Seeking “hole in the wall” restaurants in CM for home-style farang food

[JBChiangRai]

There is a YouTube video posted on one of these forums by Engineering Explained that explains the chemistry of LFP and how to get the longest life out of your batteries.

 

He explains what Tesla say for their LFP batteries and he goes through why they recommend that. He also goes through what Ford say.

 

Typically, manufacturers suggest you charge to 100% and run down the battery to less than 20% and then recharge.

 

The reason for doing this is to recalibrate the state of charge/range calculator. I explained earlier why it’s very difficult (read impossible) to determine the state of charge between 50% and something like 85%.

 

If you are prepared to sacrifice the accuracy of the range display, then you will get the most longevity out of your battery by keeping it  in the lowest state of charge possible but above 0%. 
 

If you do this, your range remaining indication is not accurate and it gets worse as time goes by, it’s only reset by charging to 100% and the batteries actual capacity cannot be determined until you go below 10%.

 

The chemistry is clear and cannot be disputed.

[JBChiangRai]

This is the video, there are 4 or 5 recommendations, there is no shortcut but to watch the video.

 

He explains the chemistry and he explains why he gives the recommendation.

 

this is specific for LFP chemistry and does not apply to NMC.

 

 

[Pib]

Edit:  durn....I was still typing out my long winded post talking the same video JB posted above....passing in the night....didn't see he has posted the video just minutes below until after I posted my post.

 

A pretty good 18 minute video on EV LFP  NMC/NCA battery charging from several standpoints of EV usage and battery life.  And it even talks that recent study talking how always keeping your LFP charged to a high level might be detrimental to its life span...and this guy points out that recent study acknowledges another recent study indicates keeping the EV LFP highly cared (except for extended storage/non use of months) does "not" affect the LFP battery lifespan.    

 

And for those listening-in don't confuse Lithium NMC/NCA EV batteries with Lithium LFP batteries....two different battery chemistries with two different best care & charging practices.

 

For Lithium NMC/NCA type batteries  EV manufacturers recommend only charging to 80% except when you need to take a long trip and want to start off with max range at 100% charge. 

 

Whereas Lithium LFP type batteries EV manufacturers recommend a weekly-to-monthly charge to 100% to recalibrate the charge percentage indicator and every 3 to 6 months letting the battery drop to 10% and recharging to 100% which accomplishes a full recalibration of the charge percentage indicator.

 

 

 

Edited 2 hours ago by Pib

[JBChiangRai]

To be clear.

 

Regarding BYD LFP cars…

 

Charging to 100% calibrates the 100% SoC level.

 

Discharging below 10% tells the car what the capacity of the battery is (ie what SoH is).

 

The cars BMS uses 2 techniques to determine both SoC and SoH.  The first is Coulomb counting (this gets less and less accurate until it’s recalibrated by discharging below 10% followed by recharging) and secondly achieving peak voltage which tells the BMS the SoC is 100%.

 

Charging to 100% does not tell the BMS the capacity of the battery.  Measuring coulombs from 100% SoC to less than 10% or recharging from below 10% to 100% allows the BMS to measure the Coulombs and determine SoH.

[Pib]

15 minutes ago, JBChiangRai said:

 

If you are prepared to sacrifice the accuracy of the range display, then you will get the most longevity out of your battery by keeping it  in the lowest state of charge possible but above 0%. 

Question: I haven't see in any of these reports/studies giving specifics examples of "how much more longevity" really is.   Is it another 100,000km...is it another 2 years?  And the studies/reports also talk the EV battery is going to probably last a long time even if DC Fast Charging all the time.   It's like it's probably detrimental but we really can give specific numbers as to how many less Km's/less years of life that means. 

 

Unless a person plans on keeping the EV well past the battery's warranty period like for example BYD's battery warranty period of  8 years/160,000Km (whichever comes first).   And where I saw "....well past..." I mean a person is shooting for say 15 years/300,000Km then i really can't see babying the battery, doing more frequent charging because a person keeps the EV well below 100% charge, etc.  

[Andrew Dwyer]

13 minutes ago, Pib said: 

 

Whereas Lithium LFP type batteries EV manufacturers recommend a weekly-to-monthly charge to 100% to recalibrate the charge percentage indicator and every 3 to 6 months letting the battery drop to 10% and recharging to 100% which accomplishes a full recalibration of the charge percentage indicator.

 

 

 

I will watch the video, but a quick question.

 

I see some people stating that the 10% to 100% charge should be done at a slow charging speed, i.e. AC, to effectively achieve battery balancing, is that true ?

[JBChiangRai]

6 minutes ago, Pib said:

Question: I haven't see in any of these reports/studies giving specifics examples of "how much more longevity" really is.   Is it another 100,000km...is it another 2 years?  And the studies/reports also talk the EV battery is going to probably last a long time even if DC Fast Charging all the time.   It's like it's probably detrimental but we really can give specific numbers as to how many less Km's/less years of life that means. 

 

Unless a person plans on keeping the EV well past the battery's warranty period like for example BYD's battery warranty period of  8 years/160,000Km (whichever comes first).   And where I saw "....well past..." I mean a person is shooting for say 15 years/300,000Km then i really can't see babying the battery, doing more frequent charging because a person keeps the EV well below 100% charge, etc.  

 

I don’t know by what percentage this makes a difference.

 

He also covers in passing that temperature has a significant effect. I would be interested to know by how much temperature makes a difference.

 

My garage is air-conditioned, but I only tend to turn it on when charging, and we have a significant surplus in solar power.

 

We have 18 kW of grid-tied inverters and it’s very difficult to output more than maybe 8 or 9 kW, charging the car when it’s sunny, allows me to get the full output power of the inverters, but not always, we still derate to 12 kW sometimes.

