18650 house battery?
hoping that there are some DC electronic gurus here that can help me with my question:
I have built a lot of large 18650 batteries in ebikes. I am considering building one for my RV to replace the SLA. they do not have the life cycles of a Lifepo4 but they are substantially cheaper for a home build (dont do this with out experience), and they still have far more life cycles than SLA with much better performance and far less weight.
so anyway, I can build a 18650 pack with comparable capacity to a house battery SLA for about $235. (600 whr of useable capacity). I would probably triple the capacity to about 1800 whr for the build but its substantially cheaper then Lifepo4.
so my concern is the voltage.
My SLA house battery Tops out at around 12.9v. the closest that I could get a 18650 to is either 12.6 for a 3s config or 16.8 for a 4s build. It gets a little more complicated then that as well because some cells like to retain more of their capacity in different voltage ranges so if running on a 3s setup on my current choice cell, I get %50 of my capacity between 10.8v and 9.9V.
I would obviously have to add a charger in line with the converter for charging because these batteries do not like to be overvolted when charged.
My question is the 12v system of the RV. how much voltage variance do these appliances typically work right with? water pump, slides, furnace, jacks, lights water heater, fridge and such? there are ways to deal with these voltage dips if some of these appliances/systems do not like lower or higher voltage however, they come with trade offs and there is a point where its just not worth it.