EV Owners … Real life experience & help thread

[KhunLA]

17 minutes ago, vinny41 said:

MG updated their website 1st October

https://www.mgcars.com/th/promotions/12

It's called marketing ... good luck finding one.

 

LAZ advertises 'free shipping' also, out of 100-150 orders, might have got free shipping once  ...

... marketing 

 

MG ZS EV gets 403 kms per charge ... marketing again.

 

Edited October 20 by KhunLA

[Andrew Dwyer]

3 hours ago, richard_smith237 said:

 

There are a couple of negatives...   but they are not show stoppers.

 

 

1) There is the need for numerous different EV charging Apps ( I think about 8 in total )

... some of which requires money pre-loaded into in-app wallets.

 

2) When 'charging' at a shopping mall.

- its great if you can get a slower Type 2 AC charger that will gently top up the charge over a few hours (2-3-4 hrs etc)

- But, if you get a CCS2 DC charger that will top up the car in 20-30mins, then you have to go back and exit the charging bay and park elsewhere (which of course adds a further element of inconvenience).

 

 

 

 

 

 

 

 

1) I don’t see the fact that there are plenty of apps for charging EV’s as a negative, on the contrary. While I have downloaded a few app I only use 2 in nearly a year, 1 has no money loaded and the other does have money loaded into a wallet but it doesn’t have a minimum and I can transfer the minimum amount to it shortly before charging if necessary.

Where is the negative ?

 

2) Now it appears that charging too fast is a negative ?, just choose the AC option .

[jacob29]

10 minutes ago, JBChiangRai said:

Chinese EV's are sold in China at a realistic price, nobody thinks they are dumping product there, yet their cars are much cheaper there than Thailand which IMHO should be harmonised to that price structure.  There is no valid reason they should cost so much more here.

The vast majority of manufacturers are selling at a loss on the mainland, if it's not dumping it's still unsustainable.

[JBChiangRai]

4 minutes ago, jacob29 said:

The vast majority of manufacturers are selling at a loss on the mainland, if it's not dumping it's still unsustainable.

 

I would prefer to see some evidence of that....

[vinny41]

16 minutes ago, JBChiangRai said:

I think there is an issue with how we consider depreciation of EV's.

 

A car (to take Vinny's example) that used to cost 1,189k and now costs 599k by comparing to a purchase cost of 1,189k will have depreciated massively.  But if we compare it to the new cost of 599k then it hasn't depreciated so much.

 

I think the moment a manufacturer slashes the price of their cars, all used examples take an extra hit of depreciation.

 

Is it fair to say EV's depreciate rapidly because of that?  aren't we taking an extraordinary event to make a generalised  conclusion?

 

I think manufacturers are finding their feet regarding pricing of EV's.  Particularly the Chinese who aren't slashing their prices to survive, they are simply adjusting them to what they should be, and especially with the price of batteries falling.

 

Chinese EV's are sold in China at a realistic price, nobody thinks they are dumping product there, yet their cars are much cheaper there than Thailand which IMHO should be harmonised to that price structure.  There is no valid reason they should cost so much more here.

 

I think they entered the Thai market thinking they could make a quick killing and now that they have competition, ( mostly from each other) they are stabilising to real price and real value.

 

The big issue I think, is if China can build and sell quality EV's in China to a price, why can't the rest of the world even get remotely close to that?

 

Competition is great for the consumer, it pushes price down and quality up.

For anyone that bought a MG ZS EV in 2022 and paid the after subsidy price of B949,000

their car value is approx B485K although most MG ZS EV are being advertised for around B469K now if there was no price reductions and alllowing an annual depreciation rate of 10% per year their car should be valued at B769K

The Chinese EV Brands are reducing their prices to sell and they have a huge overstock but at the same time the price of parts are not reducing at the same level that is taking place with the price reductions on cars

For the Chinese EV manufacturers that signed up to EV 3.0 subsidy in 2022 the conditions are for every car they imported in 2022 and 2023 they are required to build on a 1 to 1 ratio in 2024 there is an allowance that states if you don't build your quota in 2024 you can carry over that quota into 2025 but the ratio changes to 1.5 Thai builds for every 1 vehicle imported if you don't hit the quota and the end of 2025 they have to repay the subsidy + fines + import duties I have seen reports where the fines range from B550K to B750K

The easiest solution would be if they were allowed for the 2023,2024 imports to be allowed to delay some of the local build into 2025/2026 on the same ratio as 2024 1 to 1 ratio

Even with B450K price reductions that is still cheaper than paying back the subsidy y + fines + import duties

Chinese EV industry in Thailand faces a crisis. It is demanding an urgent hearing from the government on its promotions

https://www.thaiexaminer.com/thai-news-foreigners/2024/10/09/chinese-ev-industry-in-thailand-faces-crisis-it-is-demanding-an-urgent-hearing-from-the-government/

[vinny41]

40 minutes ago, jacob29 said:

What practical difference does it make whether it's 700% or 900%?  It's a number massively higher than 100%, which is the point being made. It's my poor math converting 8x to 900% when it should have been 700%.

