Future Owner Charging Questions

First of all, that buffer is false. In the technical-discussion forum, it was reported that the battery charges to 4.05 V per cell at 100% MFD SOC, which corresponds to an actual SOC of 95%, which is nowhere near your number.

Second, the ideal storage SOC is 30%.

Third, repeating the obvious one more time—there is a reason Toyota provides a charge-schedule function. It is not there just because. It is there to extend the battery life and maintain the battery capacity.

 

Ok
I understand your point
just to mention that for a gen 4 prime (2017-2022) having 95 cells ,the nominal voltage per cell is 3.7V , the BMS not permit a discharge lower than 3.48V and will not permit a charge over 3.98V. Don't know what are the specs for a Gen 5 Prime..
For long time storage and for the the charge-schedule function ,I do agree with your statement , apparently for gen 5 prime, the departure time seeting function has been removed ! If true, is it because of the the battery config or changes of the BMS.!

 

They probably decreased the percentage buffer in Gen 5 because it has a higher capacity.

It is strange that they removed the departure time—perhaps they thought it was redundant or didn't work well.

 

I figured the charge schedule was for those of us on time of use billing, namely my cheap rate is from 1900-0700

 

■Capacity reduction of the
hybrid battery (traction battery)

The capacity of the hybrid battery
(traction battery) will decline gradually
when the hybrid battery (traction
battery) is in use. The rate at which
it declines will differ in accordance
with environmental conditions and
the way in which the vehicle is used.
Observing the following can help
suppress battery capacity decline.

●Avoid parking the vehicle in areas
with a high temperature under
direct sunlight when the hybrid
battery (traction battery) is fully
charged.​

●Avoid accelerating and decelerating
frequently and suddenly when
EV driving.​

●Avoid frequent driving near the top
speed for EV driving. (P.79)​

●Leave a low level of charge in the
hybrid battery (traction battery)
when leaving the vehicle undriven
for a long period of time.
After confirming that EV mode or
AUTO EV/HV mode has switched
to HV mode, turn the power switch
off.​

●Use the charging schedule function
as much as possible in order
to fully charge the hybrid battery
(traction battery) immediately
before starting off. (P.123)​

Also, if the hybrid battery (traction
battery) capacity reduces, the distance
that can be driven in EV mode
or AUTO EV/HV mode decreases.
However, vehicle performance does
not significantly become worse.

 

BTW, at least for me that feature has an embarrassing bug! The car can't charge across midnight!! If you set a timer that starts before midnight it stops at midnight no matter what. You can't even set a second timer to charge after midnight.

will

 

There are also a couple of MID gauges that reset at midnight while driving at that time.

 

vvillovv: Ooh, did not know that. I'm not sure the last time I ever drove around midnight, so not a condition I would notice. Good to know though if I do at some point.

will

 

Why 30%?

 

Just where most Li-ion chemistries like to be sitting at for extended periods. Also allows for some level of self discharge without worry of it getting too low.

Unless to car is going to be parked for a month or more, it probably isn't something to worry about.

 

Hello everyone.

This thread has been very helpful. My 2024 Prius Prime SE is due to be delivered sometime next month, so have a few weeks to read up about relevant topics like this one. This will be my first plug-in hybrid.

I general, my SE will get driven less than most cars. It will sit in an insulated garage the majority of each weekday, and will likely get only get driven each daily for school pick up or random errands throughout the course or the day. I think I’ll likely only drive it approximately 10 miles/weekday.

As a result, it probably makes the most sense to plug it in each day, but set the charging schedule to charge during the night (when rates are least expensive) and to stop charging during normal working hours. Does this seem reasonable?

 

No point plugging it in every day if you're really only doing 10 miles, and you don't benefit from battery heating - every 3 or 4 days would be enough. And that will keep the average charge level lower, which should help battery lifetime.

 

That’s a fair point, thank you for making it.

I haven’t seen the charge scheduler yet, but is this something that can be scheduled? I ask because: a) I don’t know how flexible the scheduling software is; and b) I don’t want to forget to plug it in every few days if that ends up being the most appropriate charging schedule for my use case.

 

You can set charging events for particular days of the week, so you could tell it to fully charge Wednesday and Sunday night, say.

You could also set it to charge for 1 hour every night. That might be something that would make sense in a cold climate, where you want it plugged in for heating, but don't need it to fill.

 

Thanks for clearing that up and detailing how flexible the charging scheduler can be.

I live in upstate NY, so it’s typically fairly cold in winters. But the Prius will be parked in the garage most of the day, where the temp doesn’t really get below ~45 regardless of how cold it is outside.

As a result, I may not receive any benefit from daily charging, at least with respect to heating the battery. That’s my current thought, anyway.

 

Yes, I've been investigating the battery heater quite closely in another thread. The heater is of use when your battery temperature is between around -15°C (5°F) and +5°C (41°F) - it doesn't seem to activate at lower temperatures, and heats up to about 5°C maximum. Unlikely to be useful for a garaged car, and turns out to not be useful for a car out in a Finnish winter a lot of the time.

 

Can you please send over the link of the thread you’re referring to?

I ask because while the SE will garaged most of the time during the work week, I can envision my spouse taking it to work instead of her car. And in that case, it’ll be helpful to learn more about the battery heater.

Thanks in advance!

 

Just adding on the plug-in-when-needed point. For city driving I am 99% electric too. I generally have an idea of the next day's errands, and only charge up if I think I may not have enough for the day. Neat part is if I guess wrong, there is always gas! The gas engine is for my 2-3 multi-thousand mile road trips each year and for those I just need a 3-minute gas stop to get 500-ish miles, not all the DC fast charging wrangling. In fact, I haven't put gas in the car in almost two months since I came back from my last long trip.

On charging schedules, the only warning is that for some reason the car will NOT charge on a schedule across midnight! At least mine won't, if yours is a 2024, may be they have fixed the bug. If you set a timer starting before midnight and ending after midnight, it will stop at midnight and you can't set a second timer after midnight either (well, you can, it just won't fire). Amateurish SW bug. I gave up on timers and just plug it in before going to bed. If not on a timer, it charges past midnight just fine.

will

 

Oh wow, that possible bug with not being able to charge past midnight in the charge scheduled sounds like a bit of a doozy. Thank you for bringing it up!

 

After you get your Prime, if you're into all the gauges that come with the car, you may find that some of the gauges also reset at midnight, according to the time the clock in the car is set to. Gen 4 doesn't automatically change for daylight savings and will be interesting to see if it handles leap year day or not.
Also, some things can change when the phone is connected to car. But all that stuff is changing now with the Toyota app if you download and use that.