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Multiplus II + ESS + Power Assist not working as I expect when minimum SOC is reached.

Hi all,

So i'm running into a bit of a issue with the behavior of the system. I'm pretty sure this is intended but still wanted to ask for options.


Little introduction

I have a 3 Phase system setup (3x Multiplus II) backed by 30kwh lifepo4 batteries which are charged by the MPPT RS inverter. I'm using a EM24 to measure grid power even though my whole house is behind the victron installation.

My grid connection is 3x25A and one of the goals of getting this system is to not have to upgrade to a 3x40A connection which would cost me 700 euros a year. My house is fully electric (no gas connection), electric cooking, electric heating, electric car, heatpump for pool.

This means I have a lot of consumers that if turned on at the same time can trip the breakers. Since i sell power to the grid for 1:1 (untill 2025), the main reasons for the system was 1: UPS functionality, 2: saves 700 euros a year on a higher grid connection bill. 3: Was building a new house, so it was the perfect time to get all the wiring in and 4: Being ready for when i no longer sell to the grid at 100% rate.


The issue

I'm generally running a 75% Minimum SoC with a 0W Grid set point. Excess PV is delivered to the grid. Usually in the evening it reaches the minimum SoC. Once it reaches the minimum SoC it seems like input current limit is completely ignored. This means if when the minimum SoC is reached, my breakers can trip when multiple loads are on at the same time.

In my opinion, the input current limit should always be respected, almost as a same priority as grid failure (Since it in 99% of cases leads to grid failure, why else would you configure a input current limit).

The expected behavior for me would be that if a peak load needs to take from the batteries below the minimum state of charge on 1 or multiple phases. It starts assisting on the phases that require it. If there are phases available that have extra capacity left, it can convert AC to DC to supplement the DC requirement for the peak shaving phase. If this is not sufficient (maybe all phases are overloaded) it can take energy from the battery beyond the minimum SoC. Since if it does not do so, theres a risk the grid goes down and having to take from batteries regardless. After the peak load is gone it could top up the batteries back to the minimum state of charge using the grid (not beyond). Since I want the DC coupled solar only to top the battery up to 100% minimizing inverter losses.

Ideally, i'd want to have a minimum SoC for self consumption and a second minimum SoC for power assist to minimise inverter losses. E.g. discharge to 75% for self consumption, then discharge to 50% for peak shaving. If battery is at 50%, still allow peak shaving however when possible use grid to charge back to 50%.

Is what i'm experiencing intended?

Does anyone have any advice or recomendations?

Marco Nijholt asked
shaneyake commented ·

6 Answers

Multiplus goes into Passthru when AC-IN overloads

Hello,

I've a system containing 2 Multiplus II 5000, a couple of MPPT, Cerbo GX and Pylontech batteries.

The system is configured as Single Phase parallel System and all load is connected to AC1 out of the Multiplusses.

PowerAssist is active and also a AC Input Limit of 30A is configured through VictronConnect (with MK3 Adapter).

ESS Assistant is loaded onto both Multiplus.

ESS Mode is configured without battery life with a minimum SoC of 20% in the Cerbo.

Every device updated to the newest Firmware.


When the SoC goes down to 20% the Multiplusses start using energy from Grid. They are in Bulk mode.

That's what I expected.

Problem:

When the AC Load is higher than 30A the Multiplusses go into Passthru mode.

This is what I don't expect.

What I would like instead:

When the AC load is higher than 30A the Multiplusses should use 30A from AC-in and use the rest from the Battery. When the load is going back under 30A the Multiplusses should fill up the batteries back to 20%.

klandos asked
klandos commented ·

6 Answers

Power Assist - Limits and Voltages

I have a 30A camper at a seasonal site with terrible power. My plan is too get a MultiPlus with PowerAssist to limit the shore to 12A and have the batteries make up the rest during peak demand. This would be about 5-7amps at various times of day, and up to 3 hours at a time.

A) Does the PowerAssist have any limitations outside of my battery bank being sized to do this, time wise?

