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April 11, 2026 11:51 pm
I have an EG4 12000XP off-grid inverter, it's currently equipped with the wifi dongle, but I want to remove that and switch to local monitoring. I'm wanting to try to do that myself versus buying the etherent dongle.
I'm trying to figure out how to get local monitoring via RS485, but I'm running into a port conflict and need help confirming the green terminal block pinout.
My comm board does NOT have the two upper RJ45 ports (CT1/CT2) that most guides reference for RS 485. My board only has BAT COM and Parallel.
My batteries are currently connected to the inverter via the BAT COM RJ45 port for closed-loop comms, so that port is occupied.
<div class="bbImageWrapper js-lbImage" title="1775951026041.png" data-src=" removed link " data-type="image" data-lb-sidebar-href="" data-lb-caption-extra-html="" data-single-image="1" data-fancybox="lb-post-1793427" data-caption="<h4>1775951026041.png</h4><p><a href="https://diysolarforum.com/threads/eg4-12000xp-rs485-terminals.123716/#post-1793427" class="js-lightboxCloser">yam404 · Apr 11, 2026 at 4:44 PM</a></p>">
What I do have is the green terminal block above.
My questions:
1. Are COM1 and COM2 on the green terminal block the RS485 A+ and B− lines?
2. If so, which is A+ and which is B−?
3. Is there any conflict with the batteries already using BAT COM, or are these completely separate?
Goal is to connect a USB RS485 adapter to the terminal block and read inverter data locally via Modbus.
