Lead Acid vs. Lithium: Lifetime Cost
If you compare lithium batteries to lead acid batteries Ah to Ah, lithium batteries are more expensive. But step back and look at the bigger picture – taking into account everything we`ve covered so far – and you can see how lithium batteries can actually save you money, time, and hassle in the long run.
Let`s look at some cost examples when designing a battery bank for a 12V system that uses 1400Wh a day.
Flooded Lead Acid vs. Lithium
The math is the same for a flooded lead acid battery bank as for a sealed one. So let`s again compare a 518Ah 12V lead acid battery bank with the 300Ah 12V lithium bank. I`ll round up to 675Ah to use the popular at $190 each. Using 6V batteries will require 2 in series to get 12V, so I`ll need 6 for a total of $1140. We are still going to use a KiloVault 3600 HLX+ for $1945, or I could use three KiloVault 1200 HLX+ 100Ah 12V batteries for the $745 each. Some people prefer installing multiple batteries in parallel for redundancy and find that the size and weight of smaller batteries may be easier to manage than one.
The price gap between flooded lead acid and lithium is greater than with AGM. With flooded`s 2500 cycles versus lithium`s 5000 cycles, a well maintained flooded battery bank can last half as long as lithium. But a poorly maintained flooded battery bank can quickly become a boat anchor in a year or two. So the flooded is actually a slightly more expensive solution than sealed lead acid at $2280 for two banks. Compare that to $1945 for our single-battery lithium option (or $2235 for the three-battery option). And again, you have the advantages of the smaller, lighter, safer battery bank, the higher current capability, and minimal maintenance needed on the lithium.