How to test EV battery/warranty

Besides range anxiety, slow continual battery degradation is another reason I am hesitant to buy a BEV. At least until the battery replacement gets cheap enough, I am not likely to keep any PHEV or BEV for the long haul. Besides, for PP, at least in our region, buying it and trading in every year is profitable as long as Toyota continues to offer the big rebates and tax credit remains.

 

For Li-ion, the normal capacity loss is relatively quick in the first few years, but then the rate slows down. With the ranges BEVs are at now, most people likely won't notice that slower loss. Then some manufacturers are programing the cars to have a large buffer of unused capacity. As the normal loss happens, the car unlocks some of the buffer so that the usable capacity stays constant.

 

... and laptop computers, starting before the smartphones.

 

We've had various hybrids over the years, all are still in service (four kids and four grand children). One, a 2008 Honda Civic Hybrid had the NiMH battery replaced under warranty with no further issues. A 2010 HCH has no issues. A 2012 HCH (the first year to use an Li-Ion battery) had a service recall for a software update which increased the time interval before shutting down the ICE at a stop, thus limiting the stop/start cycles. That car, as well as a 2014, 2016, and 2017 are still running okay.

We've no complaints with the current technology/longevity, but look forward to increased capacities and faster charge times.

 

Try this trick, plug in the charger while the car is on. Do this 3 times over 3 days. It normally resets the battery when you do this and you will get a crap range run followed by longer runs down the road after normal charging.

 

Never heard of that. But a couple clarifications if you would:

Do you mean "ON" mode or "READY" mode?

Is that 3 times a day for 3 days or once a day for 3 days? I'm guessing once a day for a total of three but want to be sure I have it right.

 

I did it once a day for 3 days. Basically stop, put the car in park but don't press the ignition button to shutdown the car.

it causes it to reset the battery meter. As the 3rd charge usage, I ended up getting like 4 miles from 100 percent. Then I did a normal charge after that turning the car off and going through the normal process over the next few days it realigns all the batteries.

 

Thanks. I'm still trying to make sure I have the procedure right and kind of guessing a little. I normally charge at work and not at home during the work week. But sometimes I do charge at home if I ran errands. Tell me if this is how you would do it:

• Day 1 - Get home, put it in park, plug in the EVSE cable, unplug the EVSE, turn off the car. Charge the car.
• Day 2 - Get to work, put it in park, plug in the EVSE cable, unplug the EVSE, turn off the car. Charge the car. Drive home. Don't charge or plug in.
• Day 3 - Get to work, put it in park, plug in the EVSE cable, unplug the EVSE, turn off the car. Charge the car. Drive home.

Or is it that you simply plug it in before turning off the car and then turn off the car and let it charge? Now that I think about it, this seems more likely.

Not that I think I need help with the range. I'm getting way over EPA estimates even after 4 years and almost 50k miles while driving in conditions designed to promote really bad fuel economies. But I would like to try it out to see what difference it might make on my Prime.

 

Did you ever try this? My 2017 PP battery use to top off at 30 miles under the best temperature conditions, now the best is 24.5. Last Winter I was getting 19 miles when I use to get 25. What further degradation of battery capacity is expected?

 

you're not seeing degradation, you're seeing range estimates based on past range performance.

it changes year round with the climate, driving type and hvac use

 

It didn't do anything.

As Bisco said, don't conflate battery range with battery capacity. If it takes five seconds to empty a container of liquid one time and the next time it takes ten seconds, did it have twice as much in it the second time, or did you pour half as fast? Or was it one of the infinite number of combinations of the two variables? Capacity is just one factor in battery range.

If you want to know how the battery capacity is holding up, measure the kWh required to charge it from depleted to 100% indicated. But even that will vary because it might be just barely depleted or it might be down near the bottom of the HV portion of the battery. I've had my 2017 Prime for 2-1/4 years and driven it something like 25-30,000 miles. I can't detect any change in capacity or range beyond minor random fluctuations.

 

Hey Jerry, here is interesting single-point data on the kWh measurement required to charge the traction battery to 100%. It is on my brand new 2021 PP Ltd. Just picked up two days ago. It had 8 miles on the odometer and has never been driven on HV or EV mode nor has any indication that the traction battery was ever charged. Basically, a brand new traction battery that has not seen much beyond QC steps in the factory.

