question

redwood avatar image
redwood asked

Multiplus not using full shore power limit

Running the air conditioner in the RV with AC input current set at 15 but muliplus will only use around 9.5 and is using power assist to make up for this. See screen shot 1

If i turn off power assist it will then fully uses shore power and even has a little left over for battery charge. See screen shot 2

I have tried turning on/off the weak ac and the ups functions. How can i fix this? I need to have the power assist on so even though with it disable it does pull the full amount from shore current. With it off i am unable to run other interment ac loads.

MultiPlus Quattro Inverter Charger
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idahospud avatar image idahospud commented ·

I am having the same problem on a multiplus 24/300/70 hope there will be a solution soon

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jim-streit avatar image jim-streit commented ·

Hello, I'm seeing the same thing with my MultiPlus 12/3000/120. When set to charging only mode it appears to pull the correct amount of power, but I really need to run in inverter mode so the batteries can make up the extra power if needed. Any way to get a response from Victron if a setting change can fix this? Thanks

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43 Answers
Mark avatar image
Mark answered ·

As your using shore power (not a genset) try disabling 'dynamic current limiter' and see if that resolves your issue.

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redwood avatar image redwood commented ·

I have already tried disabling dynamic current limiter and that does not fix the problem.

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JohnC avatar image JohnC ♦ commented ·

I'd also untick 'Overruled by remote'. Even if you have no remote..

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idahospud avatar image idahospud commented ·

I am having the same problems as Redwood and have tried both suggestions without prevail.

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ben avatar image
ben answered ·

I can't help you, except to share that my Quattros also do not ever reach the setpoint for the shore limit. Instead, they stay somewhat below that setpoint, perhaps because they want to keep a buffer to ensure if the load jumps quickly that they can deliver battery assistance in time before the shore current exceeds the setpoint.

However, my two units seem to stay about 2A below the shore current setting, not 6A like yours. I'm not sure how they decide how far below to run.

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redwood avatar image
redwood answered ·

I have tried all that and it does not fix the problem. Any help on here from Victron?

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boekel avatar image boekel ♦ commented ·

Have you tried lowering the 'boost factor'?

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alan avatar image
alan answered ·

Maybe set the current limit a little higher?

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redwood avatar image redwood commented ·

If i set a higher current limit of 20 then it will overload the generator with battery charging.

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alan avatar image alan redwood commented ·

Limit the charge current in the charger tab then?

I know not ideal but if it works.

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redwood avatar image redwood alan commented ·

But then if when i turn the microwave on instead of using power assist it overloads the generator due to the shore current being set to high.

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alan avatar image alan redwood commented ·

wasn't the problem with power asssist on it wasn't drawing to the limit set?

Did you try it and the microwave overloaded the genset?

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redwood avatar image redwood alan commented ·

When the microwave is turned on then it will jump up from the 9amps and try to take the 20amps set and that overloads the generator.

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Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hello, The screenshot 1 shows you have the [overruled by remote on], this means that however the setting in Ve configure can be set at 15A, if the remote is at a different setting it will follow that. So the first question, do you have a remote panel and if yes, whats the setting there?

(if not the setting is not relevant by the way)

At powerassist the behaviour of ACinput current can be a bit different then without powerassist active as then things like powerfactor of the load (as the inverter adds energy from the battery).

So what is being drawn exactly depends on the load type as well.

Beside this the ACinput setting has a "margin" built in to prevent tripping the incoming fuse. (about 10%).


A few remarks on comments made;

Dynamic current limiter allows a graduate built up of power from the ACin towards the setpoint after there has been a while that there wasnt much usage of the ACin. This is to allow (smaller) generarors to built up thier power.

UPS function is the level how critical the unit checks the quality of the incoming power to protect its loads at AC2 out (there is no relation on used power from Acin)

Weak AC is the setting which is used when the incoming AC power has a sinewave which is so distorted that the inverter is hardly capable to synchronize. lets say even a step further the the UPS function. At this setting the sinewave is used but limited which will result in less chargepower.



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redwood avatar image redwood commented ·

I do not have a remote panel.

I understand the margin of about 10%. But its only using 9.5 amps of the 15 amps available. That is a LOT more then 10%

It makes no difference with week ac on or off

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redwood avatar image redwood commented ·

No remote panel. I understand the 10 percent margin but only using 9amps of the avialible 15amps is way more then 10% Please help me fix this issue. Thanks

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pat-e avatar image pat-e commented ·
Is there any change/fixes planned yet? Uncontrollable power assist is still a major bug for the entire line of inverters Multiplus/Quatro. I was unhappy to find that upgrading to a more expensive Quatro 5K has the issues as the multiplus. Because my load requires 100 watts more than my genset can handle I have feed 900 watts from the batteries with power assist should not be seen as a working feature. Please tell Victron is looking into this?
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nocolorsadded avatar image
nocolorsadded answered ·

I am experiencing the same issue with my MultiPlus 12/3000/120 in my RV. I have attempted to reach out to a number of people at Victron and never quite get a answer for this. I have had other IC's in the past with power assist like function and none had this issue till I "upgraded" to the Victron MultiPlus.