Edited 1 hour ago by JBChiangRai
Spelling

[Pib]

13 minutes ago, Andrew Dwyer said:

I will watch the video, but a quick question.

 

I see some people stating that the 10% to 100% charge should be done at a slow charging speed, i.e. AC, to effectively achieve battery balancing, is that true ?

 

I don't know....I've seen that in other forums like on reddit from everyday folks like myself...but I've never seen any of those posts provide some reference from the EV manufacturers.....like a quote from the EV manual, some EV technical/specifications document.    

 

Personally, I think it probably would provide a "little bit better balancing" due to less battery heating & stress and giving the BMS more time of around 9 to 10 hours to fully recharge with a 7KWH wall charger compared to around 1 hour with a DC Fast Charger.  And don't ask what a "little bit better balancing" means in specifics as I don't know.....just like battery studies/reports that don't give specifics on just how many more or less years/kilometers a battery might last if Fast or Slow charged.

Edited 1 hour ago by Pib

[JBChiangRai]

11 minutes ago, Andrew Dwyer said:

I will watch the video, but a quick question.

 

I see some people stating that the 10% to 100% charge should be done at a slow charging speed, i.e. AC, to effectively achieve battery balancing, is that true ?

Sorry, you didn’t address this to me, but I will jump in if that’s OK.

 

I am fairly sure BYD use active balancing, the BMS is balancing the cells all the time so speed of charging probably won’t affect that process, other than it may not have finished balancing the cells for some considerable time after finishing charging.

 

For those cars that have passive , balancing, typically MG, then the balancing occurs at the end of the AC charge cycle. The system uses a system of resistors and wastes a little energy as it brings all the batteries to 100%. Individual cells either take more charge or blow off the excess power through resistors generating heat.
 

When I built the LFP battery pack for my solar power, I added active balancers. I did that specifically because I didn’t want to ever charge them past 80% unless notified of a power cut if I had allowed passive balancing then they would never have balanced because I never charged them to 100%.

Edited 1 hour ago by JBChiangRai
Correct dictation errors

[Pib]

Here's what the BYD Atto manual recommends for SOC recalibration and also if not using the EV for over one week.

 

[JBChiangRai]

2 minutes ago, Pib said:

Here's what the BYD Atto manual recommends for SOC recalibration and also if not using the EV for over one week.

 

Again, watch the video if you want to know why they recommend this.

 

This will not give you the maximum battery life.

[JBChiangRai]

What you do is a compromise.

 

Maximum battery longevity is achieved through inaccurate range display.

 

Accurate range display will not achieve maximum battery longevity.

 

So you have to decide which you want. You can have one or the other, but you cannot have both.

[Pib]

10 minutes ago, JBChiangRai said:

Again, watch the video if you want to know why they recommend this.

 

This will not give you the maximum battery life.

I did watch it....I understand what this study says can be the detrimental effects....effects with no "specific metrics" as to how much degradation may be caused such as reducing battery life span from say 15 years to 12 years....reducing battery Km life span from 400,000 to 350,000, etc. 

 

 And at the the 17 minute point of the 18 minute video the guys says the study he primarily talked admits another study has different results that there is more battery capcity fade if consistently keeping the LFP battery charged to lower levels as compared to higher levels.  Which study do you believe.   And regardless of which study is correct it sure would be nice if the studies gave some "specific metrics" as to what the typical EV driver should expect in terms of less or more battery life after X-amount of years/kilometers.

 

 

 

[JBChiangRai]

1 minute ago, Pib said:

I did watch it....I understand what this study says can be the detrimental effects....effects with no "specific metrics" as to how much degradation may be caused such as reducing battery life span from say 15 years to 12 years....reducing battery Km life span from 400,000 to 350,000, etc. 

 

 And at the the 17 minute point of the 18 minute video the guys says the study he primarily talked admits another study has different results that there is more battery capcity fade if consistently keeping the LFP battery charged to lower levels as compared to higher levels.  Which study do you believe.   And regardless of which study is correct it sure would be nice if the studies gave some "specific metrics" as to what the typical EV driver should expect in terms of less or more battery life after X-amount of years/kilometers.

 

 

 

I agree with you, it didn’t go far enough by explaining how large the effect was.

 

I tend to believe what the Tesla Guru says and that higher state of charge is detrimental. It’s what I’ve also read on battery university.  EE does explain the chemistry behind this and it make sense.

 

Generally, I find EE quite good, he spent almost 18 minutes explaining why a high charge state degrades the battery and only a few seconds saying there’s one study that contradicts this.

 

It’s easy for me to keep my SoC low because most of my journeys are 10 to 30 km, I only go to Chiang Mai occasionally and only once further than that in the last five years.

 

Until I watch that video, I used to keep SoC between 80 and 100%, I don’t do that anymore.

[mistral53]

1 hour ago, Gweiloman said:

What’s other BYD owners take on this? Are you following the above “recommendation”? I’m usually charging from 20% or less every couple days but not always to 100%.

 

Is the battery affected detrimentally if we don’t follow the above strictly?

I talked to the GM of a BYD dealership the other day and mentioned the importance of charging to 100% and all - he chuckled and said 'oh - you are one that goes by the book, I just charge to 100% every day, I cant be bothered'. Of course, for him its an expense he does not pay for and he will dump his car to an unsuspecting buyer every few month, but it made me think....... is it really worth stressing over? 

 

I have always been the kind of idiot taking great care of my cars........ for the next guy! But what's he point, really? I have almost never had a car for more than 3, 5 years at the most. And cars start to feel more and more like smart phones - I want the latest goodies and tiny incremental performance gain, tell me what is new! tell me we need it! tell me it makes me happy for a split moment........

 

Damn this Cabernet tastes good, fill her up again.......