I plugged it in with 0% EV after driving it home from the dealer all on HV mode ~30miles, which gave me 69.6mpg for the gas-only trip. Well, the car took the very first charge from wall 7.15kWh total. This is by far the largest draw I have ever seen on my Primes for a single charge. I do remember seeing the same increased draw on my previous 2020 PP LE when I first bought it. It was 7.13kWh for the first-ever full charge. Unfortunately, I did not drive the 2020 PP much and I did not do the full charge often enough to have more records. For comparison, my 2017 PP was averaging ~6.5kWh/full charge over 3 years of my ownership, never over 7kWh. There was speculation that traction battery that has not been charged for a long time or for the first time charging, there is some "conditioning" that happens to during the charge session which may increase the total kWh used. That may true in these cases.

Anyways, before I had a chance to drive my brand new PP on EV mode, my wife took it to an out-of-town veterinary visit today. I know it will have no EV range left when she is back. The vet is almost 50 miles away. I forgot to ask her to keep a record of how far she drove the car on EV mode so I won't know the actual EV range, but I will charge it again tonight to see how much kWh the battery will take.

 

So you broke down and got another one! Congrats. I have never seen over 7 KWh on a charge. WOW. It'd be interesting to see how quickly it drops. You might be onto something with the conditioning part.

I should charge mine one of these days on the L1 charger with the Killawatt to see how it compares to L2.

 

6.25 kWh is the max using L2 for our 2 Prime from 2017 and that's with climate load while charging. The usual has been 5.75 kWh for years and still is.

We have anecdotally observed that Toyota pushed SOC limits in UX300e and apparently RAV4 Prime. So, the idea of the same for Prius Prime is not much of a reach.

 

Here is the second full charge result from last night. Still over 7kWh. DW said yesterday our new PP with a full charge on its very first EV mode virgin voyage, it drove ~30miles before running out of the charge. GOM this morning after the second full charge was showing 24.1miles without AC.

 

I think that 5.8-6.0 kwh is just about the most anyone gets with L2 (240v) charging. But for L1 (120v) charging, the maximum is between 6 and 7 kwh. I think that the difference is the doubled time of the overhead of the charger, such as the cooling fans and charger electronics.

 

Here is the result of the third full charge on 4 days old 2021 PP. This time it is down a bit to 6.85kWh, but still higher than most of the full charges I have seen in the past. And my DW who drove my PP two days in a row for out-of-town trips, claims the second full charge carried the car 34 miles on EV mode before depleting the charge.



Just checked the record of a full charge on my previous two PPs.

For 2020 PP, I did full charge only 5 times during the 10 months I owned it. The numbers were as follows.

7.13
6.77
6.92
6.72
6.94
The average was 6.90kWh (n=5)

For 2017 PP, I did many more full charges during 2.5 years of ownership. Basically doing overnight full charge every working day for most of the ownership, so that would be 5/week times 130weeks = about 650 full charge sessions. My monthly average value for the kWh/ full-charge varied from the highest of 6.84kWh to the lowest of 6.32kWh with
an overall average of 6.53kWh (n=650).

The charges are all without climate preconditioning and battery cooling, but for the winter months, there may have been days when the traction battery heater that has come on and added some loads. Still, the 2017 Prime never had a full charge session that was above 7kWh even during winter, whereas for 2020 PP the very first charge was 7.13kWh, and now on my new 2021, I saw two full charges 7.15kWh and 7.03kWh. BTW, they are all by OEM L1 120v EVSE and kWh recorded by the same kill-a-watt meter I have been using last 3+ years. Now, I really think as @john1701a pointed out that Toyota may have pushed SOC limits on 2020 and newer PPs.

The next step is to check the traction battery SoC using Hybrid Assistant to see if the upper and lower limit of the SoC has changed from 2017 PP. In 2017, it was very consistently showing the upper limit at 83-84% and the lower limit at 11-14% of true SoC corresponding to the 100% SoC and 0% SoC on the dash. I never checked this on my 2020 PP, so if the limit has been widened in 2021, I may see the true SoC on HA slightly higher on 100% or slightly lower on 0% or both.

 

wait - folks complaining the Prime's warranty is silent on capacity loss (other than to say, "it's normal") - and yet wording says 10 years .... but even if (for example) you can show 50% cell loss across the board) and it's year 7, & you only have 1/2 your range? To bad? But your worry is about BEV's? Not the prime warranty?

Some bev's have warranties clearly stating no more than 20% capacity loss after 100,000 miles / 10yrs. So if you have 320 mile BEV range ... your warranty @ 100,000 still means you've got a range of over 255 miles. If not, your warranty should be honored. Range anxiety ought better be focused on any company warranty with an illusory statement of 10 years - and yet it means any range is still honkie-dorie.
.

 

The list would be nice. But again, I have no intention of keeping PHEV or BEV for 10+ years knowing the technology would be so much more advanced in that span of period.