 

If there are lots of links showing 100% increases in premiums, maybe you should post those instead of an article that talks about the volume of claims.

It makes a huge difference also important to show the baseline number

if I sold one product in 2022 and then I said I increased sales by 1000% in 2023 that would mean I sold 10 products in 2023 selling 10 products not as impressive as saying sales increased by 1000%

[jacob29]

45 minutes ago, JBChiangRai said:

 

I would prefer to see some evidence of that....

https://www.scmp.com/business/china-business/article/3275699/chinese-ev-makers-losses-mount-rising-sales-fail-offset-steep-discounts

[richard_smith237]

50 minutes ago, Andrew Dwyer said:

1) I don’t see the fact that there are plenty of apps for charging EV’s as a negative, on the contrary. While I have downloaded a few app I only use 2 in nearly a year, 1 has no money loaded and the other does have money loaded into a wallet but it doesn’t have a minimum and I can transfer the minimum amount to it shortly before charging if necessary.

Where is the negative ?

 

2) Now it appears that charging too fast is a negative ?, just choose the AC option .

 

Fair point - lots of apps but we can get used to that easily enough.

 

On the second point - having to go back to the car to move it is an inconvenience.

CCS2 chargers are great… but not at the shops etc (the one I just used didn't have a Type 2 AC charger).

 

Just highlighting that EV usage / charging etc not quite the perfect world.

 

Just pulled into a PTT station with KFC - so we could charge & grab a snack…

CCS2 chargers in use.

 

Another point - scanning all those QR codes on my phone  (QR stickers on the charge machines)…. that’s a massive security risk…. Lots of warnings going about alerting to the risk of scanning ‘fraudulent’ QR codes that gives scammers access to the phone. 
 

 

 

 

 

[jacob29]

22 minutes ago, vinny41 said:

It makes a huge difference also important to show the baseline number

It's not a huge difference compared to 100%, which is the reason I  converted to percent (incorrectly) in the first place. 700% vs 100%, compared to 900% vs 100%. The point remains, that there is nothing unusual about a dramatic increase in the number of claims, considering the explosive growth in sales.

 

Baseline number is practically irrelevant, since it applies in equal measure to the number of insurance claims made (e.g. also makes your 100% increase in claim 'look impressive')

 

 

Edited October 20 by jacob29

[motdaeng]

41 minutes ago, jacob29 said:

https://www.scmp.com/business/china-business/article/3275699/chinese-ev-makers-losses-mount-rising-sales-fail-offset-steep-discounts

 

i'm not a finance expert or a business expert...

but isn't it normal for every new car company to face years of losses before making profits?

the investment costs for a startup can easily reach a few billions of dollars...

 

tesla took about 15 years to produce at a profit, and now no one talks about that as a bad business

decision ... is there a different to the chinese ev car markers?

[KhunLA]

So ... any " Real Life Experiences " to add to the thread since I posted an update on my experience with the ZS, over 5 hrs ago 

 

PEACE OUT

 

 

 

 

[JBChiangRai]

1 hour ago, jacob29 said:

https://www.scmp.com/business/china-business/article/3275699/chinese-ev-makers-losses-mount-rising-sales-fail-offset-steep-discounts

 

That doesn't help your point as none of those automakers are in the general Thailand yet.  By far the largest Chinese automaker sold here is BYD who are profitable.

 

My point stands that prices here in Thailand should not be substantially different from China.  Chinese automakers are not dumping their cars in China and if they are being sold elsewhere for more than that, then they are not dumping there either.

 

1 hour ago, motdaeng said:

 

i'm not a finance expert or a business expert...

but isn't it normal for every new car company to face years of losses before making profits?

the investment costs for a startup can easily reach a few billions of dollars...

 

tesla took about 15 years to produce at a profit, and now no one talks about that as a bad business

decision ... is there a different to the chinese ev car markers?

 

Yes, it's perfectly normal.  Costs are taken upfront and profits are taken as they are made.

[jacob29]

5 hours ago, JBChiangRai said:

That doesn't help your point as none of those automakers are in the general Thailand yet.

 

Which part of my comment related to Thailand? What I stated, and what you responded to asking for evidence, was

 

The vast majority of manufacturers are selling at a loss on the mainland

 

5 hours ago, JBChiangRai said:

My point stands that prices here in Thailand should not be substantially different from China.

 

That wasn't your point, your point was that prices in China were fair/reasonable. When close to the entire industry is selling at a loss, thats clearly not sustainable.

 

5 hours ago, JBChiangRai said:

Chinese automakers are not dumping their cars in China and if they are being sold elsewhere for more than that, then they are not dumping there either.

 

They could give them away for free and you wouldn't call it dumping, so let's ignore that term entirely since it's a red herring.

