life expectancy test and, assuming I did it right, it says the HV battery is at 70%. No. I don’t leave it plugged in.
