Clarification needed on copper thickness of inner PCB layers

[Selvakumar58]

In the PCB notes, we see the following text:

However, in the Board setup, the details are as follows:

Here the units are in mils, but when converted to um, we get:

105 um outer layers
35 um inner layers

Which is the right one?

Regards,
Selva.

[pasrom]

Hello @Selvakumar58,

Could you confirm if you are using the latest commit? I noticed that in PR #46 of the LibreSolar/bms-c1 repository, there doesn’t seem to be any difference. If you are not on the latest commit, it might be worth updating to see if that addresses your issue.

[Selvakumar58]

Hello @pasrom ,

We are using V0.3.3 (Commit no: b7895e0) to build a few prototypes before transitioning to the latest commit.

Any thoughts on the copper thicknesses for this commit?

Regards,
Selvakumar.

[pasrom]

From what I understand, @martinjaeger manufactures his boards with a 70 μm thickness for all four layers. It would be great if @martinjaeger could confirm this.

[martinjaeger]

Correct. We manufactured the first batch with 70u for inner and outer layer because the originally intended 105u were not suitble for the small pin pitch of the bq76952.

Both myself an @pasrom have tested the boards and 70u turns out to be sufficient for 100A with a heat sink.

[Selvakumar58]

Thank you