Charging Humsienk with Victron MPPT Question

Been running a Victron SmartSolar 100/30 for a couple of years now and generally very happy with it, but I've recently added a Humsienk LiFePO4 battery to the setup and I'm not 100% sure I've got the charge profile dialled in correctly.

The battery specs sheet says:

• Charge voltage: 14.6V
• Float: 13.6V
• Max charge current: 30A

I've set the Victron to the LiFePO4 preset in the VictronConnect app, which gives me 14.2V absorption and 13.5V float. Should I be manually overriding these to match what Humsienk specify, or is the Victron preset generally considered "safe enough"?

Also — and this might be a daft question — the Humsienk has its own BMS obviously, so in theory it'll protect itself if something goes wrong. Does that mean the charge settings matter less than I think, or is it still worth being precise? I'd rather not rely on the BMS as a safety net if I can avoid it.

Anyone running a similar lesser-known LiFePO4 brand with a Victron MPPT? Curious whether people tend to trust the manufacturer's specs sheet or stick with Victron's presets. The two don't seem wildly different but I want to make sure I'm not leaving charge capacity on the table or, worse, stressing the cells.

Got a Humsienk on the narrowboat myself — decent budget cell for the price.

Main thing with the SmartSolar and any LiFePO4 is making sure you've got a dedicated Li profile set rather than just bumping the absorption voltage up on a lead-acid preset. The 100/30 lets you create a user-defined profile in the VictronConnect app.

Key settings I'd start with:

• Absorption: 14.2–14.4V
• Float: 13.5V (some people drop this lower or disable float entirely)
• Absorption time: keep it short, 1–2 hrs max

Also worth checking whether your Humsienk BMS has a charge disconnect threshold — if it cuts out at high voltage the MPPT can throw errors. Not a fault, just how it behaves.

What's the rest of your OP saying? Looks like it got cut off mid-sentence.

Great question — I went through exactly this when I switched my narrowboat over from AGM to LiFePO4 last spring.

The bit people often miss with the SmartSolar is the tail current setting. On lithium, you want to set that pretty low — around 1-2% of battery capacity — otherwise the MPPT thinks the battery is full before it actually is, and you end up chronically undercharged without realising it.

Also worth enabling the battery voltage sense if your SmartSolar has separate sense terminals (the 100/30 does). Compensates for any cable voltage drop and means your charge profile is accurate at the battery terminals rather than the controller.

@BoatEwan is right about the profile settings, but the tail current thing catches a lot of people out and it's buried in the VictronConnect advanced settings rather than the main screen.

Just set absorption to 14.2V and float to 13.5V on mine and the Fogstar/Victron combo has been rock solid — the Humsienk cells are probably fine with similar numbers but double-check your BMS cutoff voltage and make sure the MPPT charge profile never exceeds it or your BMS will just boot the charger off like an unwanted guest at closing time.

Something worth flagging that I don't think anyone's mentioned yet — with the Humsienk cells specifically, check whether your pack has an integrated BMS with high-voltage cutoff. Some of the budget Chinese LiFePO4 packs do, some don't, and it matters for how aggressive you set your Victron profile.

On my van build I run 14.2V absorption, 13.4V float (slightly lower than @ThistleVicky's 13.5V — either is fine), but critically I also set the absorption time to around 20-30 minutes max rather than letting the Victron calculate it dynamically. LiFePO4 doesn't need long absorption periods and extended time up there generates unnecessary heat in the cells.

Also make sure battery voltage sensing is enabled in VictronConnect — if you're running any meaningful cable length, voltage drop will skew the readings and you'll never quite reach proper charge termination.