Batteryclearing house.com often has tool battery packs.
just search the site for tool there are more there.
If i was starting a 18650 powerwall I would look at these ...
While the site is a good resource for the most part. The thing that gets me is they can't even get the abbreviation right. Case in point
afaik there is no Lithium phosphate4 chemistry right above this they mention Lithium Iron Phosphate from the looks of things they haven't update the Page in...
A single 18650 can put out many more amps than they are rated for. https://secondlifestorage.com/index.php?threads/what-is-your-short-circuit-current.97/ I believe Lithiumsolar did a yt on the dead chort amps of an 18650 but I couldn't find it.
Go 14s less stress on the battery many 48v inverters still are based on lead acid which can be near 60v down to 42v 14s gets you to 57.4v- 50.4v. The Less work the inverter has to do. 3.6v-4.1v
ESR (Equivalent Series Resistance) is the internal resistance present in any cell that
limits the amount of peak current it can deliver. In short IR
The IR reported by the xtar is calculated using the dc method iirc, it may not be as accurate as an IR meter such as the YR1030+,1035+, SM8812A...
Lithium Tinanate datasheet https://files.gwl.eu/inc/_doc/attach/StoItem/6991/LTO-40AH-CY_datasheet.pdf so LT) has many of the same properties as NiFe batteries. long life being the key one 30,000 cylce life time works out to be 82 years<edit>@1 cycle per day. < first datasheet I found.
Lifetime as in 40+ years. http://nickel-iron-battery.com/ Nickel Iron battery often lasts in excess of 40 years
off grid in Chicago 2001 http://nickel-iron-battery.com/Nickel-Iron-Solar-Chicago.pdf don't know if this guy is still around but interesting reading
If the wire is plated with silver (not nickel plated or tin plated) the wire will likely conduct more Amps as silver is one of the better conductors. So will conduct higher Amps before heating up in theory.