Could be some outlier bad cells. I have 2 banks of these and I pull ~0.4c all the way down to 20% soc w/o any issues.
Anyone buying these 305ah envision cells?
- Thread starter G00SE
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SupraSPL
Solar Enthusiast
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2 previous packs of Envisions (305s 306s and 308s) from 18650 battery store, taking in 33A from the MPPTs. I don't think they ever have to put out more than 50 amps in this system and they perform without a hitch.
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Got them wired up charging now
3mm bloated +-
I’m curious when fully charged i wil do a top balance by wiring them parralel again..
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houseofancients
Solar Wizard
You didn't compress/fixate them, they will bloat more
3 times with strong tape and insulation boards between
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houseofancients
Solar Wizard
That is not properly fixating them, but better than nothing
houseofancients
Solar Wizard
Compression : did you ready any spec sheet ?
Fixation isn't even a discussion point
Zwy
Emperor Of Solar
Point me to the evidence.
I never have swelled cells, I always use compression. Side benefits of compression- no terminal stress, no creep on busbars which could cause a loose connection, no shifting of cells, cells remain close in temp to each other. There are more but those just come to mind quickly.
As for cell life, yes, I believe proper compression will extend lifespan/cycle life.
It does expend lifetime for sure
But for my use it’s not possible to compress it wil have a 400-700 cycle in 10years so i don’t care if it’s losing lots of capacity i make a new one
Putting it in a hardcase with no space around for compression
Using it for bellyboat fishing and compressor coolbox inside my vivaro with solarpanel on top to charge one of the few batteries i build
Those envision will be for the car 95% of the time..
I know people use them outside a fixture - I wouldn't. All my cells are in a fixture (i.e. compression, but that's a wrong term really, gives people the idea they need to torque the thing down like crazy). Fixture: nuts hand tight. I've recently rebuilt my pack since I changed enclosure. This is a cell after almost 4 years, in use 24/7, sitting at 100% state of charge over summer and cycled, and sitting at low state of charge most of winter:
diysolarforum.com
LiFePO4 cells in use since 2020. Bloating? Capacity?
As some of you may know, I'm in the process of moving my batteries into a new enclosure. Reasons: it's more organized, space is better optimized, and I can add more batteries more easily later if needed. This is the first time I took these apart since I built them somewhere early 2020. I bought...
diysolarforum.com
I’m wondering whether it would be more accurate if the term compression was dropped by the online community, your thread above is a good irl assessment of a battery pack being “ rigidly held in situ “... as opposed to being “ under pressure “... but as usual there will be as many opinions as humans on the subject.. I think you’re absolutely correct that compression gives users the wrong idea..?I know people use them outside a fixture - I wouldn't. All my cells are in a fixture (i.e. compression, but that's a wrong term really, gives people the idea they need to torque the thing down like crazy). Fixture: nuts hand tight. I've recently rebuilt my pack since I changed enclosure. This is a cell after almost 4 years, in use 24/7, sitting at 100% state of charge over summer and cycled, and sitting at low state of charge most of winter:
LiFePO4 cells in use since 2020. Bloating? Capacity?
As some of you may know, I'm in the process of moving my batteries into a new enclosure. Reasons: it's more organized, space is better optimized, and I can add more batteries more easily later if needed. This is the first time I took these apart since I built them somewhere early 2020. I bought...
Q-Dog
¯\_(ツ)_/¯
Manufacturers spec sheets I read say the cells should be "constrained" ... didn't say compressed. I gave up argueing with folks about it a couple of years ago when I started seeing all the rediculous spring contraptions people came up with.
houseofancients
Solar Wizard
the short naming for that would be fixation ;-)
Fixation doesn’t really describe in detail what it actually is... same as compression... neither of them are descriptive enough ... hence my more accurate term... fixed rigidly in situ... although I’m sure there is a much better term.. or maybe the forum members could come up with something ... what do you think HOA..?
houseofancients
Solar Wizard
Lol... cmon.. we can’t rely on dictionary... we can do better than some old musty book... we should at least have a glossary of descriptive terms for the forum... fixation means zilch unless it can be expanded further to suit the context.
True... however the compression is coming from the cells... not from the cells enclosure as of when it was built...
