EV only Range after nearly 4 years... where you guys at?

[ClarityBill]

But do you think it might be good for the battery to do this occasionally? I have never dropped mine below 2 bars in 4.5 years, might that not contribute to reduced battery capacity? My understanding of the way to do this is to drive slowly when EV gets near 0 until the engine comes on, then go up to highway speeds with the AC on to suck battery energy while the engine warms up enough to recharge.

That is the way that I did it... EV 0, engine just turning on to go to highway speed. I also have a significant hill to climb just after I get on the highway.

Everybody has an opinion... I think I damaged my battery when I was doing this about twice a week for a couple months. I was also charging my battery at 240v and 32A. My battery is still pretty good, but my impression was my battery degraded especially during that time.

 

[Landshark]

But do you think it might be good for the battery to do this occasionally? I have never dropped mine below 2 bars in 4.5 years, might that not contribute to reduced battery capacity?

I’ll take this one.

No.
No.

 

[David Towle]

I’ll take this one.

No.
No.

Landshark as usual you are very clear. But do you have any references to point to?
My only reference is I remember my electric toothbrush said to run it all the way down before recharging. And of course that is irrelevant here.

 

[David Towle]

That is the way that I did it... EV 0, engine just turning on to go to highway speed. I also have a significant hill to climb just after I get on the highway.

Everybody has an opinion... I think I damaged my battery when I was doing this about twice a week for a couple months. I was also charging my battery at 240v and 32A. My battery is still pretty good, but my impression was my battery degraded especially during that time.

I use the lowest amp 240 volt charger I could find, 16 amps, because of the small size of the Clarity battery.
Its plenty fast for my use.
And cheaper than larger chargers.

 

[Landshark]

The 17 KW battery has buffers at top and bottom that cannot be used. These buffers are to protect the battery. The bottom buffer varies with use. If you use a car scanner (OBDII) to read the battery level, the car is at 0 EV miles when battery shows 11% remaining charge. If you continue to drive, the engine will start, but the battery level will control about 7.5% actual charge. The battery meter on the dash will be at 2 bars until the actual charge gets to about 2%, and drops to one bar. Battery meter drops to no bars right around zero real charge.

What SOC percent does the OBDII device display when the battery is “fully” charged and the battery gauge shows all 20 bars?

The reason for this question is that we know that the charging protocol does not allow for the battery to accept a charge to 100% SOC. Targeted charging voltage per cell is 4.09x. A fully charged 3.7V cell needs to reach 4.2V to be at 100% SOC. The targeted voltage charges the battery to approximately 90% SOC.

We have been presented with precise numbers, such as 11%, 7.5%, 2% and zero, in conjunction with the term “real charge”, however, if the device is not providing an accurate number for a “fully” charged battery, it can’t be trusted to provide accurate numbers elsewhere.

In all likelihood, the 0-100% SOC reported from the device is actually 10-90% of true SOC. When the battery stops providing energy, it has reached a cut-off voltage that was determined by the engineers.

 

[Landshark]

Landshark as usual you are very clear. But do you have any references to point to?
My only reference is I remember my electric toothbrush said to run it all the way down before recharging. And of course that is irrelevant here.

I’ll kindly request that you research Lithium battery chemistry on your own. As an engineer you will quickly discover the factors that determine battery longevity.

I use the lowest amp 240 volt charger I could find, 16 amps, because of the small size of the Clarity battery.

Spoiler Alert: Level 2 charging the Clarity at ~30A is not one of those factors.

 

[PHEVDave]

I’ll kindly request that you research Lithium battery chemistry on your own. As an engineer you will quickly discover the factors that determine battery longevity.



Spoiler Alert: Level 2 charging the Clarity at ~30A is not one of those factors.

I would agree. The charging rate at ~30A is probably no greater than most cellphones or other portable devices using Lithium batteries. Also, the advice to fully discharge an electric toothbrush probably dates back to the usage of Ni-Cad batteries. If they didn’t get deeply discharged now and then they would develop a sort of “memory” that would reduce the amount of charge they would hold. The new Lithium batteries generally don’t have that problem.

 

[Landshark]

As an engineer you will quickly discover the factors that determine battery longevity.

Spoiler Alert: Level 2 charging the Clarity at ~30A is not one of those factors.

This should have been worded differently. Perhaps, “… factors that contribute to battery degradation”. And, “… not a significant factor”, would have been more clear.

Using a battery causes it to degrade. When used as designed, it will tend to degrade as expected.

