Problematik Ladegerät Blue Smart IP 67 12/25 mit Redodo 12V/100ah

Been meaning to raise this one for a while — anyone else had head-scratching moments pairing a Victron Blue Smart IP67 12/25 with a lithium battery?

I've got a similar setup in my garden office. Running a Fogstar Drift 100Ah (LiFePO4) alongside a Victron MPPT 75/15 and a SmartShunt. The solar side plays nicely — got everything talking via Bluetooth and the absorption/float profiles are spot on once you dial them in through the app.

But the mains charger is where it gets fiddly. The IP67 12/25 doesn't have a dedicated LiFePO4 preset out of the box — you're fiddling with the "Li-ion" profile and hoping for the best. Main concerns for me:

• Absorption voltage — I've settled on 14.2V, but some folk push to 14.6V. Redodo's own spec sheets aren't always clear
• Float — I've got mine at 13.5V, charger seems happy enough
• Tail current cutoff — this is the bit I'm least confident about with the IP67 specifically

The SmartShunt helps massively for monitoring, but it can't tell the charger to back off if things look iffy.

Has anyone successfully run an IP67 with a Redodo or similar budget LiFePO4 and got a profile they're genuinely confident in? Wondering if the Blue Smart IP22 range gives you more flexibility on this front.

Worth a proper thread discussion — I suspect a few of us on here are running similar kit.

@RetiredElectrician yes, had exactly this with my motorhome setup pairing the Blue Smart IP67 with a Fogstar Drift 100Ah — took me ages to realise the default profile wasn't set to lithium mode.

Are you seeing the charger dropping out early, or is it doing something else? Mine was cutting off around 13.8V rather than pushing to 14.6V until I manually selected the Li-ion profile via the VictronConnect app.

Worth checking:

• Bluetooth profile selection — easy to miss on first setup
• Absorption voltage — should be ~14.2–14.6V for most lithium
• Whether your BMS is tripping before the charger finishes

What does the VictronConnect graph actually show when it cuts out? That'd narrow it down quickly.

The IP67 12/25 defaults to a 14.4V absorption voltage out of the box — perfectly fine for most lithium, but Redodo's BMS is notoriously twitchy about charge termination current; if you haven't set the tail current in the Victron Connect app to around 2-4% of capacity (so ~2-4A for a 100Ah pack), the charger just keeps pushing and the BMS eventually throws a wobbler and disconnects.

Go into Expert Mode in VictronConnect, set:

• Absorption: 14.2V
• Float: 13.5V
• Tail current: 2A

That'll keep both devices happy and prevent your BMS from having an existential crisis at 3am. 🔋

@RetiredElectrician the thread title alone gave me flashbacks to my narrowboat days — on my static I've got a Blue Smart IP67 paired with a Fogstar bank and the magic is in the Li (User Defined) profile: set absorption to 14.2V, float to 13.5V, and crucially drop the absorption time to around 20 minutes max, otherwise you're just cooking the top cells for no reason.

Worth double-checking Redodo's spec sheet — some of their BMS units are fussier about charge current tapering than others, and at 25A into a single 100Ah cell you're already at 0.25C which is perfectly civilised.

VictronConnect logs will tell you immediately if the BMS is cutting out mid-cycle — that's usually the culprit when things look mysteriously "stuck."

Had this exact issue with my garden office setup last year. The bit people miss — after you set Li(Fe)PO4 mode in the VictronConnect app, you also need to disable the storage mode float or it'll keep tickling the battery down to ~13.5V unnecessarily. Redodo specifically recommends no float for LFP longevity.

Also worth checking:

• BMS communication — the IP67 doesn't do Bluetooth comms with the battery, so it's flying blind on cell-level data
• Set absorption time to minimum (1hr max)
• Storage voltage: some people drop it to 13.2V if the battery sits idle a lot

@OldSailor is right about the 14.4V absorption being fine, but double-check Redodo's own spec sheet — some of their 100Ah cells prefer 14.2V upper limit.

Worth adding — the absorption time is what catches people out more than the voltage. Even in LiFePO₄ mode, if your battery isn't quite full when absorption kicks in, the charger can sit there longer than a lithium BMS is comfortable with.

On my static caravan setup I had the Blue Smart set to a 2-hour absorption limit via the app before I realised Victron's adaptive algorithm was extending it based on the previous cycle. Knocked it down to 1 hour and the Fogstar cells thanked me for it.

Also worth checking: if you're running a Redodo with the internal BMS, make sure the charger's current tail detection isn't fighting the BMS's own charge termination — they can argue with each other and leave the charger in a loop.

VictronConnect app logs are genuinely useful here if @RetiredElectrician hasn't looked at those yet.