Battery Degradation / Extended Charge

[atzmark]

Shortly after I purchased my RAV4 2/17, I discovered that my GOM range was 70 miles, with regular or extended charge.
Members here said that that was normal, as the battery had degraded that much in three years & extended range would no add any range.
Now, almost four years later, my average GOM range is 75 miles.
It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years. I was expecting the loss to be somewhat linear, rather than gaining 5 miles of range.
No loss of range in the last three years, and such a large degradation the first three years seems seems odd.
Is it possible my charging system is not working in the extended mode?
Thanks, Mark

 

[alflash]

Shortly after I purchased my RAV4 2/17, I discovered that my GOM range was 70 miles, with regular or extended charge.
Members here said that that was normal, as the battery had degraded that much in three years & extended range would no add any range.
Now, almost four years later, my average GOM range is 75 miles.
It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years. I was expecting the loss to be somewhat linear, rather than gaining 5 miles of range.
No loss of range in the last three years, and such a large degradation the first three years seems seems odd.
Is it possible my charging system is not working in the extended mode?

Check the expected mileage after full charging, before starting which, disconnect for 5 minutes the 12 volt battery.

 

[atzmark]

Alflash - Thanks for your reply. It appears your file shows information from the Toyota Techstream diagnostics.

Early on, the car was taken to Oxnard Toyota twice. Both times a "health check" was done. I was told there was no other diagnostic available for the car, there was no way to measure the capacity of the battery.

Basically, I was told there was no such thing as Toyota Techstream software, and the ONLY diagnostic for a RAV4 EV was the go/no go results of the "health check".

Since then, thanks to this forum and others, I've learned that is not true.

Any ideas on how to deal with this situation?

Thanks, Mark

 

[alflash]

Alflash - Thanks for your reply. It appears your file shows information from the Toyota Techstream diagnostics.
Early on, the car was taken to Oxnard Toyota twice. Both times a "health check" was done. I was told there was no other diagnostic available for the car, there was no way to measure the capacity of the battery.
Basically, I was told there was no such thing as Toyota Techstream software, and the ONLY diagnostic for a RAV4 EV was the go/no go results of the "health check".
Since then, thanks to this forum and others, I've learned that is not true.
Any ideas on how to deal with this situation?
Thanks, Mark

Ok, Mark.
Have you tried to do what is recommended above?

The dealer service station can, must make diagnostics using this program*

 

[atzmark]

Didn't see a reply button, so..

Unhooked the battery, got 123 mile range.

Thanks Alflash -

I'll do the battery disconnect as you described in the next day or two and get back to you with the results.

Both times when the car came back from the dealer, the range was 127 & 129 miles. Same when I replaced the 12 volt battery. Then it would decrease over a week or two to a max range of 65-70 miles, even with extended charge.

Remote diagnostics would be great. I purchased Techstream software and a Mini-Vci J2534 cable (Ebay), but the installation was beyond my skills. Plus I doubted my ability to even use/understand the program.

Thanks again for your help. The motor whine is getting louder, so when I take in in again, having diagnostic results would be great.

Mark

 

[alflash]

Didn't see a reply button, so..
Unhooked the battery, got 123 mile range.
Thanks Alflash -
I'll do the battery disconnect as you described in the next day or two and get back to you with the results.
Both times when the car came back from the dealer, the range was 127 & 129 miles. Same when I replaced the 12 volt battery. Then it would decrease over a week or two to a max range of 65-70 miles, even with extended charge.
Remote diagnostics would be great. I purchased Techstream software and a Mini-Vci J2534 cable (Ebay), but the installation was beyond my skills. Plus I doubted my ability to even use/understand the program.
Thanks again for your help. The motor whine is getting louder, so when I take in in again, having diagnostic results would be great.
Mark

The "range" you are talking about takes into account not only the condition of the battery, but also your driving style.
Show such data about the economy of your movement

MY of yours Car (maybe better VIN-code in p.m.)?

 

[atzmark]

Alflash - Great info.