We have 300AH of lithium batteries onboard, we want to run the air conditioner and some other loads that are above the peak of our Honda eu2200 inverter generator. We literally selected the MultiPlus because of the Victron Honda (can't find link) and White paper Using the MultiPlus to reduce operating cost of a generator white papers. This is exactly what we had been doing in the past with other IC prior to swapping to the Victron.

The core issue is power assist will allow me to draw from 7.5-~11 amps from the generator but no more. The strange part is if you lower the input current from 10 to 9 amps it honors the limit correctly all the way down to the limit of 7.5 amps precisely.

However, when you increase the max amps for power assist, above ~11 amps, it does not linearly increase. That makes no sense to me at all, I can't figure out why.

The net effect for me is if it is hot outside and we run the air conditioner, refrigerator and some other AC loads I can't keep up with the power loss. So the MultiPlus is always in power assist, generator limited to ~10 amps and if I am not careful I will deplete my battery bank by evening.

Running from the generator starting at 18 amps (max) it works. However, I can't run it that hard for more than 30 minutes as per Honda. ~1.2 amps less pulled from generator.

You can see below that I have selected 16 amps. ~1.1 amps less pulled from generator.

Lowered to 14 amps, it falls off and will be the same till the input current is less than 10 amps. ~3 amps less.


So now I have the current limit at 14 amps, if I were to increase it, the AC in will remain at ~11 amps till I set the input current above 18 amps and start to bring it back down. Something is wrong here for sure...


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ben avatar image ben ♦ commented ·

I agree. It looks like a bug.

I will try to see if I can replicate that behavior the next time I’m on grid power. I’m pretty sure mine don’t do that, though.

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nocolorsadded avatar image nocolorsadded ben ♦ commented ·

I can replicate this on multiple generators and on grid power. Strange that the limits are not liner from 7.5 amps up. That is what makes it feel like a bug.

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redwood avatar image redwood commented ·

Exactly the same problem that i have! Victron have you fixed this yet?

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pat-e avatar image pat-e redwood commented ·
Same issues with Quatro 5K
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pganguet avatar image
pganguet answered ·

I believe this behavior is by design. There's lots of data on different current levels for power assist depending on the inverter model. What is not documented is the minimum amount of power assist you get once the current limit setting is reached. For example, my system has two 3k inverters in parallel. My system allows a minimum power assist current setting of 15a. So if I draw 16a, power assist will kick in. But it will not simply add 1a. In my installation, the minimum assist is about 8a (or 500w per inverter). So what that means is now half of my load is being run by batteries and the other by the AC source. Only when the total load is about 1000w HIGHER than the input current limit setting, will my system use all available generator power.

Remember, each inverter has a minimum contribution of about 500w when power assist activates. Or at least that's my experience over 4 installs.

Its obviously not preferred, but at least it can help to understand whats going on.

The only "Almost workaround" is as previously posted that once power assist kicks in, increase the current limit by about 4a. But if the big load cycles off, all hell breaks loose!!

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nocolorsadded avatar image nocolorsadded commented ·

What does not make sense to me is that if you have a minimum power assist, why it is not consistent through the maximum amp range? If it is always 4a for a single Multiplus, then it should be that way though the entire amp range not just part of it.

It is also inconsistent that it fails when increasing the maximum amps for power assistant, but works better when decreasing the maximum amps.

My issue is I have a load that is 18a, I want to set the max amps to 13a and use the rest from battery (5 amps). However, I can't get the Multiplus to do that. I can set anything between 10a - 17a.

So I am crippled when trying to plug into a 15a outlet in a home in N. America for example. Either I have to pull more power then the outlet can handle OR so little that I run my batteries dead by the end of the day.

I have tested Xantrex and GoPower IC's and they don't exhibit this same symptom, it must be possible to adjust in software somehow. Still seems like a bug to me.

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Kevin Windrem avatar image
Kevin Windrem answered ·

I am experiencing the same issue. Multiplus Compact 2K/120v. I first noticed it running on generator when the air conditioner ran BUT have eliminated both of these as contributors.

