Good luck with that plan, prices have been same for last 4 years and are now climbing like they are on TURBO !!
it seams when oil get cheaper Lithium goes into turbo - strange.
I'd be more worried about the present cost of LFP, if I was in real need of some new batteries. But, the cabin off grid batteries are doing fine; we were there this past weekend and even with the foreshortened winter days they reached float each day. The trailer has almost new GC-2's. So, I'll worry about costs in a few years time, with any luck.
Re
IF I understand LFP correctly you can safely use about 80% of the LFP's capacity. That allows for never running the voltage up to the maximum and never running them down too close to the bottom end. So the equivalent of a 300 AH FLA would be something like a 180 AH LFP. More or less. We can select parts and build our own battery if we dare or care to. As well as the need to find some prismatic cells in the range of 180 AH (3.2 volts) we would need a BMS. I recently ran into an experimenter who has bought cells and BMS from these guys.... http://www.electriccarpartscompany.com/ They have prismatic cells and BMS parts for sale. The user has to fabricate the cell enclosure that is needed. I am not endorsing the company, just passing along a link that some local crazy guy tinkering with electric vehicles thought used as a supplier. ...... about $250 for one 180 AH cell. Ya' need 4 plus the BMS.... probably another couple hundred bucks, depending on desired charge/discharge amperage capacity. Plus a battery charger or charging system.Ok, let's assume I want 300ah of nominal 12V capacity at 50% dod. What lithium cells would get me 150ah of usable power? Links please