2013 Year
Vin 2T3YL4DV5DW001654

I've learned the GOM is just that...80+ mph doesn't get me a lot of range.

Thanks again for your help. Mark

 

[asavage]

80+ MPH won't get you a lot of range in a gasoline or diesel vehicle, either.

It takes a LOT more energy to push a shoebox at 80 than 60. I'd say the GOM is giving you reasonably accurate information, if you routinely drive around 80.

 

[atzmark]

Thanks for your reply Al. Great reply to my last post.

One of the frustrating things about this board is that you can ask a specific question, and you get lots of answers that don't address or answer the question.

My original post ask this question: "It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years. I was expecting the loss to be somewhat linear, rather than gaining 5 miles of range."

No one has answered the question. I thought that the the degradation stopping for three years might indicate a charging problem.

Any answers to the above question would be appreciated.

Thanks, Mark

 

[asavage]

Shortly after I purchased my RAV4 2/17, I discovered that my GOM range was 70 miles, with regular or extended charge.
Members here said that that was normal, as the battery had degraded that much in three years & extended range would no add any range.
Now, almost four years later, my average GOM range is 75 miles.
It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years.

I think there's two questions there.

1) Extended Charge selection adds no range to the GOM
Assuming that the headroom of the battery when new -- that is, the amount of battery that was not being used, the unused capacity held in reserve, unable to be used -- was 20 miles or 7kWh or whatever (there's a more accurate number, but I didn't buy my RAV4 EV new and I'm too lazy to look it up), and assuming that the Extended Charge allowed one to use say 15 miles of that headroom . . .

As the battery wears/degrades, the software hides this from us by showing us the same 15+ miles for an Extended Charge, until wear = the headroom above Extended Charge (15 miles in my above example).

Using my WAG numbers above, the battery capacity would only have to be reduced by 5 miles (2kWh?) before Extended Charge starts to yield less & less. At 20 miles (7kWh?) there is no difference between Normal & Extended because the BMS won't allow a higher charge. That's where you were sometime after Feb2017, when the vehicle was n years old and had nnk miles on it. Not knowing how many miles, it would be a bad guess as to whether this was normal for your battery pack at that time.

2) Battery degrades at uneven rate (as extrapolated by the GOM numbers)

It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years.

I don't know the conditions under which the vehicle was operated before you got it, but there are ways to accelerate battery wear. You may be treating it better, and the result is a lower rate of wear. Impossible for anyone to know from this side of the screen, and I think that's why you're not getting a concretely worded reply to your question.

--------------------------------------

My own experience so far: bought a 2014 used with 49k in Aug2017 (three years ago). Drove 15k/year commuting, a mix of low and high (65 MPH) driving. No noticeable diminishment of GOM mileage guess from 49k to ~79k, when I had a battery pack (contactor) failure, and the pack was replaced. New pack has around 10k on it, and started out around 10 miles less range, which has not changed in the past ten months. It's at 90k now.

That's only one data point, but I would not be surprised to hear others have similar experiences. These packs are durable -- in a convo with Tony, he said he'd never seen a bad cell in a RAV4 pack, and he works on a lot of 'em. Contactors, yes, common issue, but not cells.

HTH

[later: Oh, non-specific replies to questions is par -- normal -- for all internet discussion boards. Frustrating, but normal. You can't do anything about it, unless you become a Moderator. BTDT, and it's generally unrewarding. The URL in my sig is my own board, where I am Gawd, when I choose to exercise the effort.]

[still later]
Information on Tesla battery pack wear rates, going back years:
https://electrek.co/2020/06/12/tesla-data-battery-degradation-limited-mileage-packs-equal/

 

[miimura]

Using the GOM to estimate anything is meaningless unless you have the computer reset the mi/kWh used for display. Then you can use it to compare the usable capacity from one time to another. The simplest way to reset the mi/kWh is to disconnect the 12V battery. However, the usable energy reported by the BMS also varies with temperature and time since charging if it is balancing the battery.

