Following your documentation – feedback & questions
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It is incredibly exciting to see you guys reproducing the kit! We are really excited about completely independent third parties being able to just build and run this thing.
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@sepi , thanks for the kind words. @danielfp248, @kirk It is really cool that you have done and made this project available! Building and testing it personally is an experience much more valuable than just reading an article.
I'll be honest — before the first test, I was a bit worried that a leak might suddenly appear.
I'm also glad, @danielfp248 , that you confirmed the accuracy of my results.
I'm looking forward to seeing your project develop!
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Hello everyone! It’s been a while
I’ve returned to testing the flow cell and even built a second one to check repeatability. I’m wondering what could cause such a large difference in performance between them. The second cell showed only 0.85 V during discharge (compared to 1.15 V for the first one).There was also a warning during the discharge of the first (better) cell:
“The command b'RANGE 2' resulted in an unexpected response. The expected response was ‘OK’; the actual response was ‘WAIT’.”
After closing this warning and restarting the charge/discharge cycles, the system no longer stopped charging the cell at 10 mAh as before. I manually stopped the cycle at 22 mAh.
The cell was left in the workshop, and I was remotely connected from home to the Raspberry Pi controlling the pumps and Mystat. The next day, when I returned to the workshop, both tubes from the pumps had detached from the cell, and the electrolyte had spilled on the table.
Do you have any idea what might have happened?I also wanted to ask whether you’ve tried different gasket materials—such as FKM (Viton) rubber or expanded PTFE (ePTFE)?
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@gus afaik, the firmware from kirks repo with the python mystat application is not actually the latest one (it's missing the extended range). Check the updated page on the mystat docs: https://fbrc.codeberg.page/rfb-dev-kit/pstat.html which links to thw correct version. I'm not 100% sure if that is the issue you are encountering but it might be.
Concerning the detached tubing, I could imagine the felt getting clogged somehow leading to an ovepressure making the tubes pop off. I'm having some issues with gas being pulled into one container, leading to pressure buildup in the container. I have no clue yet where this comes from.
Good luck with your further investigations! You might want to rzun your future experiments in a transparent PP box in the future. I will for sure once I'm ready for actual electrolyte.
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Hello everyone! It’s been a while
I’ve returned to testing the flow cell and even built a second one to check repeatability. I’m wondering what could cause such a large difference in performance between them. The second cell showed only 0.85 V during discharge (compared to 1.15 V for the first one).There was also a warning during the discharge of the first (better) cell:
“The command b'RANGE 2' resulted in an unexpected response. The expected response was ‘OK’; the actual response was ‘WAIT’.”
After closing this warning and restarting the charge/discharge cycles, the system no longer stopped charging the cell at 10 mAh as before. I manually stopped the cycle at 22 mAh.
The cell was left in the workshop, and I was remotely connected from home to the Raspberry Pi controlling the pumps and Mystat. The next day, when I returned to the workshop, both tubes from the pumps had detached from the cell, and the electrolyte had spilled on the table.
Do you have any idea what might have happened?I also wanted to ask whether you’ve tried different gasket materials—such as FKM (Viton) rubber or expanded PTFE (ePTFE)?
@gus said in Following your documentation – feedback & questions:
I’ve returned to testing the flow cell and even built a second one to check repeatability. I’m wondering what could cause such a large difference in performance between them.
Hey, welcome back! As sepi said, please upload the correct firmware to the MYSTAT as an outdated version was previously present in the repo, also be sure to recalibrate your MYSTAT before cycling again, this is likely the source IMO. It wouldn't be bad to add some sort of calibration reminder/routine into the MYSTAT software...
@sepi said in Following your documentation – feedback & questions:
Good luck with your further investigations! You might want to rzun your future experiments in a transparent PP box in the future. I will for sure once I'm ready for actual electrolyte.
Definitely a good idea!
@gus said in Following your documentation – feedback & questions:
The next day, when I returned to the workshop, both tubes from the pumps had detached from the cell, and the electrolyte had spilled on the table.
Do you have any idea what might have happened?Ah shoot, sorry to hear this. I suspect if the MYSTAT was out of calibration it may have caused issues with the cycling. An issue with the iodide-containing chemistries is possible clogging of the felts with iodine if something goes wrong; normally the triethylene glycol should prevent this by forming a soluble complex, but it's possible your system got outside the normal operating range. I'd try again fresh (in a PP box/spill tray/secondary containment), with a calibrated MYSTAT running the latest firmware. Tagging @danielfp248 in case he has any suggestions.