 

5 hours ago, JBChiangRai said:

Yes, it's perfectly normal.  Costs are taken upfront and profits are taken as they are made.

Even if it was 'perfectly normal', that doesn't imply that it's a fair market price. It can (and often does) mean below market (not normal) rate in order to capture market share. The company may well not be able to sustain those losses in multiple markets, especially as tariff risks increase if they're too aggressive slashing prices. Even China friendly nations like Brazil are introducing EV tariffs.

[jacob29]

7 hours ago, motdaeng said:

 

i'm not a finance expert or a business expert...

but isn't it normal for every new car company to face years of losses before making profits?

the investment costs for a startup can easily reach a few billions of dollars...

 

Some losses sure (until scale achieved), but these are pretty mature companies in some cases, and I'm not sure how else we can evaluate a fair market price for vehicles. BYD at a scale that matches the giants - is turning a profit of around $1000-$2000 per vehicle which is peanuts. So even the well established company with sales out the wazoo is on razor thin margins. Combine that with BEV steeply undercutting ICE cars on price, and the picture that emerges is not one of sustainable market prices.

[JBChiangRai]

18 hours ago, JBChiangRai said:

Chinese EV's are sold in China at a realistic price, nobody thinks they are dumping product there, yet their cars are much cheaper there than Thailand which IMHO should be harmonised to that price structure.  There is no valid reason they should cost so much more here.

 

 

8 hours ago, jacob29 said:

 

Which part of my comment related to Thailand? What I stated, and what you responded to asking for evidence, was

 

The vast majority of manufacturers are selling at a loss on the mainland

 

 

That wasn't your point, your point was that prices in China were fair/reasonable. When close to the entire industry is selling at a loss, thats clearly not sustainable.

 

 

They could give them away for free and you wouldn't call it dumping, so let's ignore that term entirely since it's a red herring.

 

Even if it was 'perfectly normal', that doesn't imply that it's a fair market price. It can (and often does) mean below market (not normal) rate in order to capture market share. The company may well not be able to sustain those losses in multiple markets, especially as tariff risks increase if they're too aggressive slashing prices. Even China friendly nations like Brazil are introducing EV tariffs.

 

Let's not lose context or twist my post, your post was in response to mine (above).

 

Whether some manufacturers haven't reached their anticipated profitability yet doesn't mean they are dumping or that it's unsustainable.  All new models are sold at a loss until development costs are recouped.  They need either substantial cash reserves or financial support until they hit that point.

 

Unsustainability only occurs if they run out of finance before that point. That can be down to many factors.  If a Chinese manufacturer can make and sell cars at a profit (eg BYD) than that means it's a sensible price for that segment.  It's up to the competition to compete.  It's not right to say the price is wrong and unsustainable as one manufacturer has already demonstrated it's ok.  If the competition is selling for less than that, it could well be unsustainable.

[jacob29]

6 hours ago, JBChiangRai said:

Let's not lose context or twist my post, your post was in response to mine (above).

I clarified the context explicitly, stating I was talking about the mainland. Don't blame your reading comprehension issues on me.

 

6 hours ago, JBChiangRai said:

Whether some manufacturers haven't reached their anticipated profitability yet doesn't mean they are dumping or that it's unsustainable. 

 

It's not some manufacturers not reaching profitability, it's nearly all of them, and even the profitable ones are on razor slim margins.

6 hours ago, JBChiangRai said:

All new models are sold at a loss until development costs are recouped.  They need either substantial cash reserves or financial support until they hit that point.

So don't ask me for evidence they're running at a loss - since you knew they all would be already. What are you even arguing at this point? You come to a different conclusion from the same data, but why this song and dance to arrive at that conclusion?

[JBChiangRai]

11 minutes ago, jacob29 said:

I clarified the context explicitly, stating I was talking about the mainland. Don't blame your reading comprehension issues on me.

 

 

It's not some manufacturers not reaching profitability, it's nearly all of them, and even the profitable ones are on razor slim margins.

So don't ask me for evidence they're running at a loss - since you knew they all would be already. What are you even arguing at this point? You come to a different conclusion from the same data, but why this song and dance to arrive at that conclusion?

Were not going to agree, I appreciate your point of view even though I disagree with it.

[KhunLA]

Renewed ins. w/Roojai

TTL loss value ฿560k @ ฿13,434

 

Not much difference that what many ins. carriers charge for ICE version of MG ZS

 

Y'all want to spit ball the depreciations %

... mythical ฿599k - almost none

... Purchase price ฿949k = ~41% (~14% (3 yo) or ~20 (2 yo)

... New sales price ฿829K = ~32%

... or 11% per year, this time next year (3 yo), or 16% now per year.

 

Irrelevant for us, as stated, will never sell, and worth much more repurposed to the solar system, in hopefully 10-15-20 yrs, if ever.   When ICE version of most cars will be worth -0-, the BEV battery pack will still be worth one to a few ฿100k 

 

Don't forget the ฿40-฿50k save with every 20k kms driven, depending if buying electrons from PEA, or FREE from solar.