As the battery degrades, the Extended Charge energy will gradually reduce until it doesn't add any energy to the battery beyond the Standard Charge. This is because Toyota wanted the Standard charge to represent a constant amount of energy. As the battery ages and degrades, the Standard Charge will charge up to a gradually increasing percentage of usable energy in the battery pack. Once the Standard Charge reaches 100% of the usable energy, the Extended Charge setting won't do anything.

Long story short, it's very unlikely that the battery would degrade 20% in the first three years and then not at all in the following three years. It's more likely that your understanding of the actual battery degradation over time was inaccurate.

 

[smkettner]

One of the frustrating things about this board is that you can ask a specific question, and you get lots of answers that don't address or answer the question.

My original post ask this question: "It seems odd that the battery would degrade 20% in the first three years, and not at all the following three years. I was expecting the loss to be somewhat linear, rather than gaining 5 miles of range."

No one has answered the question. I thought that the the degradation stopping for three years might indicate a charging problem.

Any answers to the above question would be appreciated.

Thanks, Mark

Yes lithium degrades on a curve. Fast at first and then it slows down. This includes several factors including usage, time, heat, average charge level and probably more. The fact that the curve has flattened is actually expected. This is a battery, not brake shoes.

I really expect the 5 miles gained is based on your current driving style, general driving conditions and temperature as the primary factors. The 5 miles gained does not reflect actual battery capacity change. DTE meter changes based on conditions and is an estimate of range only not a battery capacity meter as then it would read energy units not miles.

 

[atzmark]

Thanks all for the info on battery degradation. This my understanding of the several responses:

I shouldn't complain that my 7 year old 60K mile EV still gets 65-75 GOM (& actual) range. I rarely drive more than 25 miles a day, so who cares what the GOM says.

Like taking my blood pressure, I can "feel" when I using a lot of juice (85mph+ freeway, love the Sport button!) and my internal GOM adjusts the range pretty accurately.

I don't know how the first 35k miles were charged/driven; I drive hard, short runs.

While a declining capacity curve is the norm, the 3 year curve & followed 3 year flat line is uncommon, regardless of prior & current use & driving style.

Most likely my charging system is fine.

As the motor whine gets louder, I'll bring the car in for replacement (under warranty) and hopefully get a Techstream or Tesla diagnostic readout having some battery capacity info.

Thanks again to all. I think we can put this thread "to bed". Really appreciate all the responses & info.

Mark

 

[alflash]

... As the motor whine gets louder, I'll bring the car in for replacement (under warranty) and hopefully get a Techstream or Tesla diagnostic readout having some battery capacity info.
...

You can know, for example,

Do you have a record of sound of motor whine?

 

[atzmark]

No recording.

Seems I would have to put the car on a lift and get some recording equipment.
Or I would hang out the door and hold the cell phone under while moving (sounds scary).

Any info on how to get a recording of the motor noise would be appreciated.

Mark

 

[alflash]

No recording.
Seems I would have to put the car on a lift and get some recording equipment.
Or I would hang out the door and hold the cell phone under while moving (sounds scary).
Any info on how to get a recording of the motor noise would be appreciated.
Mark

For example (without a sound finders),
https://youtu.be/dEYsYZo8Oz8

 

[Syrinx]

Alflash - Great info.

2013 Year
Vin 2T3YL4DV5DW001654

I've learned the GOM is just that...80+ mph doesn't get me a lot of range.

Thanks again for your help. Mark

Unrelated to your original post, but thought it a fun coincidence that yours came off the line right before mine did (VIN 1655).

 

[alflash]

Alflash - Great info.
2013 Year
Vin 2T3YL4DV5DW001654
I've learned the GOM is just that...80+ mph doesn't get me a lot of range.
Thanks again for your help. Mark

Unrelated to your original post, but thought it a fun coincidence that yours came off the line right before mine did (VIN 1655).

1655: ... (VIN n/a)
1654: Production Date: 04/08/2013, Date of First Use: 10/22/2013, Exterior Color: 08V5, SHORELINE BLUE PEARL