I did testing on shore power (for a stable power source) and with a space heater (to eliminate power factor issues and long compressor cycle times). The space heater draws 1280 watts.

The Multi stays in Assist mode at any Input Current Limit setting under 12 amps. This results in about 980 watts from shore power and the rest from battery via the inverter. Input Current Limit does not affect what's drawn from shore power. (When testing with my air conditioner which draws 1350 watts while running, the incoming AC power was 1050 watts.)

If Power Assist is turned off, this issue does not exist. The Multi simply operates in Pass-Thru mode. That's OK when on grid power but not when running from generator.

Adjusting Assist Current Boost Factor changed the input current that kept the Multi in Assist mode: <12 amps for boost factor of 2.0 or 3.5, <10.5 amps for boost factor of 1.0,

Dynamic Current Limiter exacerbates the issue. I must set the Input Current Limit to 14.5 amps to avoid the situation where the Multi remains in Assisting mode. Dynamic Current Limiter is essential when running off a generator.

I'm running a 2000 watt (peak) generator on propane. The best I can do is 1250 watts (10.9 amps) at 4000 feet where I'm likely to camp and still need the air conditioner.

The battery charger portion of the Multi often draws 1400 watts from shore power/generator which is more than the generator can supply.

I can't see a way to set the Multi to avoid this behavior and still prevent my generator from overloading. Any ideas?

It would be nice to rely on the settings we are given to accurately support saggy sources such as a generator. So are these issues bugs? If so, when might we expect fixes? If not, what guidelines can Victron supply for proper integration?

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nocolorsadded avatar image nocolorsadded commented ·

I have also checked all the settings and it is not a settings issue, it is a bug to me. The PowerAssist should allow the input current to linearly increase from 7.5a up for those of us using it at 120v. I don't know how we get someone from Victron to help us here!

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Tom avatar image
Tom answered ·

Why don't you wire your Air Con to the Multiplus AC out 2 so it by passes the inverter when plugged into shore power since it seems you do not have a large enough battery bank.

Running the roof top AC on a 15 amp circuit is under powered. You need a minimum of 20 amps to run the Air Con without tripping. I would also guess if you are also using an extension cord attached to your shore power cord you will see a voltage/amperage drop. How warm does that cord get?

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nocolorsadded avatar image nocolorsadded commented ·

To be fair, My Dometic Brisk II is 7.5a with the fan, 11-13a depending on temperature. Heck I run them off my batteries all the time. However the entire point is is we are using PowerAssist with batteries so we can reliably run the fridge, microwave etc. 15a circuit is more than adequate with PowerAssist which is what everyone here is trying to understand why it does not work properly.

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nocolorsadded avatar image
nocolorsadded answered ·

@Johannes Boonstra (Victron Energy Staff) do you happen to have any other suggestions since many people are experiencing the same issue? The core issue is why does PowerAssist does not work from ~12-16a @120v? It works fine lower and above that but not between that range.

Anyone in the US with 15a outlet can't draw more than 11a or so. The same issue is for anyone using a 2kVA sized generator.

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There is no reason (as far as i know) that there is a range in which the PowerAssist wouldnt work. It is a fact that PowerAssist sets it level at about 80% of the setting (to be sure to stay on the "safe "side of not risking to blow the inlet fuse of the shore power.) So settings the AC input limit at 15A has a (more or less) 11A AC input usage as result

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nocolorsadded avatar image nocolorsadded Johannes Boonstra (Victron Energy Staff) ♦♦ commented ·

The issue is it is not a linear which is my issue. When you get around 11A increasing the max current does not work till you hit 18A or so. If you test it, increase by 1A starting at 7.5A and you will see what we are experiencing.

So I spend all day with a minimum of -35A draw pulling from my battery. Currently I have to turn off everything, recharge the batteries and then turn back on the loads to prevent the batteries from going dead. Frustrating to put unnecessary cycles on the batteries the the power is available.

This has to be something with the logic with PowerAssist because when charging I can hit the correct max current input limit as specified.

In my case with a Honda EU2200 I would be happy if I could set max input current to 18A and PowerAssist limit to 14A (80% of 18A).

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Ian Murdock avatar image Ian Murdock Johannes Boonstra (Victron Energy Staff) ♦♦ commented ·

@Johannes Boonstra (Victron Energy Staff) I am also seeing the identical issue as everyone in the thread with a MultiPlus 120/3000/120, Venus GX with a Honda EU2200i Companion with the latest firmware on Victron products.

