Anyone else finding lithium prices have finally dropped enough to make the switch worth it?

Been running a 200Ah AGM bank in the van for about three years now and honestly I've got my money's worth out of it, but it's starting to struggle — took it down to around 50% a few too many times over the winter and I reckon it's lost a fair chunk of capacity. Checked resting voltage this morning and it was sitting at 12.4V after a full night off the solar, which isn't great.

Had a look around and 100Ah LiFePO4 batteries have come down a fair bit lately. Spotted a Fogstar Drift 100Ah for around £179 and a couple of the Redodo/Enjoybot options on Amazon for even less. Two of those in parallel would give me the same headline figure as my current AGM but obviously I'd actually be using most of that capacity rather than staying above 50% all the time.

Has anyone made this switch recently and genuinely noticed the difference in day-to-day usability? I've got a Renogy 40A DC-DC charger feeding from the alternator and a Victron SmartSolar 100/30 on a 400W roof array — from what I understand I'd just need to tweak the charge profiles rather than replace anything. Am I missing any gotchas, or is this finally just a straightforward upgrade?

@Paddy78 — similar crossroads here but with a garden office and EV charging setup rather than a van. Been watching Fogstar's 280Ah LiFePO4 cells drop noticeably over the past 18 months.

My main hesitation isn't actually cost anymore, it's whether the BMS options have matured enough for heavier cycling loads. Anyone running a Daly or JK BMS under constant EV top-up demand? I'm essentially pulling irregular loads at unpredictable times and I'm not sure a budget BMS handles that gracefully long-term.

The usable capacity argument basically sells itself at this point — 100% DoD vs the AGM "real" 50% means the price-per-usable-kWh comparison looks very different now than it did even two years ago.

@Paddy78 made the jump last autumn — grabbed a 200Ah 12v LiFePO4 from one of the Chinese suppliers on here and honestly can't believe I waited so long. The usable capacity difference compared to my old AGM is night and day. What really swung it for me was the weight saving in the van, felt almost guilty how much easier everything got.

@LazyWarden for a garden office setup you'll appreciate not having to faff about with equalisation charges either. Just fits in nicely with a decent BMS and largely looks after itself.

Prices do seem to have levelled off rather than continuing to drop, so I wouldn't hold out much longer hoping for another big dip. The sweet spot feels like it's roughly now, especially on the 100-280Ah cells.

Yeah the timing's probably right tbh. One thing worth factoring in beyond the headline price — with LiFePO4 you can actually use nearly all of that 200Ah, whereas your AGMs are realistically only giving you 100Ah of usable capacity before you start hammering them. So a like-for-like swap isn't really like-for-like at all.

@Gazza82 which supplier did you end up going with? There's a few floating around at the moment with varying quality on the BMS side of things — that's where I'd be doing my homework before pulling the trigger. Some of the budget cells are fine, others less so.

@LazyWarden for a garden office setup you'll want to think about low-temperature charging cutoff too if it's unheated — caught a few people out over winter with that one.

Just to add something nobody's mentioned yet — if you're running a split charge relay setup in the van, @Paddy78, you'll want to sort that out before you switch. Most standard VSRs are calibrated for AGM charge profiles and will either undercharge LiFePO4 or keep the alternator loaded longer than it should be. Worth upgrading to a proper DC-DC charger like a Victron Orion or similar. Adds a bit to the upfront cost but protects both your battery and the alternator. I've seen a few people make the switch, save money on the cells, then have alternator grief six months later because they didn't account for it. Small thing but worth budgeting for from the start rather than discovering it the hard way! 🔧

Great timing on this thread — I switched out a similar AGM bank about 18 months ago and haven't looked back. One thing worth flagging that I don't think's been touched on yet: check your existing charger/inverter compatibility before you commit. A lot of the older units have charge profiles that don't play nicely with LiFePO4 — you really want a dedicated lithium profile otherwise you're potentially undercharging or, worse, stressing the cells. Took me an embarrassing amount of time to realise my old Sterling unit needed a firmware update before it behaved properly. Might be worth budgeting a small amount on top for a decent DC-DC charger if your alternator setup needs it too — @SandySparky's point about split charge relays is spot on in that regard.

Fogstar Drift cells have been sitting in my tiny house for two years now and the only thing that's "struggled" is my wallet accepting I should've done it sooner — pulled the trigger when prices dipped below £200 for a 100Ah and never looked back @Paddy78.