Parallel Mulitplus II units show 0 amps input

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ken-wagner asked May 14, '24

Parallel Mulitplus II units show 0 amps input

I have two Multiplus II units wired in parallel, and the system worked fine until performing a remote firmware upgrade to version 510. After the update when running with generator AC input, I no longer see any current values on the L1 or L2 input. We see a input wattage (not sure how) and correct voltage. The output current readings show a negative value and the units no longer support the power assist function. AC power load values decrease to incorrect values while using the generator input. While operating in inverter mode all values are correctly displayed.

multipluss ii

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Answer 1 · 2024-05-15T00:06:42Z

ken-wagner answered · May 15 at 12:06 AM

Note Input power with 0 current, output current is negative value

screenshot-2024-05-14-75717-pm.png (63.3 KiB)

screenshot-2024-05-14-75741-pm.png (62.1 KiB)

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Answer 2 · 2024-05-15T00:24:55Z

Kevin Windrem answered · May 15 at 12:24 AM

You say these units are connected in parallel but the screen shots indicate a 2-phase configuration. That could be causing all sorts of problems

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Answer 3 · 2024-05-15T01:50:03Z

ken-wagner answered · May 15 at 01:50 AM

Hi Kevin, The L2 was added in a firmware update in the Multiplus II / Cerbo Gx. The Multiplus II has two input lines, however, when in inverter mode, it ties L1 to L2 for split phase operation as in a RV application. Another post help us solve this problem, it is a faulty external current sense connector on the Multiplus units. It would fail to make the connection internally that told the circuit to make use of the internal current sense device. The fix was to simply plug and unplug an audio plug in and out several times which caused it to make the necessary connection again.

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