 

Times 10 - 20 years ... yea, why would anyone buy a BEV  

 

[KhunLA]

On 9/14/2024 at 5:47 PM, KhunLA said:

 

On 9/14/2024 at 5:47 PM, KhunLA said:

Did another battery equalization, from 18% to 100%

Slow charging @ 7.4kWh

 

But, for some reason, stop charging @ 40% for about an hour, 

as I didn't notice.  Going to guess that affected slightly in a

negative way, if at all.   

 

Results were, according to the car,  ranges when

new @ 100% & now,  Along with what the pea meter

finished & started at, kWh used...

 

At the 14 month period & equalization, was only 0.6%, so considerably more, or one or both, were a bit flawed.  But, ballpark enough for me.

 

So end of battery warranty, 8 yrs, maybe about 10% degradation +/-

 

May Equalize it again in another 7 months, as CATL does recommend a couple times a year.  We've only done it twice.

 

NOTE:  ... WLTP range rating is 320, car in ECO mode is 360

Did another 'equalization', today, 6 weeks after the 'quoted' one above.  

 

As should be done (BYD info) when <10%, instead of 18%, and last time, it was interrupted.  So took the MG ZS down to 6%, and nothing changed.

 

Took 43.5kW to get back to 100%, and strangely, the same 6kW discrepancy, from what the car got, and what the grid provided.

 

So no need for the MG ZS to be taken down below 10%, (not a fan of) as same results as below 20%.

Edited October 27 by KhunLA

[UWEB]

9 hours ago, KhunLA said:

 

Did another 'equalization', today, 6 weeks after the 'quoted' one above.  

 

As should be done (BYD info) when <10%, instead of 18%, and last time, it was interrupted.  So took the MG ZS down to 6%, and nothing changed.

 

Took 43.5kW to get back to 100%, and strangely, the same 6kW discrepancy, from what the car got, and what the grid provided.

 

So no need for the MG ZS to be taken down below 10%, (not a fan of) as same results as below 20%.

Looks to me the usual 15% charging losses.

[KhunLA]

 

[JBChiangRai]

29 minutes ago, KhunLA said:

 

 

I'm not sure what this guy's qualifications are, but he's completely wrong.

 

He's wrong about deterioration vs. capacity, and he's wrong about active vs. passive balancing.

 

Tests have shown that LFP batteries cycled between low% and 25% ultimately give more power over their longer lifetime than batteries cycled (say) 75% to 100% or 50% to 100% etc.  The EE video posted elsewhere covers this in detail.

 

Most automakers use active balancers in their battery packs and I'm fairly certain BYD do for example, and I'm sure all NMC battery types do.  It's more expensive but more efficient and better.  MG use cheaper passive balancing (in LFP batteries)  which burns off the energy as heat in higher voltage cells until it matches the lowest voltage cell.  This typically only happens above 90%.  Active balancing occurs during all charging & discharging.

 

I have done a google search and cannot find a single article agreeing with what this guy says, all of them disagree with him.

 

 

 

AI says

The main difference between active and passive balancers is how they manage energy in a battery pack: 

Active balancers

Redistribute energy between cells during charging and discharging, which can improve efficiency and increase run-time. Active balancers can adjust cell voltages faster than passive balancers. 

Passive balancers

Dissipate excess energy from higher voltage cells during the charge cycle. Passive balancers are low cost and have a simple circuit design. However, they can only be used during the charge cycle, and they waste 100% of the balanced power as heat. 

Here are some other differences between active and passive balancers: 

Energy efficiency: Active balancers are more efficient than passive balancers because they don't waste energy as heat. 

Cell life: Active balancers can improve the life expectancy of cells. 

Balancing time: Active balancers can adjust cell voltages faster than passive balancers. 

Balancing conditions: Active balancers can work 24 hours a day until the pressure difference between cells is less than a set value. 

 

Cell Saviours Active Balancing vs Passive Balancing Differences - Cell Saviors

says

Active balancing redistributes charge among the cells in a battery pack to ensure that they all have the same state of charge with a dedicated circuit, which monitors the voltage of each cell and adjusts the charging and discharging current accordingly. Active balancing is more accurate and faster than passive balancing. On the other hand, passive balancing relies on Ohm’s Law and the natural cell and balance resistor characteristics to bring cells to the same state of charge. Passive balancing is generally less accurate and slower than active balancing and may take longer to achieve the desired result. 

 

EEPower Active and Passive Battery Pack Balancing Methods - Technical Articles

says

Active Cell Balancing

The active cell balancing technique uses inductive charge shuttling or capacitive charge shuttling to transfer the charge between the cells. This technique is proven to be an efficient approach as it transfers energy to where the energy is needed instead of wasting it. However, this demands additional components to be added to the system which in turn translates to increased cost.