B) I know it supplements current, but what does it do with the voltage. Our park is terrible, I run a Hughes just to keep the voltage above 100V in the trailer during full load (17A with the AC on, no inrush I have a ramped soft start). If I can limit the shore to providing 10-12A we would be at 105-110V during the worst periods. Does the Assist also attempt to boost the voltage to 120V or just match the incoming.

The spec sheet shows charger voltage can be down to 95VAC incoming but doesn't say much about what the assist does with that.

I just want to make sure the unit I pick can handle what we are asking it to do. I had limited experience with the ICGP2000 and its PowerShare would treat the 105VAC coming in as a problem with shore and constantly fully switch us over to batteries.

Thanks!

Ryan

summerland asked
pwfarnell answered ·

1 Answer

Power Assist Issues

My installation consists of 2 Multipluses 12/3000/120 (in parallel), Lynx Smart BMS, Cerbo GX, 4x Victron Lithium 330ah batteries., and 4 Smart Solar 100/50 with all DC loads on a SBP. All components have the latest firmware. This is on a sailing catamaran.

After months of flawless performance, I’m experiencing some intermittent strange behaviors that are occurring more frequently with the power assist capability of my system. I get slightly different behaviors if I’m on shore power vs generator power.

  1. Shore power: Occasionally I’ll wake up to see my batteries are somewhat depleted as the system is using assist unnecessarily. You can see in the first picture where my Multipluses are accepting only 1185W of power, but my AC loads are 1918W. My input limit in this case is set to 25amps as I’m currently on a 30amp shore pedestal. Additionally, I’ll observe that the reverse polarity light on my panel glows slightly brighter with increasing loads. NOTE: When bypassing the Multipluses, or while solely inverting power, the reverse polarity light is completely dark.

    [image]

  2. Generator Power: After degrading performance which started similar to what I’m experiencing with shore power above, the system has mostly stopped accepting generator power, and I get a fault. See picture 2. I found I can sometimes trick it by turning off all AC loads prior supplying generator power in. But I’ll often get the little triangle error on the device list page of my cerbo. However, I don’t see any actual notifications for my multiplus. I also experience glowing reverse polarity light on my panel. In the tricked mode, none of my air con units will start (even the 8kbtu). In my troubleshooting, I removed the ELCI breaker from the output of the generator and it appears I’m back to flawless performance. ABYC codes require an ELCI, so I’d like to return it to service.

    [image]

Has anyone experienced similar error conditions? Could it be that my Generator’s output ELCI has failed and is causing the inconsistent behavior? Could I have some other grounding issue? Like possibly Ground Relay issues?


brucevanderbilt asked
trevor-bird commented ·

5 Answers

Using Multiplus to reduce generator fuel consumption

Hi, I have a multi-+2 3000 W charger/ inverter connected to 1450 amp hours of battery storage at 12v, I'm trying to figure out how to configure the multi plus so that I can use the stored energy in the battery to supplement the the generator to reduce fuel consumption for a longer period of use time. I tried this using power assist settings in reducing the incoming amperage from the generator so the converter would supplement power, that worked great until the loads dropped below the set point of power assist in the battery speaking to charge off of the inverter.


Does anyone have a suggestion on how this can be configured properly so I can use/consume the energy stored in the battery and supplement the generator for a longer period of runtime and fuel savings? Ideally I would still like the ability to use the MPPT
to charge the batteries while in this configuration. Also I am always not on generator and need to be able to switch back to normal operation when connected to the gird/shore power. I tried to use the ESS assistant but is not recommended and did not work well with the generators.



Jeff Kellner asked
kevgermany answered ·

1 Answer

multiplus ii Generator disconnect

I have a 2,8kW max (10A) "non inverter/AVR" generator connected to Easy Solar II 24/3000. This generator can power directly 2,5kW Bosch AXT 25 TC branch shredder for hours.

Battery is first charged 100% by generator, which charges 35A with Weak AC option ON, and 50A without it (which is max for my battery, also my battery has 200A constant discharge rate).

