Charging Plug-in is not good for the battery

That isn't possible with Prime. Toyota's system prevents charge-rate from that situation by keeping it low, which is why initial charging is slow during the winter if you don't have the battery-warmer enabled.

 

They have to keep it really low. Plating is temperature and current dependent. Even at 54°F you can induce heavy plating at 1C, which the Prime cannot do. However, even C/2 (which is close to the Prime's Level 2 rate) will induce some plating at that temperature*. As temperatures get lower the plating gets more severe. In subzero weather you'd have to charge at around 0.02C to avoid it.

* Burns, J. & Stevens, D. & Dahn, J.. (2015). In-Situ Detection of Lithium Plating Using High Precision Coulometry. Journal of the Electrochemical Society. 162. A959-A964. 10.1149/2.0621506jes.

 

I owned a Prius PHV in Minnesota for 5 winters. It didn't have a battery-warmer. It was just fine. I recharged at work, parked out in those frigid temperatures. When I sold it with 92,000 miles on the odometer, the pack was still delivering 13 miles of EV... just like it did on that same commute under the same conditions when I first bought it. No big deal. Toyota clearly figured out how to manage charging under those conditions.

It likely comes down to well refined software. We see the sudden, predictable drop patterns during charges in the cold with Prime. That's clear evidence of the system being aware of charging conditions and doing something accordingly to adapt.

 

We acquired our Prius Prime in August of 2017. Shortly thereafter, we set up an email address to receive charge completion notifications from Toyota's Entune and to forward those notifications as text messages to my cellphone and to Mrs. Bear's cellphone. My email system also has archived those notices and now shows that it has received 2,040 notices since Sept 10, 2017. Of those 2,040 notifications, 12 were related to account set-up and maintenance (like password changes), 3 were "charge failure" notifications that for some reason the Prime was connected to an EVSE but charging did not begin, 5 were "charge interruption notifications" indicating that the Prime was unplugged before reaching full charge, and 173 were reminder notifications saying that the Prime was parked in our garage or near our house and not plugged in to its EVSE.

That means that over the past 44 months (since September 2017) our Prime as been brought to full charge 1,847 times -- which is about twice daily on average, more or less.

It's worth noting that some of these charging cycles are returning the battery from 50% or 75% back up to full charge after returning home following a short trip to the local supermarket or similar errands.

We've noticed no degradation in the battery and still experience about 32 miles of range from early spring to late fall, and 27 miles of range in the colder months. Our driving pattern is primarily urban, although we have made a few longer vacation trips involving use of the gasoline engine.

Admittedly, we don't put in lot of miles of driving. But after over 1,847 charging cycles, I'm pretty comfortable that the Prime will have a good useful life without my stressing over any sophisticated charging protocol.

 

That is pretty great to know that its working so well after that much real life use. Hopefully the Toyota Engineers put that much thought into the programming on the cooling side, we have days down here where it never drops below 100 degrees even at night. I'm going to check my manual to see if that e-mail feature is available down on the plus version.

 

Almost. But it could be improved. If it's hot when you stop the car, it will ask if you want it to use cooling when it charges. Nice! But if it's not hot, it assumes that it won't be hot when you decide to charge it however many hours later so you won't get the option to enable it. And there's no way to make it a permanent setting like so many other things you can customize. They've had years to fix this, but they don't seem to care.

Still, even though it's not quite as hot here, it is pretty hot. My '17 still takes the same charge and has the same EV range as when I got it over two years ago. Based on the ECO history, the original owner never charged it more than a handful of times. It'll turn over 52,000 miles in the next week or so. It had about 22k when I got it.

By all means check to be sure. But afaik, that's a feature only for the Advanced trim. And it requires a subscription, iirc.

When I installed the 240V outlet for my L2 EVSE, I included a meter that tracks how many kWh is uses. It won't give me any sophisticated data, but I have the essential of knowing how many kWh per charge and how many per tank of gas.

 

I don't understand the "advice" from your friend, it just doesn't make sense considering what car companies tell us plug-in hybrids are for. I charge daily or more depending on need and/or anticipated driving. Most of our driving is local short hops. Almost 1500 miles on our first tank with 54 miles to empty.

 

almost 4 months, and i don't understand the o/p

 

It's not technically wrong to say that charging is bad for the battery. Driving is also bad for tires and brakes.

 

...and living is the #1 cause of death.