 

Passive Cell Balancing

The passive cell balancing technique uses the idea of discharging the cells through a bypass route that is mostly dissipative in nature. It is simple and easier to implement than active balancing techniques as the bypass can either be external or be integrated — keeping the system more cost-effective either way. However, since all the excess energy is dissipated as heat, battery run time is adversely impacted and is less likely to be used during discharge.

 

Maxkgo Active vs Passive Balancing: Which is Best for Your Lithium Battery? | MAXKGO News blog

says...

·Is active balancing better for electric vehicles?

The answer is yes. Active balancing is generally better suited for electric vehicles (EVs). It provides a more efficient and power-saving balancing method.

Active balancing is different from passive balancing. Passive balancing releases energy as heat, while active balancing moves energy between cells.

This process does not generate much heat. Therefore, it can save more power. This energy-saving method is great for large battery packs in electric vehicles (EVs). The main goal for EVs is to keep the batteries healthy and extend driving time.

 

 

 

 

 

 

Edited Friday at 03:06 AM by JBChiangRai
Spellong

[Pib]

On 11/8/2024 at 10:01 AM, JBChiangRai said:

Most automakers use active balancers in their battery packs and I'm fairly certain BYD do for example, and I'm sure all NMC battery types do.  It's more expensive but more efficient and better.  MG use cheaper passive balancing (in LFP batteries)  which burns off the energy as heat in higher voltage cells until it matches the lowest voltage cell.  This typically only happens above 90%.  Active balancing occurs during all charging & discharging.

 

 

I've been interested over the last month regarding how my BYD Atto 3 LFP 60.5KWH battery is designed for cell balancing.  It has 126 cells with each cell being a 152AH cell.   Below is a snapshot/partial quote from the website from a guy who bought a wrecked Atto 3 just to get the traction battery which was undamaged, disassembled the battery as much as possible, and converted it to a home solar battery storage pack.   

 

Below are some snapshots of one of the BMS daughter boards (10 total such daughter boards plus a motherboard in the front of battery) which indicates it uses passive resistor balancing where two 10 ohm resistors in series for each cell along with a BJT transistor/MOSFET  are used for balancing---classic components for a BMS that uses passive resistor balancing.   So on any motherboard that manages 14 cells you'll count 28 ten ohm resistors on heat dissipation pads and 14 nearby MOSFETs along with other components.   You will also notice no bank of inductors (like 14 inductors instead of 14 resistors), capacitors (like 14 capacitors instead of 14 resistors), or a transformer on the daughter boards which would indicate "active balancing."

 

And this passive balancing works really well according to OBD2 data on my Atto.   I've monitored the Cell Voltage Delta/Balance for weeks now....it's typically has a cell balance/delta of only 7 millivolts while idling, driving steadily, and charging although at around 99% charged while charging the cell balance will go to approx 250mv briefly, but after charging completes at 100% charge the balance quickly returns to approx 7mv after just a couple kilometers/around 10 minutes of driving....when reaching approx 99.5% charge level.  

 

I expect the BYD Dolphin and Seal (and similar BYD BEVs) use the same passive balancing approach.

 

https://forums.aeva.asn.au/viewtopic.php?t=8323

 

Snapshots of an BMS daughter board from an Atto battery.  

 

The cells have BMS boards covering the terminals down the right side (drivers side in RHD countries).
The boards span 12 and 14 sets of cells (3x 14s boards and 7x 12s boards) and appear to be powered from the cells themselves as there are only 2 data wires coming out of the contactor block at the front and linking each board in a daisy chain fashion. Each board also has a temperature probe going into the cells.

 

 

The lower edge of the board has the inputs from the busbars and they get passed through to the upper edge. This is along circuit tracks on the underside of the board.
Then there are vias that take the traces through to the top of the board to all the balancing guff.
The balancing guff consists of a transistor and 2x 10 Ohm resistors in series with each other.
The upper edge of the board has the inputs from the terminals on the cells that go to the other side of the pack. Strangely enough it also has nickel strips that link the near side busbars to the other side of the pack. But then they aren't connected to anything.

 

 

Edited Sunday at 01:29 PM by Pib

[Pib]

And just to supplement my above post I think the BYD passive balancing daughter boards are basically larger versions of the resistive balancing board talked below at around 13:52 into the video.

 

 

I will also add where I mentioned in my earlier post a brief cell balance of around 250mv just before hitting 100% while charging but it quickly goes back to around 7mv, that 250mv brief imbalance is mostly "surface charge" which contains very, very little capacity and is quickly consumed under normal battery load. 

 

 Same thing happens when you fully charge a good ol' 12V lead acid battery and then immdiately check the voltage which is probably going to be a little over 13 volts...maybe even around 13.5 vs the nominal voltage of around 12.6 to 12.8V.  Turn the headlights on for 15 seconds or so and the battery's surface charge will get consumed very quickly and then the measured voltage with headlights off will now be around 12.6 to 12.8V.

