What connections are these for the 2025 Eco-worthy 280Ah 48V battery??

Just picked up one of these myself for the boat and had the same head-scratching moment when it arrived. The two smaller terminals on the front panel are your RS485 communication ports — used for daisy-chaining multiple units together or connecting to a compatible BMS monitor/inverter comms. A lot of people miss that these aren't for power.

The larger brass terminals are obviously your main positive and negative, but worth noting the torque spec in the manual — I've seen people overtighten and crack the terminal housing on these budget cells.

One thing I'd flag: the communication protocol on the 2025 revision apparently changed slightly from the 2024 model. If you're running a Victron system and trying to get proper comms working, you may need to faff about with the DVCC settings and make sure you've got the right cable pinout. There's a thread on here somewhere about it but I can't find it right now.

Has anyone successfully got these talking to a Cerbo GX without issues? I'm still wrestling with mine — getting SOC readings but battery temps aren't coming through properly.

Would be good to hear from others running these in a 48V bank. Are you using them in parallel or series configurations? I'm running two in parallel on the boat and wondering whether the BMS balancing between units is handling it properly or whether I need an external balancer.

@OddJobBob60 RS485 — basically the battery's way of having a proper chat with your inverter/BMS monitor. Think of it as the battery's mouth. The big chunky terminals are obviously the muscle (power in/out), but without RS485 talking to something like a Victron Cerbo GX, you're essentially flying blind —

@OddJobBob60 those RS485 ports also play nicely with Victron kit via a cheap RS485-to-USB adaptor — lets you pull proper SOC data into VictronConnect rather than just guessing how smug your battery is feeling.

Great thread, this caught me out too when mine arrived last month! Just to add to what @MarineGeoff mentioned — if you're going the Victron route, make sure you grab the right cable pinout for your specific unit because I found the wiring diagram in the Eco-Worthy manual was a bit vague. Worth double-checking against the Victron Venus OS documentation before you wire anything up.

Also worth noting: the RS485 ports are typically daisy-chainable, so if you ever expand your bank with a second battery down the line, you can link them together in series communication rather than needing separate adaptors for each unit. Handy for future-proofing on a boat where space is always at a premium! 🚢

Really useful thread this. I'll add a practical note from when I wired up my static caravan setup last year — make sure you label which RS485 port is which before you do anything else. I made the rookie mistake of assuming they were interchangeable and spent a frustrating afternoon wondering why my monitoring software wasn't reading properly.

One port is typically for daisy-chaining additional batteries, the other for your external comms device. The Eco-Worthy documentation on this is... let's say generous in its vagueness, so worth double-checking against the actual port labelling on the unit itself rather than trusting the manual page numbering.

@MarineGeoff's point about the RS485-to-USB adaptor is spot on — grabbed a cheap one off Amazon and it worked first time with my Victron setup.