Why is my Multiplus inverting but not charging?

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outofthenorth asked Dec 20, '21

Why is my Multiplus inverting but not charging?

I have a Multiplus 12/3000/120. It works well as an inverter but when I plug it into 15A shore power, it does not charge my two 206Ah LiFePO4 batteries. I also have an Orion DC-DC charger and a SmartSolar MPPT and I have been using them successfully to charge my batteries but when I try to use the charging function of the Multiplus, the "Mains On" light flashes to tell me that "the AC output current is equal to the preset maximum input current."

I have tried setting my maximum input current to different values but that does not change the situation.

Can anyone give me insight?

battery charging

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outofthenorth answered · Jan 10, 2022 at 05:07 AM

I connected the MC3 and went through every single setting and it turns out that the conditional AC input control was activated. I read on the Victron website the default is for it to be deactivated so I turned that feature off and immediately my batteries started charging through the inverter. Not sure how that got turned on but I am thrilled that the problem seems to be solved.
Thanks so much for your help.

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sdurland commented · Aug 10, 2023 at 01:37 PM

We have a new MultiPlus and are having the same issue as OutoftheNorth described last year, where the MultiPlus inverts fine, but does not recognize our 30 amp connection for charging and AC power. Their solution was to deactivate the Conditional AC Input Control (their's was set on Activated). I want to see the status of that parameter, but I can't find it on the VE Config 3 software. I'm sure I'm over looking it, but if any one can point me in the right direction I'd appreciate it.

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Answer 1 · 2021-12-20T15:17:18Z

snoobler answered · Dec 20, 2021 at 03:17 PM

The charger can be turned off. Can you access the unit through Victron Connect or VEConfig?

Given the error message, if you draw more current than the AC-input limit is set to, you will not get charging.

The same transformer is used for both charging and inverting. The unit can't invert on the output and charge separately from the input. It's passing through the AC-in to loads and charging with surplus.

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outofthenorth commented · Dec 20, 2021 at 06:37 PM

Hmmm, there's a lot to consider in your answer.

I'm using Victron Connect to communicate with my devices.

The only load using current are my 12V batteries, there was no AC load.

I had switched the unit to "Charge only" when I got the error.

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Answer 2 · 2021-12-20T20:16:45Z

snoobler answered · Dec 20, 2021 at 08:16 PM

Ah... you likely need to limit your CHARGE current, so that it doesn't overload the AC input.

Try reducing your CHARGE CURRENT to something conservative, around 30A. If this works, keep increasing until it stops, then back off.

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Answer 3 · 2023-07-15T19:13:25Z

Tom answered · Jul 15, 2023 at 07:13 PM

Thanks for posting...my Multiplus has not been charging for some time and seller tech support has not been able to help me, except to open a repair RMA. Recently updated to v505 and connected to (3) Victron Lithium SuperPack (200aH) batteries.

Interesting that the default charge rate is 90 amps when the Multiplus 12/3000/120-50 has an input limit of 50 Amps. This sounds like a firmware issue that could be resolved with an upcoming patch.

Curious that the Victron's Lithium SuperPack batteries are not listed in the battery drop down menu since they are a Victron product and do not use a BMS.

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klim8skeptic ♦ commented · Jul 15, 2023 at 11:14 PM

@Tom "Interesting that the default charge rate is 90 amps when the Multiplus 12/3000/120-50 has an input limit of 50 Amps."

Just be aware that the 50 in the model number refers to the current limit of the AC transfer relay.

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kevgermany ♦♦ klim8skeptic ♦ commented · Jul 16, 2023 at 05:12 AM

@Tom input current limit is at the AC voltage, charge current limit is at battery voltage. They're not directly comparable until you do the math.

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ejrossouw commented · Jul 16, 2023 at 06:20 AM

@Tom The default setting is 75% of the maximum 120A and 90A DC is only about 5.6A AC so well within the 50A transfer switch capability.

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Tom ejrossouw commented · Jul 16, 2023 at 04:29 PM

Thank you ejrossouw and kevgermany...appreciate the explanation.

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Answer 4 · 2024-01-14T01:21:59Z

gregoconnor answered · Jan 14 at 01:21 AM

Hi Thanks for this site. I post for your interest.... I have installed 7 Victron Multi 12/3000/120-50/ii in RVs now and this is the first rv test we had an issue. I too found no charging however the inverter worked great. I decided to just install a Victron Multi from a working rv to get the customer on their way only to find out the 4 dc input lugs were lose. Yes I have a screw loose. (torque down and all was good) My test of inverter draw was a 1200 watt heater for 1 hour and a residential refrigerator running in the background. I can see that the draw into the multi inverter from batteries was probably 150 amps @12vdc. ... I lowered max charging to 30amps out as suggested here for a test to see if charger would start up. no luck. on the multi screen it would go from bulk to proving both float and Absorb lights on and nothing went into the batteries.

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