 

 

Edited Sunday at 01:42 PM by Pib

[JBChiangRai]

13 hours ago, Pib said:

 

I've been interested over the last month regarding how my BYD Atto 3 LFP 60.5KWH battery is designed for cell balancing.  It has 126 cells with each cell being a 152AH cell.   Below is a snapshot/partial quote from the website from a guy who bought a wrecked Atto 3 just to get the traction battery which was undamaged, disassembled the battery as much as possible, and converted it to a home solar battery storage pack.   

 

Below are some snapshots of one of the BMS daughter boards (10 total such daughter boards plus a motherboard in the front of battery) which indicates it uses passive resistor balancing where two 10 ohm resistors in series for each cell along with a BJT transistor/MOSFET  are used for balancing---classic components for a BMS that uses passive resistor balancing.   So on any motherboard that manages 14 cells you'll count 28 ten ohm resistors on heat dissipation pads and 14 nearby MOSFETs along with other components.   You will also notice no bank of inductors (like 14 inductors instead of 14 resistors), capacitors (like 14 capacitors instead of 14 resistors), or a transformer on the daughter boards which would indicate "active balancing."

 

And this passive balancing works really well according to OBD2 data on my Atto.   I've monitored the Cell Voltage Delta/Balance for weeks now....it's typically has a cell balance/delta of only 7 millivolts while idling, driving steadily, and charging although at around 99% charged while charging the cell balance will go to approx 250mv briefly, but after charging completes at 100% charge the balance quickly returns to approx 7mv after just a couple kilometers/around 10 minutes of driving....when reaching approx 99.5% charge level.  

 

I expect the BYD Dolphin and Seal (and similar BYD BEVs) use the same passive balancing approach.

 

https://forums.aeva.asn.au/viewtopic.php?t=8323

 

Snapshots of an BMS daughter board from an Atto battery.  

 

The cells have BMS boards covering the terminals down the right side (drivers side in RHD countries).
The boards span 12 and 14 sets of cells (3x 14s boards and 7x 12s boards) and appear to be powered from the cells themselves as there are only 2 data wires coming out of the contactor block at the front and linking each board in a daisy chain fashion. Each board also has a temperature probe going into the cells.

 

 

The lower edge of the board has the inputs from the busbars and they get passed through to the upper edge. This is along circuit tracks on the underside of the board.
Then there are vias that take the traces through to the top of the board to all the balancing guff.
The balancing guff consists of a transistor and 2x 10 Ohm resistors in series with each other.
The upper edge of the board has the inputs from the terminals on the cells that go to the other side of the pack. Strangely enough it also has nickel strips that link the near side busbars to the other side of the pack. But then they aren't connected to anything.

 

 

 

Very interesting, and I'm surprised.

 

The MG's behave very differently at the end of the charge cycle, they display 100% charged but continue to draw power in small amounts from the charger for anything up to 20 minutes before the car charging port display switches off to indicate finished and my wall charger disconnects.

 

I would like to understand the process of a BYD balancing the cells as it's clearly not done after charging at 100%.

[Pib]

While many websites talk how active balancing is better in some ways than passive balancing and some of these website sites state/imply is good for EV battery packs I haven't found one yet that specifically states that EV model so-in-so uses active balancing (excluding a few websites which shows disassembly of a battery pack/reverse engineering a BMS to really see what type of balancing is apparently being used).

 

Like say the BYD EV battery packs in the Atto, Seal, Dolphin, etc., use active balancing per BYD provided documentation/specs.  Or Tesla battery packs like in the Model S Plaid use active balancing, etc., per Tesla documentation/specs.   

 

It seems most of these websites are just expressing an opinion or generalizations that for those actively involved in DIY home solar battery storage systems; DIY electric vehicles (EV) which could really mean a home-made EV bike, EV golf cart, etc.;  EV cars probably use active balancing since active balancing vs passive balancing is probably better, etc.;, that if you want the best balancing then go with active balancing which uses a more complicated BMS systems, chips, inductors, capacitors, transformers  vs the less complicated BMS passive balancing system that is less complicated, lower cost, uses simple bleed resistors, etc. 

 

And this is not to imply passive balancing is not OK-fine and active balancing "may" be a little better and faster.....a faster and better that  person may not actually be able to really see or benefit from in their day-to-day use of these "battery powered" system.

 

Since I mentioned Tesla EVs....what kind of balancing do they use....active or passive?   I doubt you'll find any Tesla-provided documentation/specs that specifically states what is used since it's apparently proprietary information.  But a person can usually find some website where someone has reverse engineered, disassembled an EV manufacturer's battery pack and BMS system to determine whether active or passive balancing is being use.   Like in above/earlier BYD battery disassembly which shows "passive resistive balancing" is used. 

