How to store lithium superpack

Been running a similar setup at my cabin for the past couple of seasons — Victron SmartShunt, MPPT 100/50, and a 200Ah LiFePO4 pack (Fogstar Drift in my case rather than the Superpack, but the chemistry is the same).

The storage question is something I've been thinking about ahead of winter. From what I've gathered and experienced:

Target SoC for storage
Most manufacturers recommend parking LiFePO4 at around 50% SoC for any extended period rather than leaving it fully charged. Leaving it at 100% for months causes minor but cumulative stress to the cells. The Victron Superpack doesn't have an external balancer input, so you're relying entirely on the internal BMS to manage this.

Temperature matters more than people realise
LiFePO4 doesn't like being charged below 0°C, but storing at low temps is generally fine as long as you're not asking the BMS to do anything. My cabin drops well below freezing from November onwards, so I disconnect and bring the battery indoors over winter. Around 10–15°C seems to be the sweet spot for storage.

Self-discharge
These cells are remarkably stable in storage — you're losing maybe 1–3% per month in ideal conditions. I'd still recommend checking voltage every 6–8 weeks if it's sitting unused, just to confirm the BMS hasn't triggered an undervoltage lockout.

Curious whether anyone has left a Superpack specifically connected to a dormant MPPT over winter with no loads — does the Victron ecosystem handle the float/storage mode cleanly enough to trust it unattended? That's the bit I haven't fully committed to yet.

Hey @WezWhite72 — sounds like a solid setup! For storage, LiFePO4 is pretty forgiving compared to other lithium chemistries, but I'd still recommend parking it at around 50% SoC rather than full. Leaving it brim-full for months puts unnecessary stress on the cells. The Victron ecosystem makes this dead easy — just set a storage charge voltage of around 26.8–27V on your MPPT and let it settle there before you disconnect everything.

Also worth keeping it somewhere with reasonably stable temperatures — a frost-free garage or insulated space is ideal. Below freezing won't damage LiFePO4 in storage the way it would during charging, but it's still better avoided long-term.

Disconnect your SmartShunt's negative lead too, otherwise the quiescent draw will slowly nibble away at it over winter. Small thing but worth doing!

@DaiWright makes fair points but one thing worth adding — if you're storing it in a cabin over winter, watch the temperature. LiFePO4 doesn't like being charged in sub-zero temps even if discharge is fine. Had my garden office pack sat at around 50% through last winter, BMS handled it no bother but I made sure not to let the MPPT push charge into it on frosty mornings.

Stuck a cheap wireless thermometer inside the battery enclosure — gives me peace of mind checking from the house app. Renogy do decent ones, nowt fancy needed.

Also worth disabling any scheduled equilisation if your charger has that — not relevant for LiFePO4 and can cause grief.

Good shout from @NigeCampbell81 on the temperature angle — learned that one the hard way with my static van setup. What I'd add is: disconnect everything before you walk away for the season, not just the loads. Had a Victron SmartShunt quietly drawing a phantom load over three months and came back to a pack that had drifted well below that comfortable 50% storage charge. Nothing catastrophic with LiFePO4, but it wasn't ideal.

A small timed relay to kill the entire DC bus sorted it for me. Cheap insurance really. Also worth leaving a note on the unit with the date you stored it and the SOC — sounds daft, but future-you will be grateful come spring when you can't remember a thing about last October.

@HiluxConvert storage SoC is the one people always skip — park your Fogstar or Superpack at around 50% and it'll thank you come spring like a golden retriever who forgot you'd been away.