As a new Prius PHEV owner I'm spending lots of time just sitting in the garage plugged in to level 2 charging getting everything set up. Being "power on" it must be supplied by the 12v battery. Does being plugged in also keep the 12v battery charged up? TIA Don
Based on my experience with Gen4 and Gen5 plug-ins, having the L2 plugged-in does not guarantee a sufficient charge regimen for the 12V battery. Fortunately for me, I also have a trickle charger installed in every car shortly after delivery and I always try to keep both ends plugged in whenever they are in the garage. Even in demanding conditions (like very low temperatures) when the system often wakes up to condition the battery pack, the 12V battery barely sees anything close to a useful trickle. I see this every winter and summer alike while also monitoring every mA that goes in on both ends. IMO, regardless of whether we drive a lot or not, only the frequent use of a good/smart trickle charger can keep the 12V at its peak health and lasting way beyond what is "normal" for modern vehicles.
The short answer is NO. The 12V systems are turned-ON, only while the traction battery is actively charging. It's doing that to guarantee power to the cooling fans and ECU power, to supervise the recharge process. Once the charging process STOPS, everything is back to the 12V battery onboard. There is NO current draw from the wall outlet into the 12V battery, even if you leave it plugged-in. In fact the OP manual tells you to disconnect the charging cable, once it has completed it's charging cycle. Leaving the car plugged-in forces the ECU to do more frequent readiness testing - drawing from the 12V battery alone.
OP suggests they're in the car messing with stuff. In which case, activating "My Room" mode is what you want to maintain 12V and high-voltage power from the wall.
answer is still the same - only way to guarantee a fully topped up battery is by plugging-in a separate smart maintenance charger. room mode simply allows you more access to the cars accessories, more than likely taking longer to recharge your traction pack.
I don't believe that was the question - it was being asked in the sense 'am I going to deplete my 12V battery'. People are talking about their pet topic of general grumbles about the 12V charging algorithm rather than addressing this unusual question I've not seen asked before. You won't drain the 12V if My Room mode is enabled. If you don't enable it, you will be draining the 12V. Usual advice is to always use READY rather than ACC or ON to avoid 12V drain. My Room also works.