 

And like below Tesla Model S Plaid battery pack/BMS reverse engineering video where it shows the Battery Management daughter boards on the Tesla battery pack use "passive balancing bleed resistors."  See below snapshot from the video also posted below....where it talks the balancing used is around the 4:20 point.

 

I'm of the opinion that although active balancing may be better than passive balancing "on paper" and in some applications that does not mean EV vehicles like the BYD, Tesla, MG, etc...etc...etc., cars and trucks driving on the roads today use the more expensive and complicated active balancing in their battery packs.  But instead use a simpler and lower cost passive balancing system that still meet cell balancing needs.  A passive balancing system that may not be as good/fast as an active balancing system, but still more than good enough, OK-fine, works just fine, etc. to keep the EV battery pack cells balanced and in good condition that exceeds the expected life of the vehicle. 

 

 

 

 

[JBChiangRai]

It looks to me like it's a bit more than the passive balancing as featured on the MG at the end of charge cycle.

 

I suspect the microprocessor is looking at the voltage of all the cells and bleeding off charge from any cells that are overvoltage.  It probably happens all the way up and down charge/discharge cycles and not just at the end of the charge cycle as on the MG.

 

I would like to know the process if you ever find out how it's done.

 

If it is all the way up and down the charge/discharge cycle, then the same process would be suitable for NMC batteries too.

[Pib]

Below are some snapshots of my BYD Atto battery pack OBD2 data monitoring over recent months relating to cells balance.....see the words I added above each snapshot for more info.   My words concentrate on cells imbalance between the 126 blade cells in the Atto's 60.5KWH battery pack

 

************************

 

Just finished charging the Atto to 100% using a DC Fast Charger

on 26 Oct 2024.  At the instance charging completes/now at 100% the 126 LFP blade

cells imbalance (a.k.a. delta) is 166mv. Normal balance would be under 10mv based on

my OBD2 data monitoring over numerous months.. But I already know the high imbalance

is predominately "surface charge" that has very, very little capacity and will dissipate

very quickly under normal battery load.....just like it happens on a ol' 12V lead acid battery 

right after you finish fully charging it.

 

 

 

 

Now after charging to 100% I wanted to see how long it took for the cell imbalance to

get back around it's 7mv as I drove away.  After driving around 4Km/5 minutes on 26 Oct the cells balance among
all 126 cells in the Atto battery pack is now back within 7mv as that surface charge was

quickly dissipated.   Since I have been charging to 100% approx once per week which recalibrates the

charge percentage/range display/BMS the cells have stayed in excellent balance which is a good thing.

 

But how much imbalance is too much?  10mv, 100mv, 200mv, etc?  Well, from tons of googling and watching

way too many Youtube videos (both bad and good videos) I'm still not sure at what millivolt imbalance is considered too high "when the battery is under normal load or been setting static/unloaded for a while."  A lot of websites/Youtube videos related to DIY home solar/DIY electric vehicles indicate that most cell balancers don't activate until an imbalance of 100 or 200mv is reached...then they activate to attempt to bring cell balance back to within a certain range over a few hours to maybe over several days.   At one time I did stumble upon a conversation on BYD EV battery pack cells balance where several people was saying their battery imbalance was 20mv, another one said 10mv, another one 6mv, etc....and they were wondering how much is too much.  Several people mentioned it should be within 100 or 200mv based on what they know (or think they understood) about home solar battery storage systems but really didn't know what an EV battery should be.  Then one guy entered the conversation for just a few posts who said he worked as an engineer at BYD for several years and said 60mv is the spec BYD uses for a LFP blade battery that has balanced/operating under normal/steady loading conditions.  Was this supposedly former engineer (of some type) who worked at BYD correct or not....I don't know as he didn't post any reference to authoritative BYD published docs/specs which would probably be proprietary data.

 

 

 

 

And finally, he's a 11 Nov 2024 snapshot from just a few minutes ago

as my Atto sets in my carport getting reading to be turned on an make a

morning groceries run to Lotus.  Cells imbalance is a mere 6mv.  Once I turn the Atto on

the cells imbalance will be around 7mv...and while I drive along with a steady

foot on the fuel pedal it will vary a little but stay under 10mv.  But if I press the pedal

to briefly over-take another vehicle the cell imbalance will "very" briefly jump up to around

50mv and then with a few seconds come back to under 10mv...right around 7mv as I steadily

drive along

 

 

 

Da end.

 

 

 

 

 

 

 

 

 

 

 

[Pib]

5 hours ago, JBChiangRai said:

 

The MG's behave very differently at the end of the charge cycle, they display 100% charged but continue to draw power in small amounts from the charger for anything up to 20 minutes before the car charging port display switches off to indicate finished and my wall charger disconnects.

I"m going to guess that although the MG BMS indicates 100% once a certain cell voltage is reached for a few seconds---a voltage such as at least 3.65V which is generally considered the 100% charged voltage level for a LFP cell---the BMS knows that even when 3.65V is initially reached if continuing to charge at a constant voltage of 3.65V but at a low current (i.e., just an amp or two) for X-period of time the battery can still absorb a little more capacity (maybe a percent or two) without damage to the cell and also help in the cells balancing process. 

