Originally Posted by EVfun
You are a bit optimistic on the Watt hours per cell. They up to 4.0 volts at the end of charge, but when the charger is removed they will fall back to 3.4 volts. The nominal cell voltage (no load cell voltage) falls with the state of charge, down to 3.3 volts before 10% of the charge is used, and then almost steady at 3.3 volts until the last 20% where they start falling again. They also sag some under load. I'd recommend using 3.1 volts for just shy of 2 kWh from your proposed pack.
In that case, then, I'd need even more of them. But the LiPo batteries may be able to provide a lot more of their stated A-Hr capacity (as translated to W-Hr) than a similar Lead-Acid battery. For automotive use, I think the LiPo batteries are the best way to go, if you want to use the vehicle for the usual everyday commuting and household use.
But for homeowner tractors, or for inexpensive conceptual automotive prototypes, the lead-acid batteries may be OK, especially if you can get by with no more than 4-6 of them and boost the voltage.
I found a thesis paper that mentioned new research on aluminum batteries that have the potential to provide 10x the storage capacity of Lead-Acid. But it seems they are not rechargeable, although there are still possibilities of using replaceable electrodes:
I'd hate to invest a pile of money in LiPo that will last for 5-10 years and then two years doen the road there's a huge breakthrough!