Daily charging

I charge twice everyday.

You won't wear the battery down as it is designed to be recharged.

Source for your information?

Enjoy your new Prime.

 

You can charge as frequently as you wish. You may see some degradation regardless. To minimize the degradation Toyota recommends use of a charge schedule so that it stays the least amount of time fully charged.

 

Being in the northeast, you can take advantage of the climate prep at your desired set time for departure.

You may have to play around with the times, but for my 21 prime, I set it for 5 minutes after true time.
That way when we get in to take kiddies to school I can rely on my drivers seat heater to do most of my warmth
and the kiddos have their jackets on bundled up.

The Prime is very exceptional on its efficiency in driving and heating.
And will apply heat to only the driver if you have in ECO mode and nothing in the back seat.

Just remember pros and cons, the con being the EV range will be depleted faster using said Heat/Climate Prep and such.

But you should still see much higher MPG when charging each and every day/night.
Your numbers in my scenario would be roughly 75-80mpg verses the 50-60mpg w/o charging.
But do your own testing.

 

how do you know that 'many recommend not charging daily?

 

Yet, the battery can at most be charged to what maybe max 85% (even tho guess o meter will say 100%) so time spent at “fully charged” is not as serious as time spent at actually really fully 100% charged. Thus far far less to worry, yes?

 

For those of us in colder climates, looks like the PP Manual suggests the Hybrid Battery Heater will function to help that battery avoid being too cold, thus perform better, for longer, as long as it is plugged in the grid power. So if convenient maybe keep it plugged in all night every night during the cold nights of winter season?

 

Correct. Since you can never fully charge the PP beyond the upper limit threshold set by Toyota, no one knows how that affects the longevity of the traction battery. In addition, the question of how much degradation can be caused by having the car sits with the traction battery charged at an actual ~85% SoC is also unknown to most of us.

I guess if you have two same year model PP's driven in identical conditions except one being charged without a schedule thus tends to sit at 100% SoC on GOM longer than the other which is always charged right before departure, thus minimal time sitting at 100% SoC on GOM, then you can test the difference in the degradation level in a few years. But yeah, for all practical purposes, the differences are going to be so variable and depend on too many other factors, such that worrying about the degradation caused by keeping the car in a fully charged state (on GOM) for a short day or two may be unwarranted.

Still, Toyota recommends discharging the traction battery to --% on GOM (actual 10-15% SoC level) for long term storage and recommends the use of scheduling to minimize the amount of time traction battery with 100% on GOM (actual 80-85% SoC level). So, there may be some merit in minimizing the time the traction battery sits at 100% on GOM (actual 80-85% SoC level). Who knows?

 

My understanding is that the traction battery heater only works before and during the actual charging of the battery. It has to do with the fact that the lithium battery can be permanently damaged if it is charged at the battery pack temperature below 32F.

I might be wrong, but I think after the traction battery is fully charged, I don't think the traction battery heater has no function to keep the battery heated. Keeping the charging cord plugged to the wall after the charge is completed, only drains the 12v battery quicker. If you want to maximize the efficiency of the traction battery, then scheduling the charge session so that the charging finishes immediately before your departure ensures that the battery pack is nice and warm from the active charging process.

 

That makes me wonder, if whenever plugged in and not charging, if the PP takes advantage of grid power to trickle charge the 12V battery to avoid the vampire drain? I know the Chevy Volt did so. Maybe?

 

no, it actually drains the battery unfortunately.

 

The answer is NO. At least from my observation of the 12v battery voltage reading on PP.

I will be writing up the summary of my finding on a new thread soon, but what I know now is that PP charges the 12v battery at ~14.4v while the car is in READY mode (no need to be driving or engine starting). The DC-to-DC converter charges the 12v battery as needed.

While the PP is plugged in with EVSE, it seems to have two levels for charging. The first is ~13.5v charging which occurs only during the time the traction battery is actively being charged. I have never seen this active charging occurring outside of the period of the traction battery is being charged, even if the EVSE is kept plugged in after the traction battery charging has finished. The second is ~12.7v maintainer mode charging that just keeps the 12v battery at near a full level without actively bringing the SoC any higher. This too only happens during the time the traction battery is actively being charged. There is one more mode that seems to check the voltage of the 12v battery and charging at 13.5v starts, but immediately stops and switch back to the maintainer mode at ~12.7v. This one is hard to catch and I don't know the reason why sometimes PP does this not all the time.

One question I have not solved yet is that what causes the PP to change the behavior of the 12v battery charging. With the same 12.38v resting voltage of the 12v battery, I have seen PP does either active charge at 13.5v or maintainer charge at 12.7v. Certainly, if the 12v battery is healthy and fully charged at above 12.6v, it seems PP preferentially keeps it in maintainer mode. But as the 12v battery loses its capacity, and drops below 12.4v, it sometimes triggers the active charging at 13.5v, but not always the case.

 

I thought the chemical property of the lithium battery does not allow the charging at below freezing... However, I admit that I am not a chemist or engineer who can answer your question. But, yes, the battery will operate and the car will start well below the freezing mark, even though the manual says something about extreme cold may cause the Hybrid System to not operate, I have never had that experience. I just thought the temperature of the battery pack had to be raised to above freezing in order to charge, but not to operate. Once charged, it can sit below freezing temp and still starts fine.

 

Based on my interpretation of Prof John Kelly's video, the 5 battery heater grids come on (when charging the traction battery) from 2-5 Celiuis or 35.6-41 Fahrenheit. Total of about 200-watt heater at 14 volts. For cooling, the 12 volt battery is maintained at 14 volts while charging so that the two cooling fans can function in addition to running air conditioning compressor (if needed). In either care the 12v battery is being charged to 14 volts.

 

That is my understanding, but the heater has to come on before the active traction battery charging starts to prevent permanent damage to the battery.

From my observations, the charging of the 12v battery, while the traction battery is being charged, occurs only occasionally. I have not figured out the rules for this. Also, the charging of the 12v battery while EVSE is attached never exceeds 13.5v in my experience. This is a distinct difference from the charging of the 12v battery during READY Mode when the voltage stays well above 14.0v, usually around 14.4volt.
See this thread for further discussion: Hopefully, ultimate 12v battery charging system discussion on PP | PriusChat

 

The battery most certainly does charge below 0C/32F as I’ve done it at least a dozen times in past few weeks (between 0C and -15C on various overnight charges at L1 set to 8 amps). I have not used the battery heater as I believed (apparently erroneously) the system would ask if I wanted to engage it, much like the cooler setting in warm weather. While I will make sure to turn on the heater from now on, it clearly can take a charge at sub-freezing temperatures.

 

same with the pip. perhaps heat makes it more efficient, and/or extends longevity?