Anyone else gone down the Fogstar Drift rabbit hole for van builds?

Just swapped out my tired old AGM bank for a pair of Fogstar Drift 100Ah LiFePO4 cells and honestly I'm a bit annoyed I waited this long — the weight saving alone has me feeling like I've done a proper diet.

Running them through a Victron SmartShunt and the BMS comms are behaving themselves nicely over Bluetooth, though I did have a brief moment of panic during the first top-balance that I'm choosing not to talk about.

Curious whether anyone's gone bigger — the 200Ah Drift units specifically — and whether they're playing nicely in a twin-battery setup without the cells drifting apart over winter when the van's sat unused for weeks at a stretch?

HarbourKate | 847 posts

@MarineClare oh tell me about it! I did exactly the same swap on my Transit about eight months ago and the weight difference genuinely surprised me — I knew the numbers on paper but actually lifting them out versus the old AGMs was a proper "oh wow" moment 😄

One thing worth mentioning that I don't see discussed enough: give them a few proper charge/discharge cycles before you judge capacity. Mine seemed slightly underwhelming the first week then sort of "woke up" after maybe five or six cycles and have been brilliant since.

Also if you're running a split charge relay from the alternator, worth checking it's lithium-compatible or you might want a DC-DC charger in there — learned that one the slightly embarrassing way! What size inverter are you running with them?

@MarineClare two Drift 100Ahs freed up so much weight in my van I accidentally became a better driver — the handling improved or my ego did, genuinely can't tell which.

LutonDream | 312 posts

@MarineClae and @DevonNomad — the weight thing is real isn't it! I've got a pair of Drift 200Ahs in my Luton box van build and the BMS behaviour has genuinely impressed me. Had a couple of very cold nights up in the Peaks last month, temps dropped to around -2°C, and the low-temp cutoff kicked in exactly as it should — no drama, no damaged cells. Charged fine once things warmed up the next morning.

One thing worth flagging for anyone considering the swap — make sure your alternator charging setup has a proper DC-DC charger in the loop. The Drifts will happily take whatever you throw at them but your alternator won't thank you for it without one. Renogy and Victron both do decent units at sensible prices.

Not a van lad myself but running a pair of Drift 100Ahs in the shepherds hut and they've been absolutely solid.

The BMS has never done anything dramatic which is honestly all you want from a battery — just quietly get on with it.

One thing worth mentioning for anyone pairing them with a Victron MPPT: set your absorption voltage correctly from the start, don't just leave it on the AGM preset like I nearly did 🤦 Took me about 20 minutes of head-scratching before I realised what I'd done.

@LutonDream curious what you're running yours with — any Victron kit or something else?

Drift 100Ahs in my cabin and on the boat — same cells, two very different environments. The boat ones have seen some pretty grim conditions (condensation, vibration, the odd aggressive channel crossing) and they're still performing bang on spec after 18 months.

One thing I'd flag for van folk that maybe matters less in a static setup — make sure your battery boxes have decent ventilation even though they're LiFePO4. Not a gassing issue obviously, but thermal management in a van that sits in August sun can be brutal. Mounted mine away from direct hull heat on the boat for exactly that reason.

@GazAllen curious what BMS you're running with yours — I went with a Victron SmartShunt alongside and the two play together nicely but I know some people have had communication quirks.