i am also facing battery issue, contacted aldo cube, asking 60$, thieves. Found a battery store on Aliexpress, emailed them for this type. lets see what they respond.
What do you intend to do with those cells? Solder then in series and then what? You need a balance to make sure you are charging both cells at equal rates. Unless I am missing something, buying two of those cells from aliexpress is not gonna cut it without some sort of voltage regulation.
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