 

[David Towle]

This article seems to cover the basics: https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries
However the differences in narrow versus wide cycles are not as extreme as the graphs appear to show. They should not be plotting different charge scenarios against battery cycles, they should be plotted against total charging energy. With narrower charging you need more cycles.
Based on this, there's nothing I can do to improve the life of my Clarity battery. However, in everyday use on my Tesla I will switch from my current 30-70% range to 50-65%. Basically switching from charging every 4 days to every 2.
Charging at lower 16 amp rates has no disadvantages, the charger is much cheaper, and it came with the longer cord I needed to fit my garage outlet placement.

 

[Landshark]

Based on this, there's nothing I can do to improve the life of my Clarity battery. However, in everyday use on my Tesla I will switch from my current 30-70% range to 50-65%. Basically switching from charging every 4 days to every 2.
Charging at lower 16 amp rates has no disadvantages, the charger is much cheaper, and it came with the longer cord I needed to fit my garage outlet placement.

Does this mean that you won’t be intentionally discharging the Clarity battery to 1 or zero bars?

What is the desired outcome of the new charging regime? Is it to obtain 10,000 shallow charge cycles over the next 65 years in order to maintain 70-80% of the original battery capacity?

One disadvantage with a 16A EVSE is a slower charge rate than a 30-32A device. This may never be an issue for some. I never thought it would be. For the first 2 years with the Clarity it was almost always charged with the OEM L1 EVSE. This was never a problem. I got home from work and the car could charge for 10-12 hours. Now, in retirement, with 2 PHEV’s, there have been numerous times where the faster charging L2 device has been a great convenience. Sure, the higher amperage device may cost a bit more upfront, but a relatively quick charge allows us to travel using cheap electrons rather than expensive gasoline.

As far as battery degradation goes, there is no advantage or disadvantage to either.

 

[David Towle]

Does this mean that you won’t be intentionally discharging the Clarity battery to 1 or zero bars?

What is the desired outcome of the new charging regime? Is it to obtain 10,000 shallow charge cycles over the next 65 years in order to maintain 70-80% of the original battery capacity?.

Hahaha. Its no effort to change the normal (90% of the time) charging plan to improve the battery life so why not do it?

BTW I have a 42 amp charger for the Tesla but I use the Tesla app to dial it down to 30 amps. It gets too hot at 42 and sometimes trips out.

 

[Landshark]

Hahaha. Its no effort to change the normal (90% of the time) charging plan to improve the battery life so why not do it?

BTW I have a 42 amp charger for the Tesla but I use the Tesla app to dial it down to 30 amps. It gets too hot at 42 and sometimes trips out.

Cell balancing occurs near the end of a full charge cycle. It’s a necessary process to maintain a health battery. One bad cell typically leads to a replacement of the entire battery module.

What is the Amp rating of the breaker that is protecting the circuit for the 42A EVSE? Is the breaker located in a panel that is outside and/or exposed to direct sunlight?

 

[David Towle]

Cell balancing occurs near the end of a full charge cycle. It’s a necessary process to maintain a health battery. One bad cell typically leads to a replacement of the entire battery module.

What is the Amp rating of the breaker that is protecting the circuit for the 42A EVSE? Is the breaker located in a panel that is outside and/or exposed to direct sunlight?

So you are saying I should occasionally charge to 100% right? We do every few months when we have a long drive.

No its not the breaker, its the charger itself that goes into error mode and stops charging. Its a cheap brand (Splitvolt) that came with our new house. The Tesla app makes it quite usable, with the VW we had previously it was a hassle as it tripped out regularly, the VW had no way to control the amperage.

FYI both of our charging circuits are on 50 amp breakers in the garage.

 

[Landshark]

So you are saying I should occasionally charge to 100% right?

No. I am not saying that. I’m am simply informing you of when cell balancing occurs.
Does every few months meet your definition of occasionally? Honda recommends to fully charge the Clarity battery prior to each use. That recommendation could be for any number of reasons. Nowhere in the manual is it recommended to operate with the battery between specific SOC percentages.
Are you comfortable operating with cells out of balance for a few months? Do you intend to monitor cell voltages on a daily basis? What you are doing is micromanaging the battery on certain peramiters while failing to consider the potential impacts of those decisions. What sort of life expectancy are you trying to achieve from these batteries?

No it’s not the breaker, it’s the charger itself that goes into error mode and stops charging. It’s a cheap brand (Splitvolt) that came with our new house. The Tesla app makes it quite usable, with the VW we had previously it was a hassle as it tripped out regularly, the VW had no way to control the amperage.

FYI both of our charging circuits are on 50 amp breakers in the garage.

Per NEC Code, a 50A breaker is sized for a continuous load of 40A. A 60A breaker is sized for a continuous load of 48A. A 42A EVSE should be on a dedicated circuit that is protected by a 60A breaker, and of equal importance, the wiring should be of the appropriate type and gauge.

One possibility is that the high load may have caused a drop in line voltage that was significant enough to cause the device to shut down as a means of protecting itself. Amperage increases as voltage drops.

