Lynx bms disconnects on low cell voltage but battery has 52V

Bit of a head-scratcher this one and wondering if anyone else has hit the same wall.

Setting up a 16S LiFePO4 pack for my garden office — Victron Lynx Smart BMS, Multiplus-II, Cerbo GX. Got about 52V across the battery terminals with a multimeter, cells all reading reasonably balanced in the VictronConnect app. But the Lynx keeps tripping on low cell voltage and disconnecting the load output.

The weird part is it's not actually low — pack voltage looks healthy enough. My suspicion is one or two cells are sagging under any load draw, even though resting voltage looks fine. Essentially the BMS is doing its job, but it's catching me off guard during what should be a straightforward commissioning phase.

A few things I'm considering:

• Cell-level logging — going to pull individual cell data from VictronConnect and watch what happens the moment I apply load
• Capacity check — Fogstar cells, relatively new, but wondering if a couple came slightly undercharged from storage
• BMS voltage threshold — default settings might be quite aggressive, worth checking what the low-cell cutoff is actually set to

Has anyone tuned the Lynx BMS cell voltage thresholds for a 16S setup? I'm a bit reluctant to loosen the protection settings without understanding the root cause first.

Also — did anyone find the AC disconnect phase of commissioning caused any odd BMS behaviour? Mine's running DC-coupled only at the moment which might be a factor.

Would love to know if others have seen this.

@ExJoiner9 classic cell imbalance issue. 52V pack average looks fine but if one rogue cell is sitting low the BMS will still trip on that individual cell voltage, not the pack total.

With 16S you've got plenty of room for one weak cell to drag things down while the rest sit healthy. Worth checking:

• Cell-level voltages via the Lynx Smart BMS app — it'll show individual cell readings
• Whether that low cell is consistently the same one (weak cell) or rotating (balancing issue)

If it's always the same cell, top balance the whole pack before giving up. If your Cerbo is connected, VRM portal sometimes catches the disconnect event with timestamps which helps narrow down which cell triggered it.

Had similar grief with a 16S Fogstar pack in my tiny house build — turned out one cell was just significantly under-capacity compared to the rest.

@Thommo already covered the obvious bit so I won't rehash it.

Worth checking whether your cells were properly top-balanced before assembly. Most people bottom-balance or don't bother at all and then wonder why this happens. A 16S pack with even one cell that's drifted 50-60mV low will trigger the Lynx well before pack voltage looks alarming.

On my own 280Ah EVE build I had exactly this — 52.8V pack, one cell sitting at 2.89V while the rest were comfortably above 3.2V. BMS cut out, looked like a fault, was just a lazy cell needing a proper balance cycle.

Use the Victron VRM or a decent cell-level monitor (I use a cheap but effective Bluetooth balancer) to actually see individual cell voltages. Don't guess. The Lynx logs should also show you exactly which cell threshold triggered the disconnect.

@ExJoiner9 classic symptom of buying cells that were "pre-balanced" by someone who clearly doesn't own a multimeter — what voltage did your lowest cell actually read when the BMS tripped?

Connect directly to individual cell terminals and log it; JK BMS app or even a decent DMM will show you the offender immediately. If one cell is dragging below ~2.8V while the rest are sat comfortably, you've got a dud or a loose busbar connection creating a false low reading.

Worth torquing every busbar connection before condemning the cell — seen a dodgy contact on a 280Ah EVE cell mimic exactly this on my cabin build. Victron's VictronConnect will show the BMS trip reason in the alarm history too, which narrows it down sharpish.

Really common stumbling block this one, and you're clearly asking the right questions — that's half the battle right there.

@SOC_Nerd makes a solid point about top-balancing. When I first wired up my van conversion I had almost exactly this scenario — pack voltage looked healthy but one cell was quietly dragging everything down.

One thing nobody's mentioned yet: once you've sorted the balance, check your Lynx BMS cell voltage thresholds in VictronConnect. The default low-cell cutoff can sometimes be set more aggressively than needed for LiFePO4. Worth cross-referencing against your cell datasheet and adjusting carefully.

Also log the individual cell voltages through the Cerbo GX — the historical data will tell you which cell is misbehaving and whether it's a capacity issue or purely balance drift.

Stick with it — these systems are brilliant once they're dialled in properly.