I figure I will chime in here due to my experiences.
When I first wanted to go from Lead Acid (Rolls Surette S-550's) to Lithium based systems, I explored many things for quite some time. I considered using either Tesla or Volt EV Packs and so on, so I ran the gamut of possibilities. In the end and working the number's I decided to buy a Pre-Built pack from ShunBin (link in my signature) and THAT was a $3,000 disaster ! plain & simple, it's covered in the thread mentioned. They are an example of a Shlock Vendor who uses Used Cells to make packs and flog them.
For Pre-Builts, you need to look at Battleborn, Relion, Delphi and even Victron, Trojan & Rolls have LFP Batteries now. All of these are far from cheap but they are exactly what you pay for and they do stand behind their products and have very good warranties.
After recovering from the ShunBin disaster I decided to DYI my own.
I paid
$3,000 USD for the ShunBin 24V/175AH with crap BMS & Used cells. Was advertised as 24V/200AH.
I bought 16, 280AH LFP cells from Xuba Electronic
Link to XUBA Alibaba Store which cost me
Total Order Amount: USD 2,433.32 including the Shipping fee: USD 1,110.60. That was Pre-Covid and Air Freighted DDP (Duties/Taxes paid). From that, I build two 24V/280AH Packs and used one Chargery BMS8T per pack which I believe were about $140 ea) with relays & delay board. * So for the cost of ONE ShunBin of Used Crap, I built 24V/560AH with new Grade-A EVE 280AH cells.
* I have since abandoned using their Electro-Mechanical relays which are energy pigs and am now using TE/Kilovac EV200AAANA Energy Saver Relays and Dongya DHV200AAANH Energy Saver contactors which are twice as efficient and do not waste power through heat. Used TE/Gigavacs sell on EBay / Amazon between 25-50 USD, New ones run around $125+ each. Th Dongya's are Made to Order and typically a minimum of 100 pcs, I got lucky and managed to get some samples but they are available from a few retailers.
REFS:
Dongya Electronics Link 1 Dongya Electronics Link 2 If you're interested, the DHV series is NOT LISTED but they can make them up, they are almost identical to the DH200 series BUT are A) Energy Savers & B) Bi-Directional (most important) They cost me $30 USD ea + S&H& Duties/Taxes.
One link of many for TE/Kilovac Relays on E-Bay COM. $39.99 USD But with shopping it you can find cheaper too.
Chargery BMS link for reference, it may not be what you want/need but here for reference, in any case, to make it easier for people looking to learn more.
http://chargery.com/BMS8T.asp There are many good BMS' out there that people are using wit great success BUT there are also some pretty crappy ones too, we have several threads on varius Known Good BMS' so the info is here if you look for it.
Hope this helps,
Good Luck
Steve
