Modpack version
0.4.0
Describe the bug
When the server restarts, the ender cells lose all the energy cells that have been placed in them, making them not work.

Logs
Input pastebin link to crash-report or latest.log, if applicable.

Screenshots
If applicable, add screenshots to help explain your problem.

Thank you for the report, I will investigate the issue.

Was also reported to Powah by someone else later on here: owmii/Powah#158
I could not reproduce with just Powah alone though (see my comment with timestampped video).

It's possible it has something to do with updating from 0.3.x to 0.4.0, and thus changing worlds. That's what I had done, before this bug started happening.

Well, it could be due to my PR here owmii/Powah#155.
Which fixed servers having channels 2-12 being the same channel, so you effectively only had two channels that you could use.
But... I made sure to keep the NBT reading and writing output the same, but I might have messed something up?

Edit: I tested creating and setting up an Ender Cell with Powah-1.16.4-2.3.9 (released 2021-01-16), then updated to Powah-1.16.4-2.3.13 (released 2021-02-22) and it didn't lose max capacity or energy, infact it duplicated the channels 2-12 so free energy and capacity (which is to be expected since previously all those channels shared the same Energy object prior to the PR).

Okay yep, it was definitely my PR that fixed 3-12 sharing the same channel as 2.
Should be fixed once owmii/Powah#160 gets merged and released.