Anyone else using a Raspberry Pi to log their battery data locally instead of relying on cloud apps?

Been doing exactly this on the narrowboat for about eight months now, and honestly it's transformed how I understand the system.

Running a Pi 4 with Venus OS flashed onto it — essentially turns it into a DIY Cerbo GX at a fraction of the cost. It pulls data directly from my Victron MPPT and BMV-712 over VE.Direct cables, then I've got InfluxDB storing everything locally with Grafana sat on top for the dashboards.

The moment it clicked for me was watching a full 24-hour charge/discharge cycle visualised properly for the first time. Spotted that my Fogstar Drift 200Ah was hitting absorption earlier than expected on overcast days — something I'd never have caught just glancing at the app.

A few things I'd flag for anyone considering it:

• VE.Direct USB cables are the painless route in
• Pi 3B+ works fine if you've got one gathering dust
• Set your InfluxDB retention policy early or your SD card will fill up surprisingly fast

The real win over Victron's own cloud portal is the data stays yours, on your boat, even when you're miles from any signal — which on the cut is basically always.

Curious whether anyone's gone further and added current clamps for loads that sit outside the Victron ecosystem? I've got a diesel heater and an inverter-driven induction hob that are invisible to the BMS at the moment, and it's a gap that bothers me.

@RiverSoul Venus OS on a Pi is the obvious choice if you're already in the Victron ecosystem, but worth flagging — if you've got kit that doesn't talk to Victron natively, you might hit walls.

Been running a Pi 4 myself logging via Node-RED → InfluxDB → Grafana. Pulls data from my Fogstar Drift cells over RS485 and gives me proper historical trends rather than just "what's happening now."

The cloud-free angle is underrated. VRM portal is decent but I've had it go offline at awkward moments when I needed data most.

Main gotcha: SD card wear. Running the database off a USB SSD rather than the card itself made a noticeable difference to reliability. Lost one card to write exhaustion before I wised up.

What BMS are you running for the data source?

Been doing something similar in the van - Pi Zero 2 W running a lightweight stack (InfluxDB + Grafana) pulling data from my Fogstar Drift via a cheap RS485 dongle. No Venus OS but works a treat for local logging.

The satisfying bit is having Grafana dashboards visible on a small touchscreen mounted near the leisure area - can glance at state of charge without opening any app.

One thing I'd add that nobody's mentioned: set your Pi to read-only filesystem when you're not actively tweaking it. Kills the SD card corruption issue dead, which is the classic Pi failure point when you've got it running 24/7 in a vehicle bouncing down country lanes.

@RiverSoul eight months of data sounds brilliant - bet you've spotted some patterns in how your bank actually behaves vs what the BMS claims.

@RiverSoul done similar on the narrowboat but went a different route — straight RS485 to USB adaptor into a Pi 3B pulling data from the Victron kit via Modbus. No Venus OS, just a Python script I bodged together from bits online.

Grafana dashboards are decent once you've got them set up but getting InfluxDB retention policies right is a faff nobody warns you about.

Main question I can't get answered anywhere: what happens when the Pi loses power mid-write? Had a couple of corrupted databases already and it's getting tedious. Running it off a small 18650 cell with a UPS hat at the moment but feels like overkill.

Anyone found a more resilient storage solution? Heard SQLite is less prone to corruption than InfluxDB on sudden shutdowns but not tried it yet.

Good timing on this thread — been meaning to set something similar up on the narrowboat.

Couple of questions before I commit to anything:

1. How are you handling SD card wear? I've read that running InfluxDB writes constantly will kill a card in months. Are people using USB SSDs instead, or writing to a NAS over the network?

2. @BurnBen — with your InfluxDB/Grafana stack, what retention policy are you running? Keeping every data point forever seems overkill but I don't want to lose trend data for seasonal comparison.

3. Anyone running this on a Pi Zero 2 W on battery alone? Curious what the parasitic draw looks like — even 1-2W matters when I'm on a mooring with no hookup.

Currently using Victron's own VRM portal but the idea of fully local logging appeals given patchy mobile signal in some of the cuts.

Great thread! @ExFirefighter what questions did you have? Happy to help where I can.

I'll add something nobody's mentioned yet — worth thinking about your SD card situation early on. Running databases like InfluxDB writes constantly to disk, and standard SD cards can fail surprisingly quickly under that workload. I killed two cards in about three months before switching to booting from a small SSD via USB. Night and day in terms of reliability.

Also consider setting up automated backups of your Grafana dashboards and InfluxDB data to a USB drive or NAS. Losing months of battery trend data when a card dies is genuinely gutting, especially if you're trying to spot long-term degradation patterns in your bank.

The monitoring itself is brilliant once it's stable — being able to correlate solar input against weather and usage patterns has completely changed how I manage things.