If I do the math 80% of 18A amps is ~14.4A, the best I can do is 13A. The problem for me is if I start the input limit to be lower say 13A with the load running (air conditioner) and attempt to increase it nothing happens till I get to 18A. If you start at 18A and bring the input current down it appears to work properly (linear decrease as @NoColorsAdded suggested). The problem is as soon as the load cycles the next time you get the same power requirement you get limited again to ~11A. {attaching screenshot showing the same issue on mine}

Effectively on either a standard N. America outlet or generator I am limited to only 60% of the available power.

I would be thrilled if it was 80% of the input current but that is not what we are seeing.

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Johannes Boonstra (Victron Energy Staff) avatar image Johannes Boonstra (Victron Energy Staff) ♦♦ Ian Murdock commented ·

Hi, With a (smaal) generator as a Honda 2.2kW there are also the other criteria that play a role. If Ac input starts beginning to become less stabile, the exact PowerAssist level is less accurate

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nocolorsadded avatar image nocolorsadded Johannes Boonstra (Victron Energy Staff) ♦♦ commented ·

That is understood about the inverter generators but this is happens on grid power as well. I don't think this issue is specific to just generators.

Do you have any other suggestions? I have been attempting for a year to get support from my dealer/Victron. I am just happy that this thread confirms I am not alone.

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blond2silver avatar image
blond2silver answered ·

After reading this post all the way through, I am about to begin spending time and energy testing a portable generator, and would like to know if Victron has addressed this issue or not? When I read this, it has me wondering if I made the right decision in going with Victron's multiplus or not...

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brock avatar image
brock answered ·

I am having the same problem. I have a 24/3000/70 Multi Has anyone found a fix to this. thanks


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jonvoigt avatar image
jonvoigt answered ·

I'm having the same issues as well, I often run all my stuff of generators but find all sorts of issues with the Current limit not aligning with how much current is being pulled. 10% off the setting would be great but It is all over the place, especially around the 15amp mark.

Any updates on this Victron, is it possibly a firmware update that can fix this?

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jim-streit avatar image jim-streit commented ·

Any update if you got this to work correctly? I'm still experiencing the same thing and would love to get this working as expected. Thanks

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jim-streit avatar image
jim-streit answered ·

I know this thread is about a year old, but was there ever a resolution to this? I have a 12/3000/120 in an RV that is experiencing the exact same issue between 11 to 16 amps, when connected to shore power. This is really frustrating when visiting a place that only has a 15 or 20 amp outlet. Just like the others, I'm afraid my batteries are taking a huge hit being used and recharged multiple times a day when running the AC. Is there a tweak, setting or firmware that can be done to correct this? - Thanks

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green-monster avatar image
green-monster answered ·

Has this question been answered yet? I also am trying to use a 2000W generator to supplement the batteries while boondocking in an RV, setting for max input current of (tried 10/11/12/13 Amps), and as the AC cycles on and off, the Multiplus will randomly draw too much power, trip the generator, and then start seriously depleting the batteries to supply the 45amps that I have measured being used while the AC is on.

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leatchr avatar image
leatchr answered ·

Was having a similar problem with a 2 MultiPlus 12/3000/120 parallel system (240v). Tried many variations of firmware / settings etc but was always seeing PowerAssist kick in at very low levels (well before the shore power limit). Eventually realised that the Digital Multi Control was not functioning as expected/documented. When on a 16 Amp shore power connection, I would usually set the limit (via the DMC current limit dial) to 15 amp. When on generator, I would typically reduce this to 10 amp. However, I've noticed in Ve Config (remote override enabled) that a setting of 15 is translated to 7.5 (in each of the master/slave Multiplus). Seems to just divide the DMC value by number of devices but has a lower limit based on devicre. PowerAssist is "per device" so the effect of this is that it will start to kick in at some value (say 10%) less that 7.5 amps. This is not what is expected of course since I actually want it to kick in just below 15 amps.

The Victron documentation (see https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems) is quite misleading because it specifically indicates that on a DMC the current limit (in a parallel environment) is not meant to be multiplied by the number of devices. In my case, to get the best use of shore power and PowerAssist, I need to set the current limit on the DMC to 30 (which writes 15 to each device) and seems to trigger PowerAssist at around 13 amps. Haven't experienced any overloads yet (PowerAssist kicks in before shore power is overloaded). Did adjust the charger max current down just to be sure not to overload when just charging not inverting. If I didn't need to adjust for generator I'd probably just code 15 in each Multiplus and disable the DMC override (in which case the DMC surrent limit is fixed at ""ACin"and can't be adjusted).

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ben avatar image ben ♦ commented ·

Your system is not two inverters in parallel. Your two inverters are in split-phase.

The main issue being discussed in this question is different than the math/UI mixup you are talking about. Arguably, the former is the bigger problem.

