What stage of battery decline would register a fault?

[Sailordoc]

Hi all,

Just got EvBatMon and found that my 2015 PHEV is showing 87.6% of original capacity after only 21 months and 32000 miles, where it has been charged virtually every day.

This got me thinking that the chances of the car being at 80% of original capacity at 10 years (As Mitsubishi claim it is supposed to be) is close to the square root of sod all! However, I don't want to sell the car whilst it has a decent amount of battery life left, but obviously wouldn't be able to sell it once the battery registers as a fault.

Does anyone know whether there is a certain percentage of original capacity that would show up as a battery fault, or is it just down to when cell failures start being detected? It would help to know whether it's time to sell once it hits 81% for example.

 

[elm70]

I assume that 87.6% is the "Battery Condition" in EvBatMon

I still have to get the meaning of this "Battery Condition"

My PHEV which is a Dec 2013 and 124k km ... report 94.47% in "Battery Condition" .. but only 36A as "battery capacity" (actually this recently drop to 35.9A, while the "Battery Condition" still is reported as 94.47%

So ... in reality my car was 90% condition, and now did drop to 89.75%

This just for say .. that already EvBatMon is a tricky tool to be used for check the car battery status

Back to the warranties ... there is no warranty that grand the car to have 80% condition after 8y .. this is just an expectation .. but does not implies any compensation or fix in case the condition will be 70% after 7y

Anko is the expert in this subject .. so probably he will be correcting me here ... anyhow this is my understanding

The warranty will kick in only if there is a "mayor" issue

For instance .. if you found out that one of the 80 battery cell does have a voltage much lower or much higher then the rest ... you may have a case for claim the warranty over the battery ... inside the 8y of car life

In my case ... I can't spot any cell that is weaker then the rest .. so all cells are kept on the same voltage with just 0.02v margin between max and min .. as well .. reported temperature of each cell/module don't show any strange result.

PS: I think my car is ageing relative well from the battery point of view, since my previous owner did broke the charger and was not charging anymore the car .. and leave fully charge the car does cause the battery to age faster .. so ... when I have to leave my car unused even for only 1 day, I do avoid to top up the battery ... on the other side ... when the battery is zero on the dash, in reality the state of charge is 30% that is the ideal status for "store" the battery when not used

 

[Sailordoc]

I assume that 87.6% is the "Battery Condition" in EvBatMon

I still have to get the meaning of this "Battery Condition"

My PHEV which is a Dec 2013 and 124k km ... report 94.47% in "Battery Condition" .. but only 36A as "battery capacity" (actually this recently drop to 35.9A, while the "Battery Condition" still is reported as 94.47%

So ... in reality my car was 90% condition, and now did drop to 89.75%

This just for say .. that already EvBatMon is a tricky tool to be used for check the car battery status

Back to the warranties ... there is no warranty that grand the car to have 80% condition after 8y .. this is just an expectation .. but does not implies any compensation or fix in case the condition will be 70% after 7y

Anko is the expert in this subject .. so probably he will be correcting me here ... anyhow this is my understanding

The warranty will kick in only if there is a "mayor" issue

For instance .. if you found out that one of the 80 battery cell does have a voltage much lower or much higher then the rest ... you may have a case for claim the warranty over the battery ... inside the 8y of car life

In my case ... I can't spot any cell that is weaker then the rest .. so all cells are kept on the same voltage with just 0.02v margin between max and min .. as well .. reported temperature of each cell/module don't show any strange result.

PS: I think my car is ageing relative well from the battery point of view, since my previous owner did broke the charger and was not charging anymore the car .. and leave fully charge the car does cause the battery to age faster .. so ... when I have to leave my car unused even for only 1 day, I do avoid to top up the battery ... on the other side ... when the battery is zero on the dash, in reality the state of charge is 30% that is the ideal status for "store" the battery when not used

Yes, that figure is the battery condition in EvBatMon. The capacity is stated as 33.3 Ah. There are a few cells showing up as cell failures after a full charge, but I've only been using the app for a couple of days and a few of these cells change between cell failures and being OK which makes me doubt the accuracy of the measurements. There is also a large range in voltage values which seems a bit odd so I also wonder if the OBD adapter could be an issue although no errors are reported.

Let's see if I can add the image here:

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[elm70]

33.3h .. in theory is only 83.25% (battery capacity as new is supposed to be 40Ah) ... so is still a mystery for me how EvBatMon make this "Battery Condition"

About your graph ... you must know .. I can't get this graph on my EvBatMon .. I'm possibly missing how to get it.

Personally ... I'm checking either the first page "Battery" or my custom page. The main first page is the one that show the car on the top, and SOC Real in the middle .. there is visible the Max and Min Volt Cell .. or my custom page (which is perfect for have the logging of lot of data, only shown data are logged by EvBatMon)

There you should see number between 3.5 to 4.1v ... 3.5 only when the car is moving . else it should be never under 3.7 even if 0% battery is shown on the dash.

Definitely your graph that show value with 36v up to 41v .. make no sense, so nothing can be concluded looking at it .. except that it make no sense and can't be used as reference ... a single cell is max 4.1v (or 4.2v for mobile phone cells)

My EvBatMon does provide quite some consistent data .. I have log active so I inspected data collected while driving for 20+ min .. without notice any strange sporadic number

I'm using the OBDlink LX which is possibly one of the best ODB2 Bluetooth adapter on the market, which I paid "only" 55 euro so not too bad .. my previous cheap ebay OBD2 did not work at all with EvBatMon (less then 10 USD from china .. but if don't work, is just 10USD wasted)

PS: I'm using Android .. not sure if EvBatMon has a iOS version too which may have different functions

 

[elm70]

Anyhow .. a check of battery health condition ...

