Cosmo wrote:I am eager to get a Lithium. For me the show stopper has been charging in below freezing temps.
Are you in warmer temps or have you solved this?
With the cabin installation, the lead-acid batteries were stored in an add-on compartment outside at the service panel end. That was enclosed and roofed but not airtight and not insulated, heated or cooled. The lithium cells take up less space than the lead-acid, but as you point out Cosmo, they cannot be charged when the battery is below freezing.
One solution would be to do like Tesla and the Chevy Volt. They have water passages running through the battery and they can heat or cool depending on the need. My solution was to move the lithium cells indoors. I built a cabinet on the inside of the wall where the lead-acid batteries were stored. The LiFeMnPO4 cell packs are located in that. Cabinet sides have screens on two sides as well as a door. There is a fan I can use to circulate air within the cabinet. I have several temperature sensors inside the packs with a readout on the cabinet end. When we arrive there if the pack temperature is less than zero C, I do not charge them. It only takes a couple, maybe three hours to get the interior warm. I did not package my cells together in a big battery pack but made groups of two cells. That leaves more cell surface area open and the cells warm more quickly. We don't have a problem with overheating the cells. The cells we have can be discharged down to -20 C (-4 F) but need to be above freezing to charge.
FWIW, lithium batteries can be used in motorcycles, ATV's and the like in freezing weather with no cold temperature concerns, IF one does something that seems a little weird at first thought. Before starting (electric start) you need to turn on the headlight and draw off some power. That causes the battery to self warm. Then the Li battery puts out enough voltage / power to easily crank the engine. The warmed battery can also then accept charge input from the alternator. If you don't turn on the headlight for a few minutes first the battery is cold and cannot supply enough power to crank the engine.
FYI, the prismatic cells like I used have some sort of plastic cases. Under some operating conditions they may swell. That is not good for them. The cells are usually assembled into packs of four or more cells. Aluminum or steel plates are used along with straps of some kind or threaded rods to make a unit that will not swell.