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leatchr avatar image leatchr commented ·

Pretty sure they are in parallel. I'm in Australia with 240 standard power. Understand the discussion about the algorithm issues. I reached this thread via similar symptoms (PowerAssist kicking in well before shore power limit reached) but the underlying issue (in my case) was the DMC problem. Just sharing in case anyone else with the parallel setup isn't aware how the DMC current is translated into the device configuration.



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ben avatar image ben ♦ leatchr commented ·

I'm sorry, I misread your comment about "12/3000/120" to mean 12/3000 120V, but in fact the charging current happens to be the same as the North American voltage rating in the model numbers.

You are right, I retract my statement!

However, I still think the thing you are noting is a separate concern from the issue some are seeing with the load management behaving too conservatively. This happens with single inverters not subject to the confusion with applying a single current value to a stack of two units in parallel, and the mismatch is much larger in proportion.

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karl-thomson avatar image
karl-thomson answered ·

I had the same kind of issue after adding a bvm smart and then disabling the “enable battery monitor “ setting. I could only get about 39a charging from a 3000/24/70. I tried a generator feed, mains, and all those other settings weak ac and all that, once I enabled the battery monitor again it went to full power draw from ac in again.

My guess is that without the battery monitor enabled it doesn’t know the size of the battery perhaps?


system - multiplus 3000/24/70-16, bmv712, 250/100 mppt, colour control gx,

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tke577 avatar image
tke577 answered ·

I'm seeing this behavior as well and it makes the inverter boost mode completely useless. I'm sitting on 30 amp right now, oven on and with everything else pulling 11 amps. I turn on the air which pulls 12 amps for a total of 23 amps and the inverter starts spazzing out trying to help with a load that doesn't need any help. This setting is 100% useless for anything less than 15 amps and in reality likely less than that.

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twilson80 avatar image
twilson80 answered ·

Has there been any resolution to this problem? I am too experiencing this issue while plugged into shore power (15A outlet) the input limit set to 11A and trying to run my air conditioning. The most the Multiplus (12/2k/80) will pull is 850w and it's pulling the rest of the power from my battery bank. Super frustrating!

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dannyclark avatar image
dannyclark answered ·

Following with similar problem. Is there no way to get Victron to engage in earnest? Multiplus 12/3000/120

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paulbram avatar image
paulbram answered ·

Yet another +1. Has anybody contacted Victron? This seems like a pretty clear bug.

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william-brack avatar image william-brack commented ·
i'm seeing something similar with a multiplus compact.


running firmware v485, setting the current limit to 4A, and having a 3amp load.
but it'll sometimes only draw 2 amps from the AC input, and turn on power assist to supply the other 1amp instead of using passthrough + charging.

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pat-e avatar image pat-e william-brack commented ·
Same with Quatro 5K too.
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showtime3 avatar image
showtime3 answered ·

Still no answer for this? Was a problem when I bought my first Victron inverter 2 years ago. I'm about to order another Multiplus for the new build but this kind of bug is a big problem. Says a lot that they continue to ignore it. Especially for such an expensive unit.

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vr6mole avatar image
vr6mole answered ·

Exact issue is happening to me with my 24/3000. Very frustrating knowing the Honda 2200 will cover the AC load just fine with the multiplus out of the mix.

My workaround was to actually get a Westinghouse 4500 watt generator that I take with me when I’m going to very hot places. I just run the generator at 25 amps for about 2 hours a day and that allows me to completely run the AC as well as get some extra juice into the batteries.

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looknow12 avatar image
looknow12 answered ·

Same issue here. 15 amp limit. pulling only 1100 watts. Whats interesting is at first it will pull 1500 watts to match output of 1500 watts. But within 30m seconds or so it goes down.

There is no reason I should be pulling from the batteries.

Also and see attached example. The less the AC Output load, the higher the shore power.
Three screen shots, Initial showing how it can acommodate with the same wattage, 2nd how it derates the shore power, and third how it steps up when load is only 400 watts.snag-b22a98.pngsnag-b32dfe.png

low-ac-out.png


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afk314 avatar image
afk314 answered ·

Same issue for me. My 12/3000 will only pull about 1200w from the generator although there is plenty of capacity left. I'm glad to see this thread since it has been an issue for years and I am constantly trying to figure it out. Victron - can we get someone to do a deep dive with one of the people on this thread?

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charcast avatar image
charcast answered ·

I'm experiencing the exact same issue as described in this thread since April of 2019. Perhaps we can get Victron's attention if we start talking about a class action suit for the undue ware on our battery banks.

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svjubel avatar image
svjubel answered ·

How is there no response for this? Same issue - Generator only putting in 700-900W regardless of current limit or anything else.

