Alkaline
Solar Wizard
You used to be able to drill and tap them but that is no longer allowed by EVE...
EVE identifies Grade B cells using new marking Method [Reposting from General]
- Thread starter DSmartLife
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Alkaline
Solar Wizard
Andy has always stated he is learning as things go and tells people what he has learned along the way. I for one appreciate his honestly and willing to learn as many of us DIYers are in the same spot.
You need to watch that with more attention. He doesn't admit that he was wrong. He shows that his cells have expanded and it might be stressing the terminals.
At about 7' he assesses the swelling and considers it to be not that bad and refers to another youtuber who had restrained his cells and got the same swelling even though the cells were restrained.
IOW it's a click bait video title.
My understnding of his thoughts on restraint aren't that you shouldn't do it but that, in low current applications, the effect on cell longevity is pretty much irrelevant - you might only get 3000 cycles instead of 6000, but even that is likely to exceed the calendar life expectancy of the cells.
Have you seen such information for a LiFePo4 cell? I haven't seen this detail in the EVE/CALB datasheets.
PVs actually say that they will fade X% in 25 years. It would be nice if the same was available for the cells.
No, but that's not very surprising as the life expectancy of Lion cells is very strongly dependent on storage temperature and SoC so any figure is going to be inaccurate and potentially misleading.
PV makers tend to give (worthless) guarantees that the modules will fade not less than x% in so many years. They don't say that they will fade by that amount and usually you might expect that the output and usable lifetime will be much greater than that.
I found research that gives some direction for longevity. Basically, keep the at a moderate temperature (30C) and not fully charged (this has secondary importance).
My cells are working at 15C to 30C. The lower end is provided by the heating pads, the higher end is because of the current surrounding conditions (6cm heat insulation sheets and 10-12C surrounding temperature). In the summer I'll be removing the heat insulation sheets on top of the pack. And the pack stays mostly at ~40% SOC. Looks like I'm in the sweet spot for longevity.
My cells are working at 15C to 30C. The lower end is provided by the heating pads, the higher end is because of the current surrounding conditions (6cm heat insulation sheets and 10-12C surrounding temperature). In the summer I'll be removing the heat insulation sheets on top of the pack. And the pack stays mostly at ~40% SOC. Looks like I'm in the sweet spot for longevity.
augiedoggy
New Member
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- Oct 26, 2022
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So more recently he seems to believe the compression matters now... I agree he is learning and I totally respect that as we all learn as we go and make mistakes. But hes quick to form and share opinons based on incorrect assumptions like the series he did bashing the JBD 300amp relay bms that he himself damaged by changing setting incorrectly and causing the relay to quickly cycle on and off over and over bypassing the cooling time mechanical relays need to prevent burned and fused contacts. He then went on to explain those setting and the presets made no sense which to me made it clear he thought the mechanical relays could switch on and off quickly like mosfets with no tradeoffs. I love watching his stuff and value his input but I think he could benefit from being a little more cautious about what he tells people from time to time. He is quick to blame things.
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Alkaline
Solar Wizard
Those grade B hithiums look like they carrying twins..
Is the EVA foam shown in the video provided by Seplos, or is that something that Andy added?
Alkaline
Solar Wizard
foam is not a good separator material should be fiberglass sheets.
That is why I asked. Do any of you Seplos owners care to answer?
Alkaline
Solar Wizard
It hasn't' aged the prediction was made well early on that Chinese sellers would start to cover/up make fake qr codes. The only thing that has changed is that 2 or so years trying to determine the difference between genuine vs reject cells was much murkier.
houseofancients
Solar Wizard
seplos provides it for their mason kits by default, but you can purchase it through alix too
houseofancients
Solar Wizard
it isnt just foam...
and no , it shouldnt be fiberboard, as that will not allow for cell movement
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Thanks. Andy specifically mentioned EVA in the posted video. I'll surmise that he added it himself without reason or any sort of properties measurement on his behalf.
houseofancients
Solar Wizard
no, he is using the sheets provided, but next to a "squezy" eva side, there is a added thin plastic seperator behind the glue
Your two answers were confusing. Thanks for getting me straight.
I didn't see any mention of the properties of the EVA foam on the Seplos site; I guess we have no way of telling if they are doing compression the way cell manufacturers recommend. If EVA takes a set like I think it will over time, any compression could turn to zero as the foam hardens.
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