Upgrading to LiFePO4 using Victron Blue Smart & Orion-Tr Smart chargers - Feedback wanted

Recently went through exactly this kind of upgrade on my boat — swapped out a tired AGM bank for 200Ah of LiFePO4 (Fogstar Drift cells) and it's been a proper game-changer.

The bit that tripped me up initially was getting the Orion-Tr Smart and Blue Smart IP67 to play nicely together when the BMS cuts in. Victron's ecosystem is brilliant in theory, but you do need to spend time in VictronConnect making sure your charge profiles aren't fighting each other. I had the Orion-Tr briefly pushing voltage into a disconnected bank because the BMS had tripped — not ideal.

A few things worth considering if you're doing this on a 12V boat system:

• Absorption voltage — LiFePO4 wants 14.2–14.6V, not the 14.7V+ you'd use for AGM. Easy to get wrong if you're reusing old settings
• BMS comms — if your BMS supports it, the Victron VE.Bus/VE.Direct integration is worth setting up properly rather than relying on voltage alone
• Alternator protection — are you running engine charging too? That's a whole separate conversation around B2B chargers and protecting your alternator from sudden load drops

Would be interested to hear from others who've integrated the SmartSolar MPPT into a similar setup — I'm adding a 175W panel shortly and wondering whether anyone's had issues with the three charging sources (solar, shore, alternator B2B) all trying to do their thing simultaneously.

What BMS are you running? That tends to dictate how straightforward the whole thing is.

@DODQueen the bit that trips everyone up — and it nearly caught me on my narrowboat too — is the absorption phase timing.

Victron's default absorption profile assumes lead-acid behaviour, so it'll sit at 14.4V for an age trying to "top off" a battery that's already full. With LiFePO4 you want absorption kept very short or effectively eliminated — the cells don't need it and you're just generating heat for no reason.

On my Blue Smart I set absorption to roughly 5-10 minutes maximum, charge voltage at 14.2V, and float down at 13.5V (essentially a storage voltage).

The BMS will still disconnect if something goes sideways, but why stress the cells unnecessarily?

Worth double-checking your Fogstar's spec sheet — the Drift cells have slightly different upper voltage tolerances compared to the Fog Star Solid, and it matters more than people realise.

@DODQueen this is really timely — I'm mid-planning a LiFePO4 upgrade for my garden office setup right now, also looking at Fogstar cells.

Quick question that's been nagging me: when you moved to the Orion-Tr Smart for DC-DC charging from the vehicle/alternator side, did you need to do anything specific with the engine-running detection, or does it handle that automatically through the VE.Smart networking?

I've read conflicting things about whether you need a separate alternator sense wire or if the voltage threshold detection is reliable enough on its own. Worried about accidentally drawing from the starter battery if the detection fails.

Also — did you keep any of the original AGM wiring or did you have to upsize cables for the LiFePO4 bank? I'm trying to work out if my existing 16mm² runs will be adequate.

@DODQueen great thread. One thing I'd add that nobody's mentioned yet — when you're configuring the Orion-Tr Smart for LiFePO4, pay close attention to the input voltage lockout settings. On a narrowboat with a split charge setup, you really don't want the DC-DC charger attempting to pull from a partially discharged starter battery.

Set your input lockout around 12.8V minimum to protect the engine battery.

Also, @MelKing83 for a garden office you'll likely be on mains via the Blue Smart predominantly — make sure you select the LiFePO4 preset explicitly rather than trying to manually tweak a user-defined profile. Victron's preset is actually very well calibrated at 14.2V absorption, 13.5V float, which suits Fogstar Drift cells nicely without stressing them.

The BMS will protect you ultimately, but it's far better practice not to rely on it constantly tripping.

Great thread @DODQueen, and nice to see Fogstar Drift cells getting a mention — I've got a similar setup in my static caravan and they've been brilliant.

One thing worth flagging that nobody's touched on yet: make sure your Blue Smart charger profile has absorption time set to minimum (or effectively zero if your firmware allows it). LiFePO4 doesn't need the prolonged absorption that AGMs do — you're basically just topping the last few percent up at constant voltage briefly then stopping. Leaving it at a long absorption setting won't damage the cells necessarily, but you're keeping the BMS working overtime for no real benefit.

Also @MelKing83 for a garden office setup, definitely worth checking whether your Orion-Tr input voltage range suits your alternator or solar source — easy to overlook during planning! 🙂

@MelKing83 snap — garden office is exactly what I used Fogstar + Victron for. One thing worth flagging: the Blue Smart charger's LiFePO4 preset is decent out the box but I'd still double-check the absorption voltage matches your BMS spec. Mine was slightly off and the BMS kept kicking it out early before cells were properly topped up.

Also if you're running the Orion-Tr Smart for DC-DC charging from a vehicle or secondary source — don't forget to enable the engine detection feature or you'll hammer your starter battery without realising.

Small things but they'll save you a headache. Took me two weekends to figure out what was going on 😅