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Jeff Jensen avatar image
Jeff Jensen answered ·

Glad I have not purchased my multi yet. May have to go magnum hybrid.

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Frank avatar image
Frank answered ·

I have sold many of your system and i have never seen that , but im going to try to

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damon-blumenstein avatar image
damon-blumenstein answered ·

I had same issue, this describes is perfectly and I see a lot of people are having the same issue. @mvader (Victron Energy) are you able to help here?


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corn18 avatar image
corn18 answered ·

I did some experimenting with this. I have an MPII 12/3000/2x120, Cerbo GX and I also have the Control GX. I like having quick access to the current limit, that is why I have the Control GX panel.

I have a Champion 2500 gas genset. It's really limited to 1800W continuous.

I had the genset running. I was running the residential fridge and one 15k A/C unit with soft start. Total load with A/C running and fridge compressor running is 1440W. My genset can handle that, but it will shut down if the A/C is running and the fridge compressor kicks in and vice versa. So I use the MPII power share to handle the surge.

In order to get the fridge and one 15k A/C to come on reliably, I have to set the Control GX current limit to 12A. Once both are on, and the current limit set to 12A, I am seeing 900W draw from the genset and 540W from the inverter. But I can now turn up the current limit on the Control GX and set the genset draw to whatever I want. I didn't take any data, but maybe I will. I can run it up to 16A limit and draw 1550W from the genset. That covers the AC loads (1440W) and leaves a little for charging the batteries. The nice thing is I can set it to whatever I want and get a response from the genset load. No dead bands and it seems linear, although I will need to collect more data. It's nothing like what everyone is describing here.

One thing I have not tried is letting the A/C turn off with the current limit knob set to 16A and then have the A/C turn back on. My guess is that will overload the genset, but will have to try it.

I also ran an experiment where I had the residential fridge running (compressor on) and both of my 15k BTU A/Cs on. This pulled 2681W. The genset was contributing 1704W and the inverter was supplying the rest (pulling 88A from my LiFePO4 batteries). I forget what I had the current limit knob on the Control GX panel. I could change the current limit with the Control GX panel and set the genset to any load I wanted. It was really precise.

So, is anyone else using the Control GX panel to set the current limit? I find it works very well and is highly adjustable and predictable.


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svjubel avatar image
svjubel answered ·

So I just tested this with shore power and not a generator and its the same thing. The shore power input into the boat for usage is limited to 1100W - Anything over that and it goes to assist mode. It doesnt make any sense. What is going on?

Why is victron not helping with this?!

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scott-guenther avatar image
scott-guenther answered ·

no info to add other than I have a MultiPlus-II 2x 120V and see the same issue. I specifically got this model to be able to run my ACs on a 15amp circuit if I had to. they pull on average of 13 amps. but with compressor start that goes way above that so I pop 15amp breakers.


I have reached out to 2 dealers and put in a support request from Victron but never heard back from anyone.


you can see with the low load it will pull 17 amps for charging. but still set at 17 amps if there is a bigger load it will use batteries even though it knows it can get it from the grid. this is a main selling feature and I have found people complaining for 3 years about it. Its basically worse than not having assistance at all.

I have run into the situation where it uses battery to run the AC's in assistance mode set at 17amps till the batteries die, then the whole unit turns off since the batteries are dead and I can't even use shore power.....this is crazy, I have to keep another battery charger around just to boost the batteries back over 10.5V so the inverter will turn on and charge and pass shore power.

screenshot-2022-07-15-19-08-40-41-30b6efbd53acd6f2.jpg screenshot-2022-07-15-19-09-14-92-30b6efbd53acd6f2.jpg


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corn18 avatar image
corn18 answered ·

Did some testing today. I did the testing with the Digital Multi Control enabled using the rotary knob to set the current limit and with it disabled and using the Cerbo GX display to set the current limit. There was no difference in how it worked.

I turned on the system and started the Champion 2500 and disabled Eco mode. Solar was turned off. I had the current limit set to 15A. I turned on the fridge and wated for the compressor to kick on and then turned on one 15K A/C with soft start. Data is listed as current limit:generator watts:battery amps:AC watts:power assist

W15A:1674W:0A:1654W:0W
14A:1251W:-40A:1715W:500W
13A:1262W:-40A:1715W:453W
12A:1262W:-40A:1734W:472W
11A:1192W:-48A:1754W:562W
10A:1084W:-60A:1780W:696W
9.5A:1021W:-65A:1776W:755W

Now I turned the current limit back up to 16A

16A:1276W:-40A:1743W:467W
17A:1276W:-40A:1741W:465W
18A: After a few seconds, the genset overloaded and disconnected

I reset the genset and fired the fridge and a/c up again to try again.

