prices seem to be going up.
a few years back i remember figuring that lithium iron phosphate batteries had hit par with lead acid for life cycle cost effectiveness, unfortunatly i've lost my notes on pricing.
seems thundersky still wants 1.5$/ amp hour for 3.2 volt LIFEPOH which actually works out to 2.1 watt hours per dollar at a cell voltage of 3.7 volts.
cheapest i can find online at this time for lead acid cells is 8 watt hours per dollar here at battery sharks dot com for the 3 5 amp hour 1 2 volt cell.
that's 52$ or just over 2$ per pound.
i made an excel chart and graphed out the watts per dollar and its actually about a straight line, flattening out a bit at 7 watt hours per dollar and then after 6 watt hours per dollar quickly growing more expensive as the batteries get smaller and more specialized.
now that being said it is very easy to find sealed lead acid cells batteries for the same price as lithium iron phosphate cells for the smaller cells, a complete rip off.
the reason i'm posting is 8 watt hours per dollar seems to be a bit too good to be true, or are they just trying to move those batteries?
basically i'm looking to buy some sealed lead acid cells for various robot projects or something, but i'd rather not get screwed by buying the cheapest batteries i can find.
i've made that mistake twice in a row now buying car batteries from walmart.... they last about 2 years.
