Fixing an APC battery backup that had dead batteries with aftermarket ones saving $$$

This is the APC Back-UPS NS 1350 battery backup. When the batteries die they tend to take the backup with them. The fix is replace the batteries with new ones. There are some risks involved, but if you are willing to get hands on you can replace the batteries for $40 instead of $70-90. The hard part is taping the batteries back together. This pack is used in several other models according to the APC website. BN1080G, BN1250G, BN1350G, BR1000G, BX1000G, BX1300G, BX1350M, SMT750R2-NMC, SMT750R2X122, SMT750RM2U https://www.apc.com/us/en/product/APC...