Also i have 1,2kW of solar panels in good sunlight, but sadly as soon as generator is connected, SmartSolar stops supplying current to the system (solar input stays at 70V but current goes to 0A).


I start 800W heat gun, generator tries to ramp up rpms but inverter almost immediately disconects the generator.


I have tried lowering AC1 input current limit minimum - 3,5A (and also maxed all the way to 10A). Doesnt work still.

Settings:

UPS OFF (also tried ON),

AC1 input current limit - 8A

Dynamic current limit ON (also tried OFF),

Accept wide frequency range ON,

AC low voltage disconnect 180V (and also tried 210V as suggested in the manual),

Power Assist on, assist factor 2 (also tried 1 and 1.5)

Nothing works.


Is the generator just too slow/low quality or are there any other settings i can try to keep generator connected until it revs to suitable speed/voltage?


jj-o-jj asked
netrange commented ·

1 Answer

No current or power limit in scheduled charge mode

Does anyone know how to explain the setting of current or power in programmed charging mode ? Apparently there is no current or power limit.

nostromo asked
nostromo edited ·

2 Answers

Powerassist with priority to solar

Hi,

I have a grid-connected system (no feedback) with Multiplus 3000/24/70 and VenusGX.

I can run most of my electronics from the inverter, but when it comes to the washing machines (2000W) the inverter can't cope since there is additionally some 200W to 400W AC loads connected. So, I have set a condition to switch to grid if AC loads > 1800W. But to take advantage of Solar, I have put a limit in the AC input in the order of 3 to 6A. This will make the System use Powerassist and use much of the Solar (either direct or from battery) and get another part of energy from Grid.


The issue that I want to address is that if I want to really take advantage of solar - I have >3000Wp installed, I would like the inverter to fetch from grid only what it really needs to complete the AC loads needs. That is, use the Maximum AC load that I set as condition to switch to grid to be the inverter set point (in my case 1800W) and get the remaining from grid.

Instead, what currently happens is that system will use the maximum that it can from Grid and then complements with Solar. I would like this in reverse...

Is there any way to do it?

(note: I can't use ESS...)

Elimac asked
fedya-skitsko commented ·

1 Answer

Multiplus-II: Input current limit ignored after heat warning

Hi all. My Multiplus-II (24/3000/70-32, fw v.487) is acting strangely today. Been fine-tuning my setup since august last year and everything have been working perfectly. I am using Venus OS large with node-red to control most functions of the setup, which includes two shunts (one to measure battery current and one to measure PV current), several off-brand MPPT's, and a big battery bank of 32 x 75Ah AGM batteries.

Today i received a warning e-mail from my node-red system about a temp warning. I went to the unit and checked, it was warm, very sunny day which means several dump loads have been running very long with a total of 2 kW, not surprising that it got hot, but after removing the lower grill to ease air flow the warning went away. My idea was next to help it a bit by enabling the grid and power assist on 3.5 A to take some of the load off the inverter for a while. I have used power assist very much and it has always kept the limit, but to my surprise, even though I double checked the setting in the console, when I stopped ignoring AC in, it went up to 8 A power assisting, then switched to passthru not inverting at all, then back to power assisting 7-8 A and to passthru and flipping between the two constantly. Wut?!, I ignored AC in which had it inverting the whole load perfectly fine.

In the evening when one dump load had turned off and the load became lower (around 1500W), I tested the power assist function again. It is set at 3.5A still and it started assisting with 8A, then after a few seconds started going down and finally settled at the level I am used to seeing. Now it goes to the "right" limit straight away when stopping ignoring AC in, working as it has always been before.

Anybody have an idea what caused this? I merely want to understand it, I believe it is a good idea to install an extra fan to cope with these cloud-free sunny days, but why the power assist function would become non-functional because of a bit of extra heat is beyond me. Note that it never went into temp alarm, only temp warning...

