Correct lithium communication protocol for Must LP16-48100 (LP1600 series) batteries BMS and Growatt SPF 3000TL LVM-ES inverters

Been down this rabbit hole with a similar setup a while back so might be able to help, though not with that exact Must battery.

From what I recall, the Growatt SPF LVM-ES series is a bit fussy about lithium comms — it wants to talk to the BMS but the protocol options in the menu aren't always obvious. On mine I ended up trying "LiB" mode first (option 5 on the battery type setting) before eventually landing on RS485 with Pylontech protocol as that seemed to be the closest match for the BMS I was running.

The LP16-48100 is a 48V 100Ah unit yeah? Does it have an RS485 port on the BMS, or just CAN? That's usually where it falls over — Growatt's SPF range tends to prefer RS485 / Pylontech protocol, whereas some batteries only speak CAN.

Few things worth checking:

• Which firmware version is on your inverter?
• What cable pinout are you using on the comms port?
• Is the Must battery actually listed in the Growatt compatibility docs?

Honestly, I'd be a bit sceptical that full two-way comms works cleanly here without a protocol converter or some fiddling. Plenty of people just run these in standalone lithium mode with no comms and rely on the BMS to protect the cells directly — less elegant but it works.

Anyone else paired a Must LP series with a Growatt SPF? Curious whether there's a clean solution or whether it's just bodge territory.

@LuckySkipper fussier than my shepherd's hut neighbour complaining about generator noise at 7am, I imagine — worth checking whether the LP16 series wants PACE or Pylontech protocol selected on the Growatt side, because those two look identical until your BMS throws a wobbly at 3am and you wake up to a dead bank 🔋

Been through something similar getting comms sorted on my cabin setup. The Must LP16 series — at least the units I've handled — tends to want PACE BMS protocol rather than the more common RS485 Pylontech-style handshake that people assume will just work.

On the Growatt SPF LVM-ES side, there's a specific parameter (usually around setting 5 or the battery type selection) where you need to select user-defined lithium rather than a named brand preset. Get that wrong and the inverter either ignores the BMS entirely or throws a comms fault at you constantly.

Worth grabbing a USB-to-RS485 adapter and sniffing the actual traffic with something like PuTTY before assuming it's a cabling fault. Nine times out of ten it's a baud rate mismatch — 9600 vs 19200 catches people out repeatedly.

Right, so here's where it gets interesting with the Must LP16-48100 specifically.

The BMS communication protocol you want on the Growatt SPF 3000TL LVM-ES is RS485 with the Pylontech protocol selected — counterintuitive given it's a Must battery, but that's what worked when I was troubleshooting a similar Chinese-brand LiFePO4 pairing on my motorhome build.

On the Growatt side, navigate to:

• Setting 05 → set to LI
• Setting 36 → set to 2 (Pylontech protocol)

Baud rate should be 9600 on both ends.

One thing @MountainHermit might recognise — the RJ45 pinout on Must batteries isn't standard, so don't assume a straight-through cable works. Pin 4/5 for RS485 A/B is what I've seen documented, but verify against your specific unit's manual because firmware revisions do change things.

One thing worth adding from my shepherd's hut experience — even when you've got the protocol sorted and comms are talking properly, double-check your battery capacity settings in the Growatt parameters. Mine was defaulting to a conservative charge current limit that completely ignored what the BMS was actually reporting, so I was only ever pulling about 60% of what the LP16 pack could deliver.

Took me an embarrassingly long time to realise the inverter was just... ignoring the BMS suggestions on current.

Also worth logging the BMS output via a laptop before assuming comms are working correctly — I've seen setups where the handshake looks established but the data being passed is garbled. A USB-RS485 adapter and some basic terminal software will tell you pretty quickly if you're actually getting clean data through.