Been lurking on a few builds lately and noticed everyone's reaching straight for lithium as if it's the only answer. Got me thinking about my own situation on the narrowboat — where I genuinely need the depth of discharge and cycle life — versus what a mate of mine is doing in his Transit camper.
He's mostly doing long weekends, plugs into hookup at least half the time, and his loads are modest: a 12V compressor fridge, phone charging, a few LED strips. Total daily draw probably sits around 40-50Ah on a heavy day. He was being talked into a 200Ah Fogstar Drift LiFePO4 setup (not a cheap option) when honestly two decent 110Ah AGMs from Elecsol and a basic Renogy MPPT would likely do the same job for a third of the price.
The lithium argument always comes back to weight saving and cycle life — fair enough on a boat or full-timer rig — but if you're racking up maybe 40-50 weekends a year at most, even a budget AGM bank will last you years before the cycle count becomes a real problem. The maths just doesn't stack up the same way.
Curious whether others have actually run the numbers on their use case before going lithium, or whether it's mostly become the default because it's what gets recommended on YouTube builds?