Well, Jeez, you could of at least said "Welcome." Lead may be dead in your calculator, but mine ran something like this: Cheapest decent Lifepo4 from a reputable seller was $230.00 for a 36V, 12 AH at 8.5 lbs. Dead lead was $58.00 for a 36V, 8 AH at 15 lbs. delivered.
So Not needing the extra 4...