 

The BMS might be programmed to continue charging X-amount additional minutes (like maybe 20 minutes, 30 minutes, etc) after reaching 3.65V average cell voltage.     OR, it might be programmed to continue charging at a "low" current level...lets just say 1 or 2A for discussion purposes....and it will then continue tapering "down" that amperage level to around a few tenths of an amp and let's say completely stop charging when the current reaches 0.2A as the battery capacity is now full-full.

 

This on-top absorption  period (i.e., when initially reaching 3.65V which represent 100% charged) is not to be confused with the main/primary/long absorption period on the way to reaching a certain voltage level like 3.65V.

 

And a LFP cell can still be charged to 100% KWH/AH capacity even if not allowing it to reach 3.65V but instead just charging at 3.45V "for a longer time" which is increasing the absorption period.     But if not wanting to take extra time to maximize charge capacity then allowing it to charge up to 3.65V gets the charging done faster.   I expect EV manufacturers know their EV customers want the charging done as quick as possible and the way to do that is to allow cell charging up to 3.65V versus only allowing 3.45V or 3.55V with an extended, low amperage charge period. 

 

MG may have found a good compromise in showing 100% charged which is when most drivers would probably unhook the charger to continue their trip OR if the customer can wait a little longer to let the battery continue to charge at a low amperage level (i.e., that top-in extra absorption period) then the battery can take in a little more capacity (maybe get a little more Km range from a cell balancing/adding just a little more KWH capacity) although the charge percentage will not increase above 100%....and maybe even the Km range will not increase but as you drive along it's actually decreasing at a slightly slower rate since the battery took a little more capacity from that extra absorption period.     

 

There are different ways at different voltage and current levels to fully charge a 3.2V LFP or 3.6 NMC cell. I expect battery/EV manufacturers have different opinions on how they will build and charge their  BMS and battery pack.

 

Edit: oh, just remembered, regarding my BYD Atto final bit of charging.  From monitoring OBD2 data while DC and/or AC charging and the percent charged indicator on the car is displaying 99% you can tell that very soon it's going to change from 99% to 100" when the  "calculating...." message starts displaying which I assume means the the system is recalculating/recalibrating the BMS and charge percentage indication system.   

 

Although going from 99 to 100% takes around 5 minutes on a 7KW wall charger at around the 1 to 2 minutes to go point the "calculating...." message appears and this always seems to appear when the cell with the lowest voltage finally reaches 3.55V, repeat, 3.55V, for at least a few seconds while the cell with the max voltage is usually indicating around 3.65-3.75 volts.   That "calculating..." message does not appear until the cell with the lowest voltage reaches 3.55V for a few seconds....then just a minute or so later the charging stops.   And if using a DC charger that same 3.55V min cell voltage still applies regarding appearance of the "calculating...." message, but since you are still pumping in a higher current than a wall charger would be the charging completes within 15 to 30 seconds.  100% finally appears and zero charging current is occurring. 

 

So, it seems BYD's approach is to get "each & every" cell of the battery pack (126 cells in my 60.5/KWH battery pack) up to at least 3.55V and then it considers the pack fully charged....time to start "recalculating /recalibrating" the BMS system.   And from googling/watching YT videos it seems 3.55V is a very popular max cell charging voltage in the DIY home solar community as it's considered to have brought a cell to full 100% and will have been enough voltage to properly balance it when that cell is just one of many cells comprising a battery pack where there is always going to be a little bit of cell imbalance.

 

 

Edited Monday at 08:41 AM by Pib

[KhunLA]

Exploring locally & charging with solar afterwards.

 

Popped up to Hua Hin Monday, ~200 kms R/T, using ~60% battery, leaving @ 100%, returning @ 40%.

 

Sunny skies forecast and solar battery packs @ 60+%, so plugged in before producing enough for house, let alone charging the BEV.  By 0800 hrs, enough for both, till about 1600 hrs.  ~18kWh going to the BEV, with rest going to house load.   Both ACs on (13k &24k BTU), as a bit warm, from about 0900-1700 hrs.

 

 

We usually charge the car when gets in the 80% state of charge during rainy season, as 'charge when you can' rules, since sometimes, barely enough just for the house produced, when overcast & rainy.

 

Went from 40% to 80% yesterday, and will top up today, as been charging since 0700 hrs.  Will be using the E-MC for dog's park run, as I did yesterday, going to Makro & park.

 

Of course if needing the car the next day, can simply charge using wall charging cable (7.4kWh) & grid, instead of solar & granny/emergency charging cable (2.3kWh).

 

When not overcast or cloudy, can produce 50kWh a day.  Charging every other day isn't eve noticed.  

~240 kWh for the month, ~18% of that was yesterday.