2018 Prius Prime EV battery problem

a good measurement of battery health is kwh accepted during a full charge from empty to full.

 

not that i know of. some public chargers will give you the info, others have a watt meter in between the evse and the wall plug.
you can find threads here on how and what prime owners measured

 

I am experiencing this problem, visited my dealer as was told pretty much what I see in the responses to your post , however I also notice that the indicated time to full charge from no charge is way off. It was pretty accurate at 5 1/2 hours and still says that but the charging stops after 4 hours. Seems to me this is not right.

 

The EV range indicated on the GOM (Guess-O-Meter) is just an estimate. It changes wildly depending on your previous driving records, current environmental variables such as temperature, and other unknown factors.

I don't pay much attention to what the EV range says on the dash. I can have the EV range saying 20miles and drive the car 30miles, or the EV range saying 30miles and can only get 20miles out of the car. This happens to my PP all the time.

As for the charge time issue you described, does the car show the "charging complete" on the dash after the charging session and show 100% SoC on the battery icon? If not, then the charge session was somehow interrupted. How did you assess the charge level and when the charges stopped?

 

I have this problem with my Prius Prime. For the first 5 years of driving the display range indicator was pretty predictable. Although it did vary day to day due to temperature, driving route and things like that I would get pretty consistently between 30 - 32 miles on a full charge in the summer and 20 - 22 in the winter. In Nov of 2021 as the seasons were transitioning it went down to around 16 - 17. During the warm season of 2022 it ranged between 22 - 24. I've brought it in to the dealer twice and they honestly just don't know how to do any testing on it. The service rep at the dealer, who is a friend, said in the 6 years he's worked there they have never replaced a hybrid battery (plug-in or conventional) under warranty. I'm curious if you have any updated information with your car. I'm planning to start monitoring some of the data mentioned in some of the responses. I got a power meter that I can use to measure kw consumed to get to full charge. I wish I had that from new for baseline. I'm looking into the obd to get the detailed information on individual cells in the battery.

I read somewhere, but I can't remember where, that there are aftermarket services that will replace individual cells in the battery to bring it back to full capacity. Have you heard anything about this?

I also can't seem to get any answers to the question what hypothetical problem with the battery will prompt Toyota to do a warranty repair? The service tech at my dealer doesn't even know of any criteria to consider a battery bad.

 

once you het some readings, post them here. other owners who have recorder them since new can give you advice as to whether you're having a problem or not.
plenty of non hybrid batteries have been replaced, both at dealers and other places, there's a whole industry.
only a few plug in batteries have been replaced since toyota started mamaking them in 2012.

replacing individual cells (modules) can be done, but it requires knowledge and time to do it right.
no aftermarket companies have proven reliable on a regular basis, and toyota won't do it.
the dealer can use tech stream software (or you can diy, but it's complicated) to measure the cell voltages under load, and see if any are out of parameters. but if they were, you'd get a trouble light on the dash.
and that's the only way toyota will perform warranty, you need the trouble light/code.
the manual states that range loss is normal, and not covered under warranty.
it does sound like you need a more knowledgable dealer, but unfortunately, no one will be able to help you.
when you get your kwh readings, i suggest starting a new thread

 

The first thing you need to know is your miles per kWh. Multiply that by the miles you drive before the EV range is used up. This is NOT the GOM meter number. You need the actual miles driven. Divide the miles by the miles per kWh and you will know how many kWh of battery you used. That's the useable portion of the battery's 8.79 kWh full capacity. Useable portion of a new one is roughly 6.2 kWh depending on who you ask.

Note that Toyota has no warranty on the capacity. You could be down to one mile of range and if there's no trouble code, you're on your own.