Real Prime Battery Capacities

All of the above.
Both drawing the battery DOWN too far and over-charging it will shorten it's useful life.
There is a margin built in to try and be sure that never happens.......or seldom at least.

 

10.9 kWh is incorrect.

EPA lists the useable battery capacity for all PHEVs and BEVs, just like it lists the fuel-tank capacity for all engine-equipped vehicles.

Useable BEV battery capacity (kWh) = 33.705 kWh/ge × BEV range (mi) / mpge

For 2023 Prius Prime, it is:

SE: 11.7 kWh
XSE/XSE Premium: 11.5 kWh

So, if you average the two, it is about 11.6 kWh. The SE value is probably more accurate, as the numbers going into the calculation are larger. Therefore, if the HV reserve is about 1 kWh, the lower and upper buffers are about 1 kWh total.

 

The standard Prius Hybrid Lithium battery has a total capacity of .91 kWh. So Toyota would keep a buffer that large for hybrid only operation. Toyota also won't let you charge the battery all the way to 100%, so the leftover buffer from is mostly from 100%. Of course Toyota won't let you discharge the battery to 0% either so it keeps a buffer to prevent you from hitting the knee voltage - the voltage of the battery cell where it drops exponentially from the 3.7 volt sweet spot. On this large battery it won't be a large buffer from the knee to 0%, maybe .2 kWh That leaves about 1.6 kWh off the top which is about 88%. Toyota has been tweaking the chemistry to get more from the battery so the newer ones will see a higher percentage of the battery used. Older Prius plug-ins have had only 60 to 65% usable.

 

The number is given by EPA. See my post above.

 

Maybe, but it's not what the car seems to be telling me. XSE owner and I've been doing a lot of testing in the first 500 miles. In terms of usable battery, the graphic gauge showing charge has the HV line about 1/3rd up from empty and when it switches into HV mode, the App shows 30% even though the EV range is zero. 30% of 13.6kw is 4kwh, a lot more than the .91kw to 1.2kw that I've seen for the standard hybrid.

Is that accurate? When I recharge, the app reports 7.1kwh for a zero to full charge. Someone else here had a similar number. 11.5 usable - 30%/4kw HV reserve = 7.5kw

That would give it a rather extraordinary miles/kwh. But the math seems to work, providing you trust the app, which I'm a little dubious about. This weekend I'm going to leave it in the commuter lot and see what a commercial charger claims it's putting into it as another data point. (Not to mention a free charge.)

 

that doesn't sound accurate, since thepip is 4kw and travels about 10 miles ev.

 

No, the BEV capacity is about 11.6 kWh and the total PHEV capacity including the buffer is 13.6 kWh; so, you are left with about 2.0 kWh for the HEV reserve and buffer. The buffer is probably about 1.2 kWh, and the HEV reserve is about 0.8 kWh.

Toyota specs the 2023 Prius HEV battery as 0.906 kWh (222 V, 4.08 Ah). The buffer in that case is probably around 0.1 kWh with about 0.8 kWh useable HEV capacity.

 

By chance the detailed report for the Prime is already available on the Epa.gov?

Please. let me understand better the meaning of "usable". On the gen4 i have been told that the SOC (i guess measured by one of the diagnostic tool) doesn't go below 14% and in any case tends to recharge with gas until it reaches 20%. Is it correct?

So, the "real usable" should'nt be some 75% of 13,6 kWh = 10,2 kWh?

 

You need to do many measurements, as your starting SOC will vary several percent around 0% due to HEV use. EPA numbers should be accurate, and you should see 11.5–11.7 kWh (more likely 11.7 kWh) on ChargePoint Level 2. You will see a higher kWh on Level 1 due to reduced charging efficiency.

 

I have explained this already. It is 11.5–11.7 kWh (more likely 11.7 kWh).

It is the energy in kWh used to charge from 0% to 100% SOC on the vehicle's display.

As I explained, you don't need the detailed data to know that. However, you can also download more data to get the shape of the drag curve as a function of speed.

 

I have explained it. Read my post carefully. The useable battery-capacity data is given indirectly through mgpe and BEV range.

Real Prime Battery Capacities | PriusChat

By the way, it is 11.5–11.7 kWh (more likely 11.7 kWh). I corrected my typo.

 

The EPA hasn't signed off on even ratings yet. The Prius Prime spec page at Toyota.com has "Projected EPA-estimated" values.

 

You are forgetting that 2023 Prius Prime has been on sale with window stickers showing the EPA values for many weeks now. EPA is not good at updating its website. Toyota wouldn't publish EPA specs on window stickers or their website not vetted by EPA. Projected means your mileage may vary.

 

But if the car doesn't allow you to go lower than 13% SOC, the available charge to do the AER range should be 10,2 kWh. Am i wrong?

 

What 13%? Is that a number shown with some OBD tool?

The formula I provided here is clear. 10.2 kWh is wrong according to the EPA mpge and BEV range. Useable BEV (not BEV + HEV) battery capacity is about 11.7 kWh and no less than 11.5 kWh.

 

The foot note for the Prius doesn't have the "projected". Same with the Crown. So neither is the Toyota site updated.

 

The EPA value of 33.705 kWh/ge × 25 mi / 133 mpge = 6.34 kWh is exactly what I get on ChargePoint Level 2 with my Gen 4 Prius Prime.

The same formula gives 11.5–11.7 kWh for Gen 5 Prius Prime. I do not expect the EPA values to be incorrect. If they were incorrect, then we could not trust anything EPA provided.

Gen 5 Prius Prime owners can report their ChargePoint 0–100%-SOC kWh here.