Drive battery degradation . Houston, do we have a problem?

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elm70 said:
Was always the charging process completed when highest voltage per cell was 4.10v ?

In case ... it is maybe due to some unbalance

Else ... the BMU intentionally avoid to charge up to 4.10v the battery ... which is very "strange" ... or maybe it is one of their way to protect the car which may be left connected to a charger for "days"
I am pretty sure it was. Reason for < 100% could also be because my SoH number is still over inflated, regardless of last drop off.


elm70 said:
The main difference is that nobody would leave a hobby battery connected to the charger for days or even hours after the charging process is finish ... while this could happen on a PHEV
That cannot happen, I think. The charger is in the car remember? When the charger thinks the battery if dull, it shuts itself down. As a matter of fact the battery is completely isolated from the rest of the car. You can hear the main contactor clicking about when charging starts / finishes.
 
elm70 said:
PS: For sure the charging process of our PHEV is a bit difference, since the initial phase more then charge at constant current, it is a charge at constant power ...but .. it would be interesting to see and monitor the final phase of the charging process ... mainly how evolve the charging current based on the cell voltage
Like this?

image.png


hmmm, looks much better on my screen. Can you see this:

p.png
 
Unexpected (to me), very short after the charging process starts to taper off, pack and cell voltages are already at their maximums. But SoC is still 5% below max value.
 
elm70 said:
The main difference is that nobody would leave a hobby battery connected to the charger for days or even hours after the charging process is finish
Really? You clearly don't have a number of cameras that you use intensively - and a large number of batteries for them - and quite a few chargers-. ;) :ugeek:
 
jaapv said:
elm70 said:
The main difference is that nobody would leave a hobby battery connected to the charger for days or even hours after the charging process is finish
Really? You clearly don't have a number of cameras that you use intensively - and a large number of batteries for them - and quite a few chargers-. ;) :ugeek:
But, looking at your signature, yours are not hobby batteries, are they? :p
 
jaapv said:
elm70 said:
The main difference is that nobody would leave a hobby battery connected to the charger for days or even hours after the charging process is finish
Really? You clearly don't have a number of cameras that you use intensively - and a large number of batteries for them - and quite a few chargers-. ;) :ugeek:

I guess you are not using a charger like this:

183655u_3.jpg


https://hobbyking.com/en_us/turnigy-reaktor-1000w-30a-balance-charger.html

Nor battery like:
115407.jpg


https://hobbyking.com/en_us/multistar-high-capacity-6s-12000mah-multi-rotor-lipo-pack-1.html


PS: I guess link of pictures don't work, since I bet there is a session ID inside the URL :?
 
anko said:
Unexpected (to me), very short after the charging process starts to taper off, pack and cell voltages are already at their maximums. But SoC is still 5% below max value.

I can't really see the picture attached above ...

So SOC is 95% when cell voltage reach 4.1v and charging current is declining ?
This looks relative normal
 
But, looking at your signature, yours are not hobby batteries, are they?
A bit out of control, but still a hobby, more or less. However, the distinction between advanced amateur and professional gear is negligible, if at all.
 
Thanks Anko

What is the difference between the red line (which was ending the charge at 4.110v) and the orange line (which was at 4.101v) ?
Was two different charging processes, or are these the max and min cell in the battery pack ?

Yes, apparently , it is looking a perfectly normal charging process :geek: .. actually ... the precise flat line is very suspicious

About the suspicious ... I would expect the balancing process ongoing while the battery is in the final phase of the charging process, so the max voltage cell should have a load for reduce its capacity ... and this normally is not compatible with a perfectly constant voltage
 
anko said:
Red line is total pack voltage (plotted against right Y-axis). Orange line is max cell voltage (plotted against left Y-axis).

So ... 328v pack voltage constant and 4.101v (moving to 4.100 and 4.099) for max cell.

It is looking a quite well balanced pack on the max voltage (which does not means it is also balance at different charge level and/or different loads)

Did you ever notice if in the past the charging voltage was higher ? I think my old firmware was charging more then my current one ...
 
