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kevinc-63559 avatar image
kevinc-63559 asked

Multiplus-II 12/3000/120-50 120V Input current limit

New owner of the title unit. Would like to set the input current limit rather low, like to 3 amps, in order to utilize battery power for the few hours a day where I draw more than 3 amps from the grid.

I looked for the lower limit in the often quoted spreadsheet, but this unit is not listed. My Cerbo seems to think the lower limit is 9.5 amps, since anything I set below that defaults to 9.5.

I don't have any Cerbo notifications regarding the unit, so presume its at current firmware levels?

(did get one on my MK3-USB which is quickly upgraded).

Per Cerbo screens, this is Product ID 2705 at firmware level 508.

charge current limitmultipluss ii
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JohnC avatar image
JohnC answered ·

@KevinC_63559

Indeed your 2705 has somehow missed inclusion in that list. But there are similar sized models that show 7.5A and 9.5A. I think you can confidently assume yours is 9.5A from your attempts.

I note from a previous post you describe your system as a 'UPS'. Not sure what you're trying to achieve here, but if you can define it there may be other ways to approach it, like the Ignore AC functions.

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kevinc-63559 avatar image kevinc-63559 commented ·

This is a super simple setup of the Multiplus connected to a pair of 12V LiFePO4 batteries in parallel. Grid AC comes in from a wall socket (thus the grid limit), AC goes out via the Multiplus. typically from the Grid, or from the batteries in case of a Grid outage. e.g. Its a UPS with a heck of a lot longer run time than my previous APC could provide, and with batteries that don't get damaged by being drained.


Its also my "first look" at the current technology. Phase 1 if you will. Phase 2 will be wiring in a pair of MultiPluses to provide 240V split phase to my entire office, with a 48V battery bank. Phase 3 will be adding solar to the Phase 2 solution. I've learned a lot along the journey so far.

In any case, now that I have the system, I'm playing around. Although I typically only pull about 3 amps off the system, for a few hours a day I pull around 4.5 amps. Be nice to supplement that extra 1.5 amp draw via the batteries, then replenish afterwards. e.g. If I could set the AC limit to, say, 3.2 amps, the system would work as desired.

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Paul B avatar image
Paul B answered ·

on the cerbo - under setting select your multiplus II unit and then you should be able to see the input current limit, change this to 3 amps and this will mean that it will never take more than 3 amps from the mains.

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kevinc-63559 avatar image kevinc-63559 commented ·
I know what the basic function is... I'm telling you it will not accept 3 as input, reverting to 9.5 when I hit enter.


I tried Victron COnfigure as well, and although it will accept it, Cerbo still reports it at 9.5.

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derrick thomas avatar image derrick thomas kevinc-63559 commented ·
9.5 amps is the low limit on that unit with power assist enabled. It will not go lower.
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