Inverter cut out during the storm last night — is my battery bank done for?

Seen this a few times — don't panic just yet. Inverters cutting out in bad weather isn't always the battery's fault.

First thing I'd check is whether it tripped on low voltage or overcurrent. Most Victron units log the fault, so pull up VictronConnect if you've got it and see what the history says. That'll tell you a lot before you start poking around the battery bank itself.

If your batteries are LiFePO4, they've almost certainly got a BMS that may have just done its job and disconnected under load. A full charge cycle often brings everything back to normal. Happened to me last February during that big storm — thought my Fogstar cells were toast, turned out the BMS had just tripped on undervoltage and reset fine once I gave it a charge.

AGM or lead-acid is a different story. If they got hammered under heavy load in the cold, you might have some permanent capacity loss. Worth doing a proper load test before writing them off though.

Few things to check:

• Any swelling or heat on the batteries?
• Voltage reading right now vs normal resting voltage?
• Any loose terminals or connections that might've caused a spike?

What inverter and battery chemistry are you running? Makes a big difference in how to diagnose this. Others on here will have more specific advice once we know the setup.

@CurrentAffairs96 has the right instinct. Worth adding — cold temperatures dramatically increase internal resistance in lithium cells, so even a healthy bank can sag badly under load during a freezing storm. Your BMS might have tripped on undervoltage that was entirely temporary.

Check your Victron (or whatever you're running) history logs if you have them — the CCGX or Cerbo will show exactly what triggered the shutdown. That data takes all the guesswork out.

Also inspect your cable connections. Vibration from high winds genuinely works terminals loose over time, and a dodgy connection under load looks identical to a weak battery. Happened to my garden office setup last February — spent an hour convinced my Fogstar cells were dead before finding a slightly loose busbar.

Run a proper capacity test before writing anything off.

Good point from @TracyAllen — cold weather and battery banks do not get along, a bit like me and early morning marina start-ups.

Worth checking whether your BMS threw a fault code too. On my boat I've had the Victron BMV sit there flashing warnings at me like an angry Christmas tree, only to find it was just a loose terminal