My build (very slowly progressing)
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@sepi If you have an assembled cell with everything except the pumps you can use a syringe to manually pump some liquid through and see if you have any obvious leaks. This is how I normally test cells before I put activate material inside them or cycle water through them using pumps.
@danielfp248 Good trick, now I only need a syringe.
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My Mystat finally arrived, yay! No I need to figure out how to flash that pic (hopefully no programmer neede) and get rid of the remaining 5 PCBs.
@sepi You do need a programmer to flash that. We use a PcKit3 programmer.
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@danielfp248 noooooooooooo. I'll add: replacing it with an esp32, to the list of projects I will never do.
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@danielfp248 noooooooooooo. I'll add: replacing it with an esp32, to the list of projects I will never do.
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Yay, I got my MyStat working (a least to some extent). After fiddeling a bit with the yucky Microchip ISP software of which I had to install an outdated version (3.20 afaik) because they removed PicKit3 support, I finally managed to program Kirk's firmware on the device. Getting to run the python host software was fortunately pretty easy.
At first I was a bit stumped by an error message about an out of range current which I tried to calibrate away. It only occurred to me a bit later to connect the main PSU, which corrected the issue
Unfortunately I have some issues with commands that don't go through like the one for saving calibration to the device returning '?' instead of 'OK'.
Any Idea @kirk ?
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I am less familiar with the MYSTAT hardware/firmware, that repository is a fork and you can see the original developers efforts much before mine! Just to say I'm not super familiar, @danielfp248 programed mine and sent it to me in the mail
Yes, the main PSU needs to be connected for current measurents to function.
Also a warning, make sure the MYSTAT is completely powered off and unplugged before inserting/removing the measurement cable to the MYSTAT, otherwise there is a risk of damage.
Are you following the calibration procedure from the original paper with a (IIRC) 1k resistor?
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I am less familiar with the MYSTAT hardware/firmware, that repository is a fork and you can see the original developers efforts much before mine! Just to say I'm not super familiar, @danielfp248 programed mine and sent it to me in the mail
Yes, the main PSU needs to be connected for current measurents to function.
Also a warning, make sure the MYSTAT is completely powered off and unplugged before inserting/removing the measurement cable to the MYSTAT, otherwise there is a risk of damage.
Are you following the calibration procedure from the original paper with a (IIRC) 1k resistor?
Also actually @danielfp248 made all the code improvements to the repository for MYSTAT, he just dislikes Git and so I'm the one who uploads them
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Also actually @danielfp248 made all the code improvements to the repository for MYSTAT, he just dislikes Git and so I'm the one who uploads them
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@czahl ah I think @danielfp248 would know this answer, he has flashed most of the firmware but I don't remember him saying he made any changes. He is traveling right now so it may take him a bit to get back to us. I have only used the MYSTAT, I haven't dealt with the firmware myself. If he made any changes then we can push them to the repo ASAP.
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@czahl We have never updated the firmware, we use the same one as the original mystat paper. Errors when saving calibration are often related with the calibration parameters being of the incorrect numerical type or the values being too large. There might be a bug in the UI around this. I'll check when I'm back from my traveling, however I dont remember having issues saving these values when calibrating successfully with the 1k ohm resistors.
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@czahl We have never updated the firmware, we use the same one as the original mystat paper. Errors when saving calibration are often related with the calibration parameters being of the incorrect numerical type or the values being too large. There might be a bug in the UI around this. I'll check when I'm back from my traveling, however I dont remember having issues saving these values when calibrating successfully with the 1k ohm resistors.
@danielfp248 said in My build (very slowly progressing):
We have never updated the firmware, we use the same one as the original mystat paper
Are we talking about the same mystat repo? Again in my understanding this paper reflects the PCB from PcbWay, und this has the 4 reed relais (on top of the picture) for the 4 current ranges. In the main.c only the original 3 are handled.
Somewhere there is a mismatch, or am I'm looking into the wrong repo?
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@danielfp248 said in My build (very slowly progressing):
We have never updated the firmware, we use the same one as the original mystat paper
Are we talking about the same mystat repo? Again in my understanding this paper reflects the PCB from PcbWay, und this has the 4 reed relais (on top of the picture) for the 4 current ranges. In the main.c only the original 3 are handled.
Somewhere there is a mismatch, or am I'm looking into the wrong repo?
@czahl I dont know which files kirk used to create that repo. I use the firmware directly from the repo linked on the mystat paper.
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@czahl I dont know which files kirk used to create that repo. I use the firmware directly from the repo linked on the mystat paper.
@danielfp248 Thanks for the hint this is the reason. In the version referenced in the paper, the firmware is extended to support the 4 current ranges.
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@czahl We have never updated the firmware, we use the same one as the original mystat paper. Errors when saving calibration are often related with the calibration parameters being of the incorrect numerical type or the values being too large. There might be a bug in the UI around this. I'll check when I'm back from my traveling, however I dont remember having issues saving these values when calibrating successfully with the 1k ohm resistors.
@danielfp248 said in My build (very slowly progressing):
however I dont remember having issues saving these values when calibrating successfully with the 1k ohm resistors.
I need to actually do the real calibration when I find the time. I'l report back then.
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@danielfp248 I managed to get the mystat working correctly and calibrate it too. The problem was the firmware. I was using the one from @kirk's repo but that's the one working for only 3 current ranges. https://github.com/matthew-yates/MYSTAT/blob/main/firmware/firmware.hex is the correct one to use with the updated board. Should I create a pull request?
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@danielfp248 I managed to get the mystat working correctly and calibrate it too. The problem was the firmware. I was using the one from @kirk's repo but that's the one working for only 3 current ranges. https://github.com/matthew-yates/MYSTAT/blob/main/firmware/firmware.hex is the correct one to use with the updated board. Should I create a pull request?
@sepi yes, please do.
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After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
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After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
Congratulations on getting all the chemicals needed!
@sepi Let me answer your questions:
After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
When we run battery experiments we generally only run 5mL per side, 5mL on the catholyte side and 5mL of the anolyte side.
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
Clean with tap water, then clean with alcohol or acetone, then clean with a paper towel.
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
This depends on your local regulations, you should contact your local authorities to see what they require. You can precipitate everything in the solution by adding Cu carbonate (mainly potassium chloride would be left in solution), the insoluble solids can then be disposed of more easily. Storing solids is also easier as they occupy less space.
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Preparing the salts to +/-0.1g should be precise enough.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
For these amounts this is fine, for larger amounts (10x this), adding the salts to water would be more desirable.
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
It needs to be stored in an airtight container as the iodide in solution will react with atmospheric oxygen, it will turn yellower and then red as this happens. You can put a strip of metallic zinc inside the solution to better preserve it. About the ZnCl2, it is very hygroscopic, so you should open this container for as short of a time as possible. I try to weigh it in less than 20 seconds to introduce as little water as possible from the air.
Please remember to wear proper PPE when doing all of these experiments and make sure you do so in a place that's well ventilated.
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@danielfp248 Thanks for the quick and thorough answers! You should add those points to the docs unless you feel that this might potentially create legal trouble.
About the PPE, I was wearing nitrile gloves, cotton work cloths and plastic safety glasses (not closed though). I felt reasonably safe
About the copper carbonate for precipitation, would that be the natural one or basic one? Since I'm curious and want to bring my chemistry skills up to date: how do you know that this will cause precipitation? Is this compound used frequently for precipitation? Is this about chemical potential of copper iodide (s) and zinc carbonate (s) being lower than the sum of their respective ions (aq) in solution?
