Battery capacity?

It’s about 12 kWh, and no option for increasing.
EPA rates it for about 40 miles ev range and 500 gas.
120v evse, wheels powered by engine, motor or both.
Takes about a year to get one unless you’re really, really lucky

 

and a much better value / $ option - find a USED 2019-2022 Prius Prime, that sells for less than $25k

Qualifies for a used EV tax credit of $4k. Might be other incentives also. Example SCE (SoCal Edison) gives you another $1k rebate or $4k if you meet lower income requirements. If private party, look into KeySavvy to qualify for dealer requirement and still get the tax credit.

Make the cost for a used Prius MUCH more compelling vs the 2023 Prime, that has $0 federal tax credit. Unless you really value the extra HP and kwh.

 

I've had my 2024 Prime XSE Premium for 3 weeks and I'm still trying to determine my EV only battery capacity. There is a huge discrepancy between what the Toyota app and the Enel X app says.

Known: Traction battery capacity - 13.6 kwh. ICE kicks on when the nominal % remaining on the display drops to 0%.

Toyota app: Plugging it in at this point prompts the Toyota app to display "charging started, battery at 30%." If this is true, that would leave 9.5 kwh available for EV only mode and it should take 9.5 kwh to be back to 100% charge. So far, when the battery is fully charged, the Toyota app says that about 7.1 kwh have been delivered. If that is true, the useful range for EV is only about 52% of the total capacity. I'm glad to read that the app is not very accurate, because I don't believe either of these results.

Enel X app: I installed a level 2 charger, the Enel X JuiceBox 40 because I already had a 240 V 50A line with a NEMA 14-50 plug. Overkill for this vehicle, but it allows for future growth. The charger app indicates that it takes about 11.6 kwh to go from nominal 0% to 100% charge. I'm inclined to believe this over the Toyota app, but that would mean that 85% of the battery is available for EV only mode. If the charger app is correct, it takes about 3.5 hours to charge from 0% to 100% at a rate of 3.7 kw. The charge rate drops to about 40% of that when the battery is nearly full.

 

For what it's worth, I use a smart plug to monitor energy usage on the outlet the lvl 1 charger is plugged into. With an "empty" battery, it typically takes about 13.8kWh to get it to full in just shy of 10 hours. It claims it pulls about 1.4kW during charging, so that math works out. I have no idea how well that plug is calibrated, so it could be off a few percent.

 

Interesting. Isn't the total battery capacity 13.6 kWh? Even if the plug calibration is slightly off, it sounds like you are able to completely drain your traction battery. My ICE kicks in when the nominal value goes to 0%, although the gauge shows plenty more charge for HV driving. Depending on what app to believe, my "empty" is then somewhere between 1.9 and 4.1 kWh. There's another interesting thread that suggests energy usage monitors are accounting for all energy used for charging, but line losses and AC/DC conversions zapp some of that energy. That would make more sense if it takes you 13.8 kWh to charge from empty, but not all of that is getting to the battery.

 

Yes, there are losses in the charge process, but I suspect the true capacity of the entire battery is more than 13.6kWh. I'd love to know how much they reserve for hybrid mode once it shows 0%.

 

No, 13.6kWh is the full nominal capacity. Difference between the top of "---" and "100%" on the car's display is around 10.5kWh. There's about 1.9kWh (14% of nominal capacity) below "---" (of which it would use less than 1kWh), and about 1.2kWh (9% of nominal capacity) above "100%" that's never used.

(Those percentages come from my own Techstream SoC readouts, which seem to be based on the nominal capacity, and are consistent with other people's estimates of the used capacity).

You must be losing at least 2kWh if the input is 13.8kWh - (up to 1kWh could have gone to filling up the HV reserve if that was low).

 

So, what portion of the 13.6kWh is specifically reserved for HV use? The other possibility is the calibration on my plug is off. I need to get a current clamp and see how it compares. The MID usually shows the HV portion as full when I start charging.

 

I don't think we've got an exact figure for how wide the HV range is. It'll be somewhere in the 0.6-1.0kW area. But as you said, the display usually shows that it's nearly full, so I doubt was a significant factor in your case. It seems like there's probably 3kW unaccounted for. That's quite a lot of loss, even for 100V charging. Battery heaters could have consumed a fair bit, perhaps.

 

OBD scanner shows battery at ~14.5% when MID says 0% (---%), and ~91.5% when full, So we get about 10.5kWh to play with for EV only (13.6kWh * 77%). I measured L1 power draw with Kill-A-Watt meter and it was about 13.4kWh to get 10.5kWh into the battery. I expect a decent L2 to be in the 11.5kWh range from the grid. So all math adds up. In 2 months / 2000 miles I owned my SE I ended up doing about 65% EV, so yay, saved about $25 on the c/mi difference between gas and power cost. Almost paid for half of the just copper wire cost to install the 240V NEMA

 

Wow. I never expected there would be that much loss with a L1 charger. Do you think powering the same Toyota charger with 240V would increase the efficiency or do you think these losses are mainly due to the charger itself?

 

I ended up getting an official L2 EVSE with a NEMA 14-50 plug (in my case off a 2022 Leaf), but now I can't measure what's coming out of the grid. I've seen vids of people running 240V to the included Toyota EVSE and I don't doubt it can handle it, but the rigged plugs that people did turned me off that approach. If you have a Toyota 240V EVSE with a proper plug, all signs point to it being at least twice as efficient as 110V, just by comparing charge time (10 hours vs. about 3.5 hours, less time to burn those overhead electrons).

 

As another data point, last night I charged (again from 0% to full) using the same set up, but also inserted a Kill A Watt into the chain to see how its reporting compared. The Kill A Watt said 12.9kWh and the Sonoff plug said 13.5kWh. They are close enough to assume the true power usage for L1 charging is somewhere close to that range. I think I'm going to need to come up with a plan to rig up and monitor a L2 charge cycle...

I guess the next question to ask is, "Does L2 charging cause more or less damage to the battery long term than L1?" I would think that it would cause more due to the extra heat generated, but perhaps Toyota has compensated enough for this with fans/cooling so it's negligible.

 

My assumption is that L2, especially at our 3.3kW is nothing compared to 350kW proper EV chargers...

 

To follow up on this some more, I converted the OEM charger to L2, and now it takes about 11.3kWh to completely charge the car. For reference, it took about 13.5kWh when I was using the same charger at L1, so that is a significant efficiency improvement.
Next, I'm going to put the car in 8A max mode and see how the efficiency compares at L2.

 

How do you measure 2-phase power consumption? I wired the NEMA plug and got a newer Nissan 240V EVSE for it, but lost ability to measure actual consumption (used to use Kill-A-Watt with 120V Toyota EVSE, same 13.4-13.5kWh for full charge as you see, btw).

For now I just assume 10% overhead for my OCD spreadsheet

 

I have an Emporia Vue 2 that I flashed with ESPHome doing the measuring. I was careful to get everything calibrated properly before I started logging data.