This time I set the current limit to 18A using the rotary knob. I waited for the genset to bog down and then reset the current limit to 15A. This resulted in the MPII not being in power assist and the genset providing 1712W to power the fridge and a/c. So I have discovered how to get the MPII out of assist mode. This is where it settled back in:

15A:1598W:6A:1513W:0W

I then turned on the microwave:

15A:1593W:-137A:3079W:1486W

I then turned off the microwave:

15A:1267W:-40A:1740W:473W

So, it remained in assist mode even though the genset could handle the load. I did the same thing and set the current limit to 18A, waited for the genset to bog down and reset the current limit to 15A and now the power assist was off again.

So, it seems the minimum power assist is around 500W. When it kicks in, it is going to draw 40A from the battery and never come out of assist.

One thing I did not try was turning off the a/c when just the fridge and a/c were on. That would drop the AC demand down to 200W. I would hope the MPII would come out of power assist then, but I will have to try it out.

Personally, I don't mind the 500W of assist. That takes my genset load from near 100% down to 67%. I think that is a better place for the genset to run vs. 100% all the time. Yup, it sucks 40A from the batteries, but I may be able to live with that because I have 1200W of solar to make up that 40A.

The next step will be to test this on shore power, which is the scenario that most people are complaining about. Will have to tow the camper home for that. Although my little genset simulates a 15A connection almost perfectly. Instead of popping a 15A breaker, it shuts down.

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svjubel avatar image
svjubel answered ·

See and no matter what I change or adjust, I can not get the inverter to pull more than 1100W from shore power or generator - Even on a 30 Amp shore plug. Its like its limiting shore power coming in somewhere for some reason, and my digital multi control knob being turned does absolutely nothing, even though i have the override setting on in veconfigure. I wish i could get 1700W in from my generator...

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corn18 avatar image corn18 commented ·
One thing I had to do when I disconnected my digital multi control panel was to go into the MPII menu on the Cerbo GX display and force it to redect the system. If I did not do this, I could not change the current limit via the Cerbo GX display. Then when I reconnected the multi control panel, I had to do another redect system to get the multi control knob to work again. The setting is under menu, MPII, advanced.
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corn18 avatar image
corn18 answered ·

Went back to the camper again. Same setup. Fridge and a/c on, 15A current limit. Genset provided all power (1700W). No assist. Turned on the microwave to drive the MPII into assist and then turned it back off. As expected, the MPII stayed in assist even though there was enough genset power to handle the load. Then I turned off the a/c. Went down to 200W load and the MPII came out of assist. Turned the a/c back on and the MPII did not go back into assist. Genset was again handling the entire 1700W load. That's good.

One more test I want to do is bring my heat gun out to the camper so I can adjust the load. Will force the MPII into assist with the heat gun and then reduce the load to see when exactly the MPII comes out of assist. Will be curious to see if it comes out of assist once the AC load is 500W less than the current limit (15A=1800W).

I have to say, the power assist behavior makes me happy. Yeah, you can get stuck in a zone where it is assisting when it doesn't need to, but I can fix that by turning something off and then back on again. Not sure why there is a 500W minimum power assist, but I think I can live with it.

What are people experiencing where this becomes a problem?

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damon-blumenstein avatar image damon-blumenstein commented ·
With my power assist going on even though I have my generator hooked up, I can only run the AC for about 12 hours with battery capacity (600ah). So that means if the sun is not out for 12 hours and I need AC in hot/humid conditions, I will have a nearly dead battery by the time the sun comes out, and 1500watts of solar is not going to be enough to charge that up to 100% in 1 day. THAT is a problem. If the generator supplied 2000 watts like it should, and the batteries just assist each time the compressor starts up and then hands power back of the the generator, I would have no issue. This was the scenario I was in a few weeks ago when I discovered my issue, thankfully, I was only boondocking over night and hit a camp ground the next day. I would be screwed if I needed a full day or 2 like this.
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corn18 avatar image corn18 damon-blumenstein commented ·

So the issue you are having is the genset needs assist to start the a/c and once the inverter is in assist, you are stuck there drawing power from the batteries? Even though the genset has enough power to run the a/c at that point without any assist?


I can get my 15k a/c with soft starte started without the MPII going into assist with my Champion 2500 (which is really 1800W). So I can start my a/c and run my residential fridge without getting stuck in assist. If I forget and turn on the microwave it will go into assist and then I will have to turn the a/c off and back on again to get out of assist.

