[2023 Prime] Watts, Watt-Meter, and Not What

There's definitely weirdness going on with the app; I drove the battery down to "Zero miles/ zero %" in EV mode; however, the app shows "30% charge" but no miles of EV range. I am now charging, I am at 32% but it is telling me it will take over 9 hours to charge. I also notice it has adjusted the gas range from 555 miles (first fill-up) to 468mi (I assume based on my average over the first tank?). after the second fillup. Also, based on the KwH and charging percentages listed in the charging log, the capacity of the battery (100%) is anything from 6 to 11 KwH (though it does cluster right around 10). So I am not really trusting any of these figures. I agree with you that the reserve for hybrid driving seems like ~17-20% charge. But even if the car charges itself above that, you don't gain any driveable EV miles (though if you are IN EV mode and recover energy through braking, you will see the EV range go up.) My EV range has been 37-41 miles per charge so far.

 

All the apps are at least slightly different. The best way I've found to be comfortable with whatever readings an app or the cars gauges show is to compare what you see and concentrate on the readings that match or are at least fairly close to each other.
The readings that are not so close or grossly different can also be thought of as the app being configured using different baselines and needing conversions to make sense.

It's always nice when posting to share where the readings being talked about are coming from and which model and trim is being described.
thanks for sharing @nagrath

 

Thanks, will do. App is the Toyota app for Android. Car is 2023 Prime XSE.

 

Great info, this is very helpful (and nice to know I was not the only one finding those numbers really sketchy).
Where is that Avg Miles per KWH displayed? In the app or on the MFD (So many screens, I am never sure if I have seen all of them)

 

Ha! I have been driving in Hybrid mode to break in the ICE a little - and had only discovered that screen (showing avg MPG) after I ran out of EV battery - I charged overnight and boom, when I started up it was right there in front of my face. But thanks!

 

Taking a full set of pics of the gauges, at least once a year, is a good way to learn where they are and how to locate the ones you want to look at faster than scrolling through them all every time. I turn off the battery heater and turn on the battery cooler in late spring just so it will be easier to find them, since the cooler especially is buried deep in the MID's settings screens. Then I do the reverse in late fall.
@tovli I hear ya, the app sucks, what else is new? I don't know why so many people load it up on their phones in the first place, hoping it will provide them more convenience or that one feature that they seem to think they need from it that only works if all the planets align and the moon is in the seventh house.
Yous all might wanna check out Hybrid Assistant and see if that app works better with the Gen5.
Hybrid Assistant: App
and it's sister app Tire Assistant
Tire Assistant
I run them both on Android Oreo ie: 8

 

I'm new here with a 2024 Prius Prime XSE Premium. I'm glad I stumbled on this thread. I agree that the Toyota app for Android doesn't give reasonable data. It tells me that from nominal 0% to 100% charge takes 7.1 kwh. That would only leave 52% of the traction battery available for only EV mode. I've been using a level 2 charger. That app tells me it charges at 3.7 kw. 0-100% full takes about 11.6 kwh on that app. I hadn't thought about AC/DC conversion and line losses. That's very important to the overall per mile cost.

I'm trying to determine my losses. I'm getting an average displayed mileage of 4.4 mi/kwh. I haven't driven the car enough to calculate actual EV mileage yet. I've read that the battery charging current is 16A. I'm not sure how that is governed. At 220V that would be a 3.5 kw charging rate, which I also believe is the maximum. So, if my battery really is being charged at 3.5 kw, and my level 2 charger app is saying 3.7 kw, it sounds like my charging setup is 95% efficient. I'm not cooling or heating the battery. My garage has been averaging about 50 F. I'm not sure what gauge the level 2 charger cord is, but it's rating for 40A, and my circuit is 50A, so at 16A I doubt I'm getting much line loss.

That would give me a usable battery capacity of about 11 kwh (95% of 11.6 kwh) of the battery's 13.6 kwh total capacity. That seems reasonable. That would imply that about 81% of my battery is available for EV only range.

Now for getting a full charge and driving straight through under mixed conditions until 0% nominal and the ICE kicks in. Then I can get my true mi/kwh value.

 

The official EPA value for the useable battery capacity at the 240-V plug is about 11.6 kWh (~ 11.7 kWh for SE, ~ 11.5 kWh for XSE/XSE Premium). So, the app, which shows the kWh at the 240-V plug, is correctly written. Note that the app does not measure the actual kWh, but it estimates it from the SOC by scaling the SOC, assuming 11.6 kWh at 100% SOC.

Real Prime Battery Capacities | PriusChat

As far as the energy loss on the battery charger, 5% is about right.

My original post neglected the charger loss; so, the upper and lower buffers should add up to about 1.6 kWh.

 

5% is a ton better than 110V EVSE 25%+ loss (Kill-A-Watt telling me 13.4kWh to fill the 10.7kWh battery). I have a 2022 Leaf L2 EVSE from craigslist that I'm marking as 10% loss for my $ calculations, but with 2c/mile in EV benefits upgrading to a smarter EVSE is not in the future

 

Really? On my Gen 4 Prius Prime, Level 1 is not that bad at all.

 

I believe you are using an incorrect denominator for your calculations (should be the energy from the outlet 13.4). So if I'm correct the loss is 20%.

 

You are right, I didn't pay attention to what the convention is and just looked for the worst case number.

 

What is energy loss on the battery charger. If I charge at home with 110volt ???

 

Right above your question - 110V charge burns ~13.4kWh to fill up ~10.6kWh battery.

 

But you must consider what elese is being done as the traction battery is charged. The Traction Battery may be heated or cooled (Using AC chargee power or traction battery power), the 12v Battery may be recieving a small charge, and what ever elese is reqired for a prerequisite or cincurrent charger activity with the traction battery charging routine.

 

True, I tested over about 3 months, cold car, right after a trip, etc., it pretty consistently came out to 13.4-5. Maybe in the crazy hot summer it'll be different, I might try again soon.

 

Anymore thoughts on efficient charging? I charge from PV and am trying to optimize for best L2 charge rate?