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rjoustra asked

Multiplus 12/3000/120 Overloads in a grid loss

Ok I will try to be as clear as I can.

I have 2 multiplus 12/3000/120 in a split phase config.

10 100ah Battle born lithium batteries with a shunt in two separate (5 qty ea) battery banks routed and fused to a single 1000amp terminal block

Battery Cabling is 4/0 Windy Nation and I will admit it is on the outer limits of length.

Inverter Cabling is 2/0 Windy Nation X2 from inverters to same 1000amp terminal blocks noted above.

AC units have softstarts but are already running at the time of the outage

The inverters will handle both AC units for many hours if I shut them down first then transfer power to the inverters and then turn the AC units back on. So they are absorbing the in rush from the compressors nicely just won't transfer it.

Problem: Inverter will not ups a 10-14 amp load on either or both inverters. If I am running say a 1000 watts or less there is no issue.

Observation: In VRM downloads I can't find anywhere the battery voltage dropped too low or the temps on the inverters at the time of the outage was 38C so according to specs should be able to handle 2200w each, no DC ripple, nothing I can see for the inverter to shut down.

Question 1: What else might cause this shut down. Could cabling being at the edge of acceptable lengths cause this but not show any indication of a cut off in VRM

multi phase
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Mike Dorsett avatar image Mike Dorsett commented ·
If you are getting a volt drop on transfer, this will be too brief to show up in VRM .

You would need to use a voltmeter to test this - some digital meters are also slow in sampling and would not show the true result. Try switching the meter to AC and measure the disturbance. The only way to do this accurately is with an oscilloscope.

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