My car with 35.9Ah .. does around 40km Ev range (almost at my best, driving slow, which is "hard" for my driving style) ... so with 33.3h ... you should manage around 37km ... if you have much less .. then you may want to check in detail the battery status

What is critical in theory is how low volt can have the lowest cell, when the car show zero or very low range left ... it is important that no cell go below 3.3v (in theory lowest is 2.5v .. still ... in my book anything below 3.5v (unless car is pushing 60kw power) should be avoided for keep long the life of the single battery cell

 

[Sailordoc]

33.3h .. in theory is only 83.25% (battery capacity as new is supposed to be 40Ah) ... so is still a mystery for me how EvBatMon make this "Battery Condition"

About your graph ... you must know .. I can't get this graph on my EvBatMon .. I'm possibly missing how to get it.

Personally ... I'm checking either the first page "Battery" or my custom page. The main first page is the one that show the car on the top, and SOC Real in the middle .. there is visible the Max and Min Volt Cell .. or my custom page (which is perfect for have the logging of lot of data, only shown data are logged by EvBatMon)

There you should see number between 3.5 to 4.1v ... 3.5 only when the car is moving . else it should be never under 3.7 even if 0% battery is shown on the dash.

Definitely your graph that show value with 36v up to 41v .. make no sense, so nothing can be concluded looking at it .. except that it make no sense and can't be used as reference ... a single cell is max 4.1v (or 4.2v for mobile phone cells)

My EvBatMon does provide quite some consistent data .. I have log active so I inspected data collected while driving for 20+ min .. without notice any strange sporadic number

I'm using the OBDlink LX which is possibly one of the best ODB2 Bluetooth adapter on the market, which I paid "only" 55 euro so not too bad .. my previous cheap ebay OBD2 did not work at all with EvBatMon (less then 10 USD from china .. but if don't work, is just 10USD wasted)

PS: I'm using Android .. not sure if EvBatMon has a iOS version too which may have different functions

Yes, that is why I doubt the accuracy! The front screen shows max cell volt as 3.97V, min 3.96V which is more what I expect.

 

[anko]

I think you need to check you OBDII adapter, rather than your battery ;-)

 

[Sailordoc]

I think you need to check you OBDII adapter, rather than your battery ;-)

It is the AlbaBKC SuperOBD recommended as compatible by evpositive.com and EvBatMon is connecting to it and getting readings which are consistent in terms of battery status - see screenshot. If there are errors, such as the cell values above, surely the app should pick this up and report it? If not, then the app is useless as it cannot be relied upon and I can't really keep buying endless OBDII adaptors until one gives readings I like - how would I know it is correct?

 

[Sailordoc]

Anyhow .. a check of battery health condition ...

My car with 35.9Ah .. does around 40km Ev range (almost at my best, driving slow, which is "hard" for my driving style) ... so with 33.3h ... you should manage around 37km ... if you have much less .. then you may want to check in detail the battery status

What is critical in theory is how low volt can have the lowest cell, when the car show zero or very low range left ... it is important that no cell go below 3.3v (in theory lowest is 2.5v .. still ... in my book anything below 3.5v (unless car is pushing 60kw power) should be avoided for keep long the life of the single battery cell

Range varies with temp as well as speed. At present, with temps of around 10C, I am getting around 26-28 miles (42 - 45 km) from the battery in stop start city slow speed driving. Earlier in Winter I was getting around 20 miles (32km) if I used pre-heat and only used the heated seats. I'm not worried about the battery now, I'm trying to work out whether it really is at 33.3Ah, and at what capacity faults will show during checks. It certainly doesn't look as though the EvBatMon cell graphs are true, but the front screen may be :?

I'll do a check when the battery is 'empty' as you suggest and post the result for information.

 

[anko]

zzcoopej should be able to confirm, but I am pretty sure the info on the front screen is populated from a different OBD request (which provides highest and lowest cell numbers plus there actual values (among other things)) than the per-cell information. The latter is derived from a huge multi-frame OBD response, that shows two values for each cell. Looking at how every eight cell (starting with #9) has the same odd reading, I would think the data is not handled properly.

As we know that EvBatMon is capable of handling the data well, the logical suspect would be the adapter (IMHO).

 

[Sailordoc]

zzcoopej should be able to confirm, but I am pretty sure the info on the front screen is populated from a different OBD request (which provides highest and lowest cell numbers plus there actual values (among other things)) than the per-cell information. The latter is derived from a huge multi-frame OBD response, that shows two values for each cell. Looking at how every eight cell (starting with #9) has the same odd reading, I would think the data is not handled properly.

As we know that EvBatMon is capable of handling the data well, the logical suspect would be the adapter (IMHO).

I've already emailed the firm to ask if it could be an OBD issue, and will let you all know what they say. What I really want to know is whether the battery capacity and front screen info is accurate :?

 

[Sailordoc]

Had a reply from Jeremy. The front screen data looks accurate to them, and the problem with the individual cell readings is something that they have seen quite a bit before although the cause is uncertain. However, they seem happy that it does not affect the front screen data so it does look as though my battery is down to 33.3 Ah. I'll check again in a month or so to get more data points, and will also check when the battery is 'empty' as previously suggested to look at minimum cell value