Prime hybrid mode extended time performance?

The Prime functions basically like a normal Toyota hybrid with extra battery capacity you can fill from the mains.

When the external charge has run out, you're left with a car that runs basically the same as a normal Prius hybrid, with roughly the same efficiency.

It uses a small portion of the big battery's capacity to provide basically the same experience as the normal hybrid does with its smaller battery.

If you're thinking about lifetime of the battery, keeping it "empty" (ie in the HV range) is better for life than keeping it full.

A couple of relevant points from the manual:

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.

Also, even though the EV driving range becomes shorter when the hybrid battery (traction battery) capacity reduces, vehicle performance does not significantly become worse.

The Prime will basically never lose HV efficiency, just EV range - it's battery is massively oversized for HV operation. The HEV would find battery reductions eating into its efficiency.

It's not unlikely that an HEV will eventually need a battery replacement before it's retired. A PHEV should manage with never getting a replacement - it would be far more expensive, so you can just accept gradually getting less EV operation.

 

The battery charging data on my Prius Prime 2023 is interesting, went through the numbers. It only cycles from 24% to 76% of the actual battery capacity, and uses 7 kWh of it's capacity for EV driving. If you look in the mobile app, when I run the traction battery down to 0% on the dashboard, the mobile app shows 32% capacity. It takes 7.004 kWh to charge it to 100% -- when it displays 100% in the mobile app and the dashboard. That means 100% = 7.004/0.68 = 10.3 kWh, and 32% is at 3.3 kWh. The published capacity of the battery is 13.6 kWh. So it is cycling between 24% and 76% of it's capacity. That's how they prolong the life, never fully charging and never fully depleting. Your phone is cycling from 0% to 100% or at least much closer, and getting hot if you fast-charge it, so it doesn't last as long, but then phones aren't expected to last as long.

 

ken2023, sounds like you're using a Toyota app which hasn't been properly updated for the 2023 Prius, and gets confused. There's been a fair amount of discussion of that here, eg:

2023 Prius Prime - Share Your EV Mode Range, Rate | PriusChat

Getting the range it gets on only 7kWh would mean it had to be implausibly efficient. The used capacity is more like 10.6kWh. But the general point about never fully emptying or filling is correct.

 

Got a tablet that offered a switch to charge to 85% and discharge to 15 for exactly those reasons. Extend battery life.

 

Well! So much for that calculation, garbage in garbage out. Thanks for the tip.

 

It's purposely designed to operate that way. When the dashboard reads 0% or 0 EV miles, it has enough charge for the car to operate in true HV mode. The battery would still assist with acceleration and turn off when you come to a stop etc. If the battery was fully depleted, the ICE would run all the time. That 70% of usable EV charge will still get up to 45+ miles of EV only driving.

 

A follow up question:

Assume you drive uphill for long enough to deplete the EV portion of the traction battery, at which point the car will continue in the HV mode, corresponding to the SoC let's say 20% to 30% of the overall capacity. You pass the crest of the hill and begin rolling downhill .... would the car stop regenerating after reaching the upper limit of the HV SoC, or at that point the car will (a) Continue to regenerate and (b) Switch back to the EV mode, since the battery has once again enough power to operate in the EV mode?

 

It will continue to regenerate, and will switch back to EV mode.

Manual mentions it specifically:

 

This is really smart. Proves that Toyota knows how to make electrified vehicles that make sense.

 

And if for some reason(s) the Prime wouldn't regen enough to get back into EV mode, the driver can switch to charge mode and manually start the regen to get some EV range.