Anyone else running Victron MPPT with a Fogstar Drift LiFePO4 — what charge profile are you using?

Just swapped out my old AGM bank for a 200Ah Fogstar Drift and trying to nail down the Victron SmartSolar settings properly. Fogstar's docs say 14.2V absorption, 13.5V float, but I've seen people running 14.4V without issues.

Currently on a 40A MPPT (100/40) feeding a modest 400W array on my shed roof. Mostly running lights, a 12V fridge and some USB stuff — nothing massive. BMS cuts in at 14.6V so there's headroom, but don't want to be pushing it daily.

Anyone dialled this in nicely via VRM or the Bluetooth app? Wondering if absorption time matters much with LiFePO4 or if I should just keep it short — say 1 hour max?

@RetiredEngineer86 — had almost exactly this journey when I wired up my shepherd's hut build last spring.

I'm running a 100/30 SmartSolar with a 200Ah Drift and settled on:

• Absorption: 14.2V
• Float: 13.5V
• Absorption time: adaptive, capped at 1hr

The bit Fogstar's docs don't shout about — drop your tail current to around 4% in VictronConnect. That's what actually tells the MPPT the battery is genuinely full, rather than sitting at absorption voltage forever. Made a noticeable difference to my cycle counts.

Also worth enabling BatteryLife if you're not regularly hitting 100%, which in a hut that sits empty mid-week is basically always.

Six months in, the Drift's behaving beautifully. No complaints.

Great topic @RetiredEngineer86 — I've been running a 100Ah Drift with a SmartSolar 100/30 for about eight months now and it's been rock solid.

One thing worth adding to whatever @GaryParker97 has shared: I'd strongly recommend enabling the BatteryLife algorithm off and setting a fixed absorption time rather than relying on adaptive. The Drift's internal BMS is doing the heavy lifting, so you don't need Victron second-guessing the tail current too aggressively.

I'm using 14.2V absorption with a fixed 1-hour timer, 13.5V float, and I've disabled equalization entirely — obviously never run equalisation on LiFePO4!

Also worth connecting via Bluetooth and checking the VictronConnect app occasionally to confirm you're genuinely hitting absorption properly on cloudy days. Mine occasionally skips it in winter with limited solar input.

What's your panel wattage? That might affect the advice slightly.

Great thread — this is almost exactly my setup on the boat. I'm running a 200Ah Drift paired with a SmartSolar 100/20 and after a fair bit of experimenting I've settled on 14.2V absorption, 13.5V float as Fogstar recommend, but I've dropped my absorption time right down to about 20 minutes rather than letting it run the full default. The Drift charges so efficiently that extended absorption really isn't needed once you're past roughly 80% SOC.

One thing worth flagging @RetiredEngineer86 — make sure you've disabled the equalisation function entirely if it's showing in your profile. Caught me out initially. Also worth enabling the battery voltage sense in VictronConnect if you're running any meaningful cable run, keeps things accurate at the battery terminals rather than the controller. @GaryParker97 probably found the same thing on his hut build.

Fogstar's own numbers work fine in my motorhome — just make sure you've got the BMS protection voltage set lower than your Victron's low voltage disconnect or you'll spend a confused afternoon wondering why everything's shutting off randomly like I did.

Been running this exact combo on the narrowboat for two winters now. The Fogstar spec sheet is sound — I stuck rigidly to 14.2V/13.5V and honestly the battery hasn't complained once.

My only addition: set your absorption time shorter than you think. Victron's adaptive algorithm is clever but left to its own devices on a

Great thread! One thing I'd add that hasn't been mentioned yet — make sure you've disabled the equalization setting if it's showing in your Victron app. Some profiles have it tucked away and it'll absolutely hammer a LiFePO4 if it kicks in unexpectedly. Also worth setting your absorption time to a fixed 2 hours maximum rather than letting the SmartSolar's adaptive algorithm run longer than needed — LiFePO4 really doesn't want prolonged high-voltage absorption like an AGM does. The Fogstar voltages @RetiredEngineer86 mentioned are spot on from my experience. I'd also pop a low temperature cutoff in if your installation is somewhere that gets properly cold — the Drift's BMS will protect you, but it's nicer to stop charging at the controller level before the BMS has to intervene. 👍

Good thread, this. One thing worth adding — if you're using VictronConnect to set this up, make sure you select the "Lithium" preset first as your starting point rather than trying to adapt a lead-acid profile. It handles the absorption time more sensibly for LiFePO4 out of the box.

Also worth enabling the tail current setting (around 2-4% of battery capacity) to end absorption early once charge tapers off — stops it sitting at absorption voltage longer than necessary. Pair that with @RetiredEngineer86's Fogstar numbers and you should be in good shape. 👍