LifePo4 48v DIY pack (in small network cabinet housing)

Been toying with this idea for my motorhome build for a while now. Network cabinets are genuinely underrated for battery housing — decent steel construction, rack mount options, and you can pick up second-hand ones for peanuts on eBay.

My plan is a 16S LiFePO4 pack using 280Ah prismatic cells. Still sourcing cells — looking at Fogstar or going direct from a reputable AliExpress seller with capacity tested cells. Anyone gone down that route recently and got a supplier they'd trust?

For the BMS I'm leaning towards a Daly Smart BMS (150A version) — seems solid for the money and the Bluetooth monitoring is handy. Though I know some folks swear by the JK BMS for better balancing. Open to thoughts on that one.

Few things I'm still working through:

• Ventilation — even with LiFePO4 being relatively stable, still want some airflow in the cabinet
• Busbars — proper copper ones or nickel-plated?
• Cell compression — how much pressure are people putting on prismatic cells in a rigid enclosure?

The cabinet I've got in mind is a 6U wall-mount unit, which should fit the cells in two rows of 8 with room for the BMS and fusing. Tight but doable.

Running it with a Victron Multiplus-II and Cerbo GX so ideally want proper CAN bus comms between BMS and the Victron ecosystem — that's pushing me slightly toward the JK actually.

Anyone built something similar? Particularly interested if you've managed this in a vehicle environment rather than a static setup — vibration and temperature swings are

@SuffolkSolar Solid idea in principle, but mind the ventilation — those cabinets were designed to keep electronics cool, not to vent hydrogen or manage thermal runaway, so LiFePO4 is considerably safer than lead-acid but you'll still want a deliberate exhaust path if your BMS has a venting scenario.

Rack-mounting the cells vertically is fine for prismatic cells, but make sure your busbar work is properly torqued — loose connections in a mobile application will arc eventually and ruin your day spectacularly.

A Daly or JK BMS slides into 1U/2U rack space beautifully, and your Victron kit can live in the same cabinet if you keep the inverter outside (heat monster).

One genuine gotcha: cabinet steel is brilliant at conducting vibration straight into your cell terminals on a moving vehicle — rubber isolation mounts between rack and van floor, not optional.

Did exactly this for my cabin build — 6U wall-mount cabinet from a local IT recycler, cost me a tenner.

One thing nobody mentions: the door latches on cheap cabinets are rubbish. Vibration from road use will have them rattling open constantly. Worth swapping for something with a proper cam lock before you even think about putting cells in.

Also check your cabinet dimensions against your cell count before buying. Sounds obvious but 280Ah prismatic cells are chunkier than most spec sheets suggest once you account for compression plates and busbars. I lost a frustrating afternoon discovering my "perfect fit" was 12mm too narrow.

@SuffolkSolar what cells are you going with? If you're sourcing Fogstar or similar, get the exact dimensions off them directly — the listings aren't always accurate.

@SuffolkSolar great project — I went down a similar rabbit hole for my narrowboat build last year.

One thing worth thinking about with 48V packs in metal enclosures: busbar routing and inter-cell wiring clearances. Steel cabinets can create some awkward grounding paths if you're not deliberate about it, and with 48V you've got enough potential to cause mischief if a lug vibrates loose against the chassis.

I'd strongly suggest:

• Proper insulated busbar covers (Victron do nice ones, or generic DIN rail covers work)
• Painting or taping any internal edges near positive connections
• Earthing the cabinet chassis to your negative busbar intentionally rather than accidentally

Also worth checking whether your BMS comms (if running CAN or RS485 to a Victron Cerbo or similar) picks up noise from being inside an earthed steel box — mine did initially, needed a ferrite core to sort it.

@SuffolkSolar worth noting that 48V LiFePO4 in a metal cabinet creates some interesting busbar routing challenges — particularly keeping positive and negative runs short and symmetrical to avoid imbalanced cell loading. I did something similar in my LDV Convoy conversion using a 9U rack, and ended up fabricating copper busbars from 25mm² strip rather than relying on cable runs between cells.

Also worth considering: network cabinets often have knockouts or pre-punched cable entry points that aren't rated for the cable gland sizes you'll need for serious DC cabling. I replaced mine with proper IP-rated glands from Buccaneer — belt and braces approach but eliminates any moisture ingress risk, which matters enormously in a motorhome environment where condensation cycles are brutal.

What BMS are you planning? JK or Daly both have decent rack-mount form factors if you want to keep everything tidy inside the enclosure.