[Znuff]

Hello,

A friend of mine with a 530e has had to replace 2 (out of 6) battery modules.

Ever since then, his hybrid battery never really seems to be charging to the cells full capacity.

We were looking online for discussions about similar problems, and we found a reddit post where someone has answered:

You need to perform a HV battery capacity test in order for SME to relearn new values from the cell module replacement or perform multiple charging and discharging cycles

We don't seem to have an ABL in my i5тд (4.39.20) to do such a thing, I only have these:



We looked into the "Start-up ..." / "Starting up...", but those seem to either require a code from an EoS tester or an EoS tester just to start it up. Obviously I do not have such a thing.

We searched a bit more online, and we tried a few different i5тд versions but we couldn't find any versions that have such an ABL.

After reading everything we could online, and even asking Gemini / ChatGPT etc. (that didn't help) to get some other opinions, the only thing that seems clear is that the cell modules would require charging/balancing OUTSIDE the car.

So I'm hoping someone is kind enough on the forum to offer a 2nd/3rd opinion.

Here's what we know:

Cell modules #3 and #5 were replaced, and they have WAY higher voltage than the rest:



Some individual battery cells are way lower voltage than the rest, there's a delta of about 0.132 V.



From what I understood online, the battery modules do have a way to balance the cells out a bit, when there's a very small delta and the car is idle, but our cells delta is too large to be corrected.

We do not know if the repair shop my friend went to registered the new SёяїдL of the battery modules in the SME. They said they are buying an EoS tester and that my friend should come back when they do... but they stopped answering his phone calls...

So my final question is: Is there any way to re-balance the cells, with i5тд or something else, that DOES NOT require taking out the batteries out of the car? Is there anything to be done in software to fїж the cell charging percentages?

Thank you.

[Dany]

Hello,

From what I know, the cells modules must be balanced and charged outside the car before installation at the same level as ones remaining in your battery pack... Even at the dealer with new modules, it is the procedure... Now about the SME reset, it is correct that you do need EOS tester to check everything and then the tester will give you an unique security code to put in the ABL in i5тд to validate the cells replacement. I know some poeple don't do this and buy a new SME module instead, it could be a solution but again, you need to open the battery pack. I seen some offering "solutions" to reset your own SME but never clearly seen someone saying it is 100% working.

[oceandiver86]

The SME can balance the cells itself to a certain level.
Charge the HV Battery fully and then lock the car and leave it for 72 hours.
However in this case the cell voltage difference is propable too much and balancing need to be done outside the car.

Additionally to what we saw on these cars with 2 modules out of 6 replaced, you will never get good range out of it anymore, usually replacing all cells as a set is the only feasible option to restore full performance.

You can try the i5тд capacity test, it would be under function structure/ testmodule and not under 5ёяvїcё functions.
It may help to improve range to a certain level but pls be aware, if the test aborts for any reason (connection, issue in HV battery detected etc.) it will lock the battery and you need to perform EOS test and initial startup to get it going again.

[DEJMIEN]

This is how I balance the battery every time I run the test in i5тд. Just hook up a 12V power supply and the HV charger, and turn on all the loads. i5тд will basically run a cycle to drain the HV battery and then charge it back up. The whole process takes around 4 to 6 hours.

[Znuff]

The SME can balance the cells itself to a certain level.
Charge the HV Battery fully and then lock the car and leave it for 72 hours.
However in this case the cell voltage difference is propable too much and balancing need to be done outside the car.

The cells were replaced quite a while ago (almost 2 months ago? I think?) and the car has sat idle for a long time -- it's mostly a weekend/tripcar at this point, so I'd think that should have been done already by the car. You're most likely correct that the difference is too large, else it would have been done until now...

You can try the i5тд capacity test, it would be under function structure/ testmodule and not under 5ёяvїcё functions.

Will look into that.

This is how I balance the battery every time I run the test in i5тд.

Which test/ABL?