BSC IP67 12/17 Charger voltage very wrong, won't charge

Had something eerily similar with my Victron IP67 12/17 on the boat last spring — plugged it in after a winter lay-up and the thing was convinced my 100Ah LiFePO4 was sitting at about 4 volts when it was clearly 13.1V on the multimeter.

Turned out the sense wires had developed a dodgy connection at the ring terminal, so the charger was reading phantom voltage and sulking accordingly. Worth checking those first before you do anything drastic.

A few things worth trying in rough order:

• Check your connections — corroded terminals are basically a rite of passage on anything marine
• Force a manual profile reset via the VictronConnect app if yours supports it
• Try a different battery if you have one knocking about, just to rule out whether it's the charger or the battery BMS throwing a wobbly
• Firmware update — fixed a voltage sensing quirk on mine, Victron quietly pushed one out last year

Also worth noting: some LFP batteries with a BMS will actively confuse chargers by presenting weird resting voltages if the BMS has tripped. Fogstar Drift cells are brilliant but their BMS can occasionally throw a strop and appear "dead" to a charger.

Is yours reading low voltage or no voltage? Makes a difference in terms of where the fault likely sits.

Anyone else had their BSC charger lose the plot after a long period of inactivity? Feels like these units don't love sitting unused — bit like me, really.

@BoatMark classic case of the charger having a proper sulk after winter — mine did exactly the same on the narrowboat, turns out the Victron couldn't sense enough voltage to kick into bulk mode because the BMS had gone into deep sleep protection.

Whack a fully charged 12V lead-acid across the terminals for 30 seconds to wake the LiFePO4 back up, then let the IP67 have a go — works a treat.

@BoatMark mine did this exact thing with my cabin setup — Victron had a complete meltdown after a cold snap, convinced itself the world was ending 😂

Worth trying the manual equalisation/forced bulk trick — hold the mode button until it stops sulking and kicks into proper bulk charge. Sometimes these things just need a firm talking-to.

@BoatMark the Victron IP67 stores last-known voltage in memory and if the battery dropped below the low-voltage lockout threshold over winter (~2.something volts), it enters a protection mode that requires a "wake-up" charge — grab a basic lead-acid charger, tickle the LiFePO4 up past 10V for a few minutes, then reconnect the Victron and it'll snap back to its senses like it never had a wobble.

⚠️ Obviously confirm your BMS is happy before doing anything — don't go bypassing protections willy-nilly on a narrowboat unless you fancy a very dramatic spring launch.

Had this exact pantomime on my static caravan with a Fogstar 200Ah after a brutal January — five minutes with an old charger from the shed and the Victron was back being its smug, reliable self.

@RetiredChef is on the right track but there's a bit more to it than just memory retention. What people consistently overlook is the soft-start recovery sequence — the IP67 won't enter normal charge mode if it detects terminal voltage below roughly 5V on a 12V bank. It assumes dead cell or disconnected battery and throttles back to a trickle probe current (around 1A if I recall correctly).

The fix that worked on my static caravan setup: manually pre-charge the LiFePO4 to above 10V using a bench PSU or even a donor battery before connecting the Victron. Once it sees a sensible voltage on the terminals it'll snap out of its little strop and behave normally.

Worth checking your BMS hasn't tripped independently as well — two separate faults presenting simultaneously is more common than people think after a cold lay-up.