Regards,

MrHappy.

mrhappy asked
mrhappy commented ·

0 Answers

Multiplus-II PowerAssist and self-consumption

Hello,

If the multiplus-ii has an AC input with powerassist setup, in case the ac input did not pass the threshold and the powerassist did not engage yet from the multiplus what is the self-consumption of the unit ?

Bonhardt László asked
acke-ee-retired answered ·

1 Answer

assist current boost factor using

Last week I installed 3 phase, using 3 quattro 10KVA,

there are only batteries without any AC input.

in these home there are an air-Conditioner 3.5HP, When running the lighting fades and returns after a second, Is there a way to stop it? I read that it is recommended to set the assist current boost factor to 2.

thanks.

muhamad asked
Alexandra commented ·

2 Answers

System not recognizing shore power

My system is not recognizing the 30 amp shore power. This happened overnight for some reason. Help!!

jills asked
Alexandra commented ·

0 Answers

Multi RS Solar 48/6000 Power Control

I have been looking at the Multi RS Solar 48/6000 Power Control setting in the manual and cannot fine the minimum 230 volt input current limit lowest setting. In the Technical Specifications of the manual I cannot see it . I have seen the input current limit in the manual for my MultiPlus-II 48/5000/70-50 which has a current limit settings of 6 A – 50 A

Does anyone know what the lowest "maximum current" setting for the Multi RS Solar 48/6000?

bolie asked

0 Answers

Add PowerAssist spec to the data sheets and manuals for all inverter/chargers

I have changed the title of this question. I believe the issue is the documentation but need this verified by Victron engineers.

Looking at the 120 volt Quatro manual, it states the the maximum power assist is 5 KVA or 42 amps. The 230 volt Quatro manual states different power assist maximums for each model.

Obviously, 5 KVA of assist on the 3000 VA Quatro is not correct and should be 3 KVA.

Is the same true for the 10000 VA Quatro: max PowerAssist of 82 amps?

PowerAssist is usually described as the AC input current limit plus the inverter's maximum output. So for a 10000 VA Quatro set for maximum input current that would be 184 amps. Is this the correct number?

I can see there may be other limits in the design that might reduce this such as circuit board traces or output connectors.

Interestingly, the maximum output current or power is not specified on any models I looked at.

AC 2 out has a limit of 100A due to the relay in that path but AC 1 has no relay

Is the AC-out-1 maximum current always the sum of the input current and the maximum continuous power divided by the system AC voltage?

OR is there some limit in the circuitry that limits the output current to a lower value?

I have found other inconsistencies in the manuals in the AC-out-1 section where the output breaker and wire sizing is discussed. For example, the manual for the 120 volt Multiplus 3000 VA unit calculates the maximum output current based on a 230 volt AC voltage not 120 volts.

I would like to see a "Maximum AC 1 output current" and "Maximum AC 2 output current" specs added to the data sheet and anywhere else the specs are tabulated. I would also suggest Victron update the AC-out-1 discussion to make it more clear what these values will be for each model.

Also, the manuals for all 120 volt models should be reviewed to make sure a 120 volt AC system voltage, not 230 volts is mentioned everywhere.

Kevin Windrem asked
Kevin Windrem edited ·

1 Answer

easysolar 12/1600/70-16 MPPT handling big loads

Hi,

actually I've got a MP2 48/5000 and 14KWh battery system working in my house so some ideas of what might work do already exist... but:

I've been asked to build a smaller/cheaper solution for a friend and so I found the easysolar 12/1600/70 -16 and this would do for 80% of the usecases... but what happens if a load greater than 1300W is connected?

The AC1 will be connected via 16A fuse to (normal) grid, Batteries charged via MPPTs...

I'd like the inverter to handle the smaller loads in order to keep the grid-cost low.

When a big load comes, does the inverter deliver 1300W and rest comes from grid or will system go to overload?

And is it possible to connect the easysolar 12/1600.... (via GX) to VRM Portal for better remote control / Service?

Thanks for any information about the load handling / VRM connect.

Cheers,

Jens





jbrex asked
jbrex edited ·

2 Answers

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