This is supposedly the procedure for PHEV MY 14-16 a dealer should follow before a claim for battery replacement can be filed with MMC after a customer complains about reduced range and the battery is still under warranty:
1) Check Battery current capacity: above 26Ah is OK (no further action)
2) Less than 26Ah? Charge via CCIB box at 10Amp
3) Charged? Then check cell voltage difference (BMU data list #22)
4) Cell voltage difference < 0,020V? Check capacity: >26Ah OK (no further action), <26Ah go to 6)
5) Cell voltage difference > 0,020V? Perform cell smoothening with MUT-IIISE & check Cell Voltage < 0,020V
If > 0,020V repeat the procedure for smoothening cells for a maximum of 3 times.
Check Battery current capacity: above 26Ah is OK(no further action), < 26Ah go to 6)
6) When Cell voltage difference <0.020V and capacity below 26Ah OR action 5) was unsuccessful after 3 attempts & < 26Ah the dealer can request for battery replacement.

Bottom line: when smoothening doesn’t bring up the capacity above 26Ah a claim can be made.
 
MikeB said:
This is supposedly the procedure for PHEV MY 14-16 a dealer should follow ....
Thanks for sharing, Mike. Any source for this? On FB, a different procedure was shared from different sources that involves the DBCAM procedure. DBCAM goes a bit further than just cell smoothing. I have been denied a warranty claim twice, because capacity ended up above the threshold after a DBCAM procedure.
 
A dealer showed me this procedure after my complaint the range was notably less. So I started at <26Ah and after this procedure it's over 26Ah again.
This like to see me again in a couple of months.
 
MikeB said:
A dealer showed me this procedure after my complaint the range was notably less. So I started at <26Ah and after this procedure it's over 26Ah again.
This like to see me again in a couple of months.
An official Mitsu document from Finland, that was posten in the PHEVWatchDog FB page describes almost exact same procedure, but towards the end it requires a DBCAM procedure, not a cell smoothening procedure. And indeed, a DBCAM is likely to increase your SoH, a cell smoothening procedure not so much.
 
How about these SoC jumps during the cell balancing phase of AC charges?

We know SoC can be adjust up or down during cel balancing. I just saw a jump from 80,0% to 85+%. But what does it mean? I can think of two things:

A) The BMU thought that, with the amount of energy added, SoC had rissen to 80%, but it turns out SoC has rissen to 85%. Same amount of energy adds 5% extra SoC, so capacity must be less than the BMU thought it was.

B) The BMU thought that, with the amount of energy added, SoC had rissen to 80%, but it turns out SoC has rissen to 85%. So, SoC at the beginning of the Charge cycle must have been higher than the BMU thought it was, so capacity must be more than the BMU thought it was.

C) ....

Any thought?

Also, usually we see the grid side power draw go to approx. 100 watts during the cell balancing phase(s). On the battery side, power is 0. Apparently, the 100 watts are consumed by the process itself. Every now and then I see power flowing out of the battery for a very very short time. Think of 53 - 55 watts. Just a little spike (unfortunately most likely to short for the Dog to pick it up). Just now, I saw a power draw of about 100 watts for several 10s of seconds. Never seen that before. What could that mean?

Final one for now. The tapering off at the end of the cycle seems not at a fixed moment in time. Right now, my SoC is at 90.8% and power fed into the battery (DC side) is still 2900 watts. Yesterday I saw it taper of as early as 80%. Must say, I believe it skipped the balancing at 80% and did one at 97% or 98% instead.

- edit -
The charge has finished at 104,98% (27.6 Ah out of 26.3 Ah). Just 2 hours later I initiated a top-up charge so my adapter would wake up and I could check soc again. Went down to less than 98%. By the time the top-up finished it was still less that 99%.
 
How accurate you can monitor the charging current via OBD2 ?

The DOG, apparently can't report anything below 1Amp ... so even monitoring the full charging process, there will be too much error if the charging current is integrated over the time

But, if you can monitor the charging current at 0.1A accuracy ... then you should be able to integrate this current and have a precise number of Ah which get push into the battery while charging.

Only in this way you can know if the SOC above 100%, is due to the fact that the battery got more Ah then expected by the SOC % delta + SOH .. or for some different type of estimation error.

PS: In my case, today, I got the SOC above the real (similar to how reported time ago) ... the DOG reported my morning trip to be started with 33.1Ah and 4.05v max (97.9% SOC) .. after a 10min pre-heat via keyfob hack ... since car was not charging while pre-heating at best the SOC should have been 31.6Ah ... but I also doubt that the car got charged up to 35.3Ah .. so ... it must be that sometime the SOC don't count in the pre-heating ... sometime .. since sometime it is looking it is properly counted inside the SOC (even when this is activated by keyfob hack)
 
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