Anyone else finding it harder to get decent 12V leisure batteries lately?

Been noticing this for a while now across all three of my builds — the van, the loch-side cabin, and the old narrowboat. Sourcing decent 12V leisure batteries has become a proper headache.

The AGM market feels like it's flooded with rebadged mystery cells where the spec sheet and the reality are two very different things. Picked up a pair last spring that were supposedly 110Ah each. Capacity tested at barely 78Ah under any real load. Absolute joke.

LiFePO4 has obviously changed the game, and I've had solid results with Fogstar Drift cells for the van build — genuinely good quality for the price. But not everyone wants to rebuild their BMS knowledge from scratch just to run a few lights and a compressor fridge on a weekend away.

The traditional leisure battery sector seems to be coasting on brand recognition. Victron on the inverter/charge controller side is still rock solid, but the actual battery market below the premium LiFePO4 tier feels like a race to the bottom lately.

Wondering if it's a supply chain thing post-Brexit, or just manufacturers cutting corners because demand has shifted so heavily toward lithium?

Anyone else finding the same? Particularly curious whether folk with boats are having similar issues — marine applications seem even more exposed to dodgy cells given the vibration and humidity.

@LochWalker yeah the AGM situation is grim. Been running a mixed Victron/Fogstar setup on the narrowboat and honestly the Fogstar 12V lithium route has mostly sidestepped the AGM shortage for me — though the upfront cost is still a sore point.

What I'm actually seeing is the decent mid-tier AGM options disappearing. You've still got cheap rubbish flooding in from dubious sources, and the proper premium stuff at eye-watering prices, but that sensible middle ground — your Numax, Banner, decent Varta — seems to be getting squeezed out of stock constantly.

Suspect a lot of manufacturing capacity quietly shifted toward EV auxiliary batteries rather than leisure. Pure speculation on my part but the timing tracks.

Worth checking BatteryMegaStore for stock alerts — they've been slightly more reliable than the bigger names recently in my experience.

@LochWalker this mirrors exactly what I've been dealing with at the cabin. The mid-tier AGM market has basically collapsed into a load of rebadged Chinese cells with wildly inconsistent capacity ratings — I pulled 40Ah out of a "100Ah" unit last winter under load testing.

Honestly my advice now is skip the leisure AGM segment entirely. I moved the cabin over to Fogstar Drift LiFePO4 last spring and the difference in actual delivered capacity vs. rated is night and day. Yes, the upfront cost stings, but when you factor in cycle life over 5+ years it's not even close on £/kWh.

The other option worth considering is sourcing grade A prismatic cells direct from a reputable supplier and building your own bank with a Daly or JBD BMS. More effort, but you know exactly what you're getting.

Been wondering if anyone else had noticed this — glad it's not just me being picky.

On the narrowboat I've been going back and forth on whether to just bite the bullet and move to a proper LiFePO4 setup. The upfront cost with something like Fogstar Drift cells is still a sting, but if the AGM middle ground has genuinely collapsed as @WezWhite72 says, maybe there's no sensible reason to keep chasing it?

What I can't work out is whether 12V LiFePO4 drop-in replacements are actually reliable long-term on a narrowboat, given the vibration and damp. Anyone running them in that environment specifically? And do you need to upgrade the alternator protection side of things, or is a decent Victron DC-DC charger sufficient to keep the alternator from cooking itself?

Spent three days last autumn tracking down a decent AGM for the boat — ended up in a rabbit warren of conflicting specs, suspiciously cheap rebrands, and one eBay listing that claimed "marine grade" despite being photographed in someone's living room next to a labrador.

Eventually landed on Fogstar and honestly haven't looked back. The lithium jump was terrifying from a cost perspective but my Victron BMV-712 stopped lying to me about state of charge, which was a revelation.

@GoldenTinker the mid-tier AGM collapse is real — it's like the supermarket own-brand version of batteries. Nominally exists, functionally questionable.

Tiny house is still on AGM for now purely because the budget wept at me. But I reckon by spring I'll crack and go lithium there too. The marina gossip suggests I'm not alone in that trajectory.

CopperWarden | 847 posts | ⚡ Trusted Contributor

Worth mentioning something I've not seen flagged yet — the brand consolidation happening behind the scenes. Half a dozen "different" batteries on the shelves are now coming out of the same two or three factories with different stickers slapped on. The actual specs sheets are near-identical once you dig into the C20 ratings and internal resistance figures.

@BoxerWanderer the conflicting specs issue you're alluding to is often down to this — manufacturers publishing optimistic figures from the factory's generic datasheets rather than their actual tested units.

My workaround lately has been going direct to specialist marine electrical suppliers rather than general battery stockists. Slightly dearer upfront but at least you get someone on the phone who actually understands cycle depth and doesn't just quote you the headline Ah figure.

On my narrowboat I gave up chasing AGMs about two years back and went full lithium — Fogstar Drift 100Ah cells. Night and day difference, honestly. The sourcing headache just evaporated.

What pushed me over was a winter mooring in Middlewich where shore power was unreliable. Kept killing a decent-spec AGM through partial charging cycles. The Fogstar paired with a Victron SmartShunt meant I finally knew what was happening in my battery bank rather than guessing.

@LochWalker — for three separate builds I'd genuinely consider whether the per-unit cost of lithium starts making more sense than continually hunting down AGMs that are half what they claim on the label. The narrowboat conversion cost me more upfront but I've not touched it since, which on a boat is worth its weight in gold.