Sourcing parts
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Hello all, I'm trying to gather parts but I'm not sure about some of the suppliers/products I have an eye on. Could you maybe give me some feedback about the following products? (I also added more specific questions to the screenshots).
Also, do you have any good sources for the chemical reagents that are accessible to amateurs?
Did I understand correctly that there is a 12V and a 24V version with vastly different prices? The 12V one is 17€ while the 12/24V one 68€?
Many thanks for your help!
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Thanks for posting! About your material choices.
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First one is ok for the silicone gasket material. Get 0.5mm silicone, which is the one we have tested.
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This is not adequate. It needs to be conductive graphite felt. For example this one. We use 3mm so the best deal would be the 3x200x1230 one piece.
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That is the correct link for the pumps. Make sure to get the KPK200 24B motors. Send them a message after you make the purchase to specify the pump. Make sure to be clear about needing the specific pump model because you have a project with dimensions for that specific pump. They have sent me more expensive pumps in the past because these were just not in stock. Tell them it HAS to be KPK200 24B. These pumps are expensive (probably close to 70EUR each), the cheaper versions just don't work for this purpose. Trust me, we tried every pump tier starting from 3EUR and this was the cheapest pump that would run reliably without getting killed by the chemistry or the stress of running continuously pumping the higher viscosity fluids. Cheaper pumps are not strong enough to compress the chemical tubing and the softer tubings leak active material that destroys the pumps at the contact points.
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This is not adequate, it has to be a graphoil sheet. Like this one. We have routinely used 0.5mm sheets. Graphoil used to be readily accessibly through Aliexpress, but China has recently banned the export of several carbon based materials, including graphoil. Alternatively thin Titanium foil could also be used as an electrode material for the cell. Even 0.1mm Ti foil should be adequate (like you can find here).
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This is not the proper tubing. The specific tubing from Kamoer we ordered (which is a PTFE lined BPT), is called "Tygon Chemical tubing" by them, they don't have an Aliepxress link for it but if you contact them directly they can sell it to you. The closest tubing they have a link for would be this BPT (here). The diameter would be 4ID 6OD.
Let me know if you have any other questions!
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@danielfp248 thanks so much for the comprehensive write-up. I had hoped to be more accurate :D. Maybe you should have those links in the BOM page.
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@danielfp248 thanks so much for the comprehensive write-up. I had hoped to be more accurate :D. Maybe you should have those links in the BOM page.
@sepi Thanks for your reply! We would love to, but sadly Aliexpress/Amazon sellers change their links every few weeks (my guess is to stay relevant with the search algorithm of the platforms), so if we added them they wouldn't work in a month.
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@Vorg I did my homework and research the material but sourcing mostly industrial use material can be challenging as an amateur. Especially since the manufacturer in this case is from the USA and I'm in Europe.
@sepi said in Sourcing parts:
@Vorg I did my homework and research the material but sourcing mostly industrial use material can be challenging as an amateur. Especially since the manufacturer in this case is from the USA and I'm in Europe.
We strongly sympathize with you on this front! We've tried to make it as sourcable and low-cost as possible, but this has it limits.
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@Vorg I did my homework and research the material but sourcing mostly industrial use material can be challenging as an amateur. Especially since the manufacturer in this case is from the USA and I'm in Europe.
@sepi We are in Europe and we sourced everything as private individuals, so it can be done! Let us know if we can be of any additional help.
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About the triethylene glycol: can it be substituted for some other glycol maybe? I find it slightly hard to find. What's its purpose anyways?
@sepi No, it absolutely has to be triethylene glycol. Other glycols won't work, its chemical structure is exactly required to stabilize I5- in solution. If you're in the EU, you can get it from laboratodiumdiscounter in the Neatherlands (https://www.laboratoriumdiscounter.nl/es/trietilenglicol-99-extra-puro.html). It is not very expensive, 1L is like 15 EUR.
It's main purpose is to stabilize higher order polyiodides in solution and therefore prevent solid I2 formation at high SOC values. However if you don't go to high SOC values (keep the battery charge state low, then you can do without it).
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Ahh, excellent. Thanks for both the new reagents source and the explanation. ChatGPT told me that Propylene glycol might work, but then again why trust it :).
@sepi It doesn't, propylene glycol was also tested on the research paper that found triethyleneglycol worked. You need a very specific structure to stabilize the polyiodides.
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@danielfp248 i just received the tubing and I think I ordered the wrong one. I guess I didnct read correctly what you wrote to me about it. I got PharMed BPT tubing that is not lined with teflon/ptfe. Am I correct that I should order the teflon lined one explicitely? Also how did you know that the one I originally wanted to order (as seen on screenshot) is not good?
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@danielfp248 i just received the tubing and I think I ordered the wrong one. I guess I didnct read correctly what you wrote to me about it. I got PharMed BPT tubing that is not lined with teflon/ptfe. Am I correct that I should order the teflon lined one explicitely? Also how did you know that the one I originally wanted to order (as seen on screenshot) is not good?
@sepi The pharMed BPT is not the correct tubing. It will work for a while but will slowly leak iodine at high SOC values (especially above 50% SOC). You should order the teflon lined one explicitly, they refer to it as "tygon chemical tubing". Make sure to confirm they are sending you PTFE lines tubing. As I mentioned they do NOT sell this through aliexpress so you will need to contact them directly.
Note that you can still run tests at lower SOC values with normal BPT tubing.
