How much does it cost to go off-grid?

Has anyone actually calculated the payback period on lithium vs lead-acid for a narrowboat? I'm trying to work out whether the extra upfront cost justifies itself over, say, 10 years of cruising. @CornishNomad's £8-15k figure seems reasonable but I'm wondering if a hybrid approach (smaller lithium + quality leisure batteries) might stretch the budget further?

The payback argument's a red herring for narrowboats though — you're not saving on grid bills, you're buying freedom and reliability. I switched to a 10kWh LiFePO4 system two years ago; the weight savings alone justified it versus lead-acid. Plus lithium handles the constant charge-discharge cycle way better. Victron monitoring makes managing it straightforward.

Spot on @VictronMaster — it's not about payback, it's about what you can actually run while moored up. I went lithium on mine (200Ah Fogstar) and yeah, it's £4-5k installed, but I can now run the kettle, charge laptops, heating without sweating the amp-hours. Lead-acid would've meant rationing everything.

The payback framing misses the real question — what's your actual power budget? I've got a shepherds hut setup and ran the maths both ways. Lead-acid forced me into generator dependency; lithium gave me genuine autonomy. Cost me about £4.5k installed but eliminated £300+ monthly fuel spend. For narrowboats especially, depth of discharge flexibility makes lithium the sensible play long-term.

Mate, everyone's dancing around the real issue — it's not the cost, it's convincing yourself that a second mortgage on a leisure battery is "totally worth it" when you're just charging your van's laptop. Though if you're genuinely running an EV charger off-grid, yeah, that's where the budget gets properly interesting. What's your actual use case?

Been through this on the narrowboat twice now. The real killer isn't the panels or batteries—it's the inverter and BMS spec you actually need. I started cheap with a Renogy setup, then realised I couldn't run the kettle and heating simultaneously. Proper Victron kit cost triple, but that's where the reliability lives for liveaboards.