jm0278 avatar image
jm0278 asked

Multiplus-II AC Input Current Limit -> Per Leg or Total?

I've got a new installation connected to grid power. Does the AC Input Current Limit setting limit power on L1 and L2 individually or does it limit the total amount of power available for L1 and L2 combined?


Multiplus-IIcurrent limit
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2 Answers
mattylight avatar image
mattylight answered ·

I came here for an answer to the same question. So far I've only been able to get the input current limit to function on L1 but not L2. Kinda defeats the purpose of the ICL. Have you found an answer in the 7 months since you posted?

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derrick thomas avatar image
derrick thomas answered ·

You must have the 2x120? When connected to split phase the current limit is for each phase, L1 and L2, but power assist only applies to L1 so essentially the limit only really applies to L1 since you could theoretically pull more than the current limit on L2. When connected to single phase the MP2 will ignore input on L2, pass thru power on L1, and combine L1 and L2 outputs. Thus, the current limit will apply to L1 input only but L1 and L2 outputs combined.

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houlster avatar image houlster commented ·

This is not what I see with my 2x120 & split phase. When connected to split phase, the current limit applies only to L1. L2 will happily draw whatever current is needed for whatever you have turned on that's powered from L2 at the panel.

Say your current limit is 10A, L1 will draw up to 10A only (Power Assist makes up anything over that). But L2 CAN take up to 50A, depending on your loads and whatever the breaker on the supply is. So, up to 60A total draw from input.

When connected to single phase, it works like you said. L2 IN is cut off and the L1 output powers both L1 & L2 to the panel. So yeah, since L1/L2 at the panel is all powered from the L1 output of the inverter, the TOTAL current from the input is limited. In this example, it'll pull up to 10A only from the input. Anything over that is handled by the Power Assist, regardless if the load is on L1/L2 at the panel.

I'm actually not sure what happens here if Power Assist is turned off though. I *think* it will allow more than your Current Limit through. It just won't let the charger pull the current over the limit. It seems like the MPII can't actually *stop* more current than your limit from coming in. What is does instead is use Power Assist to provide the difference between your set Input Current Limit and the current power demands so that the actual shore / input amps doesn't go over your limit.

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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

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