 

[David Towle]

No. I am not saying that. I’m am simply informing you of when cell balancing occurs.
Does every few months meet your definition of occasionally? Honda recommends to fully charge the Clarity battery prior to each use. That recommendation could be for any number of reasons. Nowhere in the manual is it recommended to operate with the battery between specific SOC percentages.
Are you comfortable operating with cells out of balance for a few months? Do you intend to monitor cell voltages on a daily basis? What you are doing is micromanaging the battery on certain peramiters while failing to consider the potential impacts of those decisions. What sort of life expectancy are you trying to achieve from these batteries?

Per NEC Code, a 50A breaker is sized for a continuous load of 40A. A 60A breaker is sized for a continuous load of 48A. A 42A EVSE should be on a dedicated circuit that is protected by a 60A breaker, and of equal importance, the wiring should be of the appropriate type and gauge.

One possibility is that the high load may have caused a drop in line voltage that was significant enough to cause the device to shut down as a means of protecting itself. Amperage increases as voltage drops.

As I stated, I was not talking about the Honda, it goes to 100% every day or 2 when I charge it. Tesla's delivery guy recommendation was to use it between 30% and 70% for normal use. Official Tesla instructions just say don't go to more than 90% for daily use. I was looking at the recommendations in the article I posted to come up with the best for battery life for the Tesla, doing that would make no sense on a limited range PHEV.

The Tesla app software shows up to 42 amp, but I looked at the charger itself and its actual rating is 40 amps, correct for our 50 amp circuits.

 

[Landshark]

I was looking at the recommendations in the article I posted to come up with the best for battery life for the Tesla, doing that would make no sense on a limited range PHEV.

The question remains about cell balancing.

Are the Tesla batteries so delicate that they need to be operated within a SOC range of 30-70%, or an even narrower range of 50-65% in order to provide a reasonable life cycle?

These aren’t button batteries for cell phones. They are designed for motive power and energy storage. Many manufacturers have tested them to show that they deliver thousands of deep charge cycles and will still retain 70-80% of their original capacity.

I understand that what you are doing is easy to program. You’ll probably be able to donate some healthy batteries to a museum in 40-50 years. They’ll last even longer if you don’t use them at all.

Best of luck.

 

[David Towle]

I generally keep cars a long time. Best for me was 25 years/ 290,000 miles (I drive a lot more annual miles now in retirement) with a 1987 Peugeot 505. I want to do better in the future. Car still viable when I am in the ground equals good.

Here's a more detailed paper I found and have only begun to read,
https://mediatum.ub.tum.de/doc/1355829/document.pdf

 

[Landshark]

I generally keep cars a long time. Best for me was 25 years/ 290,000 miles (I drive a lot more annual miles now in retirement) with a 1987 Peugeot 505. I want to do better in the future. Car still viable when I am in the ground equals good.

That’s an admirable goal. The Magic 8-Ball indicates “Unlikely” when asked if you will be driving the same Tesla in 20 years.

Also, be sure to identify the specific Lithium chemistry that is used in your Tesla when conducting your research.

 

[Landshark]

The charging rate at ~30A is probably no greater than most cellphones or other portable devices using Lithium batteries.

The onboard charger on the Clarity is capable of charging at a rate of approximately .4C. That means the battery is accepting 40% of its rated capacity per hour. This is a relatively slow charge rate for Lithium batteries.

The rate at which we choose to charge the battery in the Clarity will have a statistically insignificant impact on battery degradation.

 

[Donald Rapp]

So the range on my Honda Clarity is hovering around 30 miles all EV recently. I used to get 47-50 miles in the middle of summer when new. My commute has changed quite a bit, I go uphill and only drop my kid off at school, vs in the past i started out going downhill toward work.

But nearly 40% drop in EV miles since purchase feels steep. What percentage loss is warrantied before the 8 year mark? I love the car.. but hardly drive it anymore that i work from home. The EV mileage estimator may be off some because 5 days a week i'm only driving 4 miles a day sometimes. I guess i could purchase a battery life tester of some sort.. any suggestions?

There is a lot of nonsense on this forum. There are two indicators of EV mileage on the Clarity. One is the digital display in the middle of your dash that says something like 38 miles digitally. This is not (I repeat not) a reading of the battery state of charge. It is a computer generated estimate of your expected miles based on recent past driving experience, using some crazy algorithm that is obviously wrong. In my car it always underestimates true miles available by at least 5. The other is the bar chart to the left of the dash display and while this has no numbers, it seems to be a better indicator of the battery charge. I can repeatably drive with the digital display reading 0.0 and the bar chart is not zero. I recently went seven miles on EV with display showing 0.0. So, when my digital shos 40 I expect the car can go 47+ on EV.