If your genset isn’t big enough to start one a/c without assist, then that will get you stuck in assist and drain the batteries. That would suck, although some solar would help.

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damon-blumenstein avatar image damon-blumenstein corn18 commented ·
Thats the whole point to the assist feature as advertised. You can get a smaller generator and use the MP2 as a soft start. The generator can start the AC without the MP2 supposedly, but I wanted to prevent the huge flare and take advantage of the system.
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corn18 avatar image corn18 damon-blumenstein commented ·
Do you have a soft start installed?
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corn18 avatar image
corn18 answered ·

More data. This is interesting. Today I left the fridge off to control the demand better. Took a lot of measurements.

Loads of each appliance I used:

Rear a/c: 1437W

Front a/c: 1301W (not sure why it is less than rear a/c, they are the exact same Coleman Mach 15k with soft start installed). This comes into play later.

Microwave: 1176W

Heat gun on high: 1275W (the heat gun has a thermostat and can't be used very well as a variable load).

I had the genset running not in eco mode and the current limit set to 15A for all tests

First test was with the heat gun and microwave:

Heat gun + micro = assist Turn off heat gun = no assist

Heat gun + micro = assist Turn off micro = no assist

This is interesting because it seems to come out of assist with a 1275W load

-----------------------------------------

Rear a/c only = no assist

Rear a/c + heat gun = assist

Turn off heat gun = assist

So, the 1437W load of the rear a/c keeps it in assist

-----------------------------------------

Rear a/c only = no assist

Rear a/c + heat gun = assist

Turn off rear a/c = no assist

Ok, now we are getting data. Seems that the assist will turn off after it is on if the load is 1275W but not if the load is 1437W. Interesting.

-----------------------------------------

I decided to try out the front a/c to see what happens.

Front a/c only = no assist

Front a/c + microwave = assist

Turn off microwave = no assist

Hmmmmm.... The front a/c draw of 1301W allowed the MPII to come out of assist. This is different than the rear a/c draw of 1437W. So the threshold for coming out of assist once in it is somewhere between 1301W and 1437W. Since the max the MPII would draw from the genset is 1600W with the current limit set at 15A, I am going to draw a conclusion that dropping the load down to 1300W after going into assist will get the MPII out of assist. Maybe it's a little lower than that, but I didn't have the load management available to adjust that precisely.

So the minimum assist seems to be around 500W from my previous tests. To get it out of assist, the load needs to drop below 300W below the max that the current set limit will allow.

Above 1600W load, MPII goes into current assist and provides a minimum of 500W

The MPII will stay in assist made until the load drops below 1300W

Hope this makes sense.

-----------------------------------------

I decided to see what happens using both a/c.

Both a/c on = assist

Turn off front a/c = assist

Both a/c on = assist

Turn off rear a/c = no assist

Same result as above. The rear a/c draw of 1437W keeps the MPII in assist while the front a/c draw of 1301W let's it come out of assist.

-----------------------------------------

Not sure this helps anyone, but it is good data.


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johanndo avatar image
johanndo answered ·

Power factor setting affects this behavior. You don't want to trip the shore fuse, so Victron stays below the limit, also gives some lee way for kicking in loads. Main objective is to protect the mains connection from tripping, while using shore power as good as it gets.

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afk314 avatar image
afk314 answered ·

As others have stated, I know my 2200eu propane genset can't handle my AC in the summer. Or at least not above 5000'. What I want to do is pull 90% from it and let my batteries handle the rest. As it stands, I get into a significant battery deficit now since the genset can only provide ~1100w. After running the AC for four hours, I need to run it another after things cool off just to replenish. Super annoying and I am hoping that next year there is some new firmware that helps me use less battery power! It's all I want for Christmas, Santa. Can you make it so??

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mtrethewey avatar image
mtrethewey answered ·

Hey all,

Back on this, mine is doing this now after the last update.

I have my limiter set at 30 amps, and it pulls hard off the battery not going over 12 amps from shore.

batt.png

amperage.png



batt.png (16.7 KiB)
amperage.png (18.1 KiB)
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darrelh avatar image
darrelh answered ·

I accidentally ran across this post while looking for how/where to adjust the current limit. Glad I did, because we were about to sell our 4500w generator to get a smaller/lighter 2500w (1650 running watts on propane), and this thread makes my head spin.


So @mtrethewey you're confirming that on latest firmware, it's still not functioning as we wish it would, right? Such a bummer.

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pat-e avatar image
pat-e answered ·

August 2023 and nothing has changed from above.

Power Assist is still "Battery killer 2.0"

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jeff925 avatar image
jeff925 answered ·

Feb 2024 and I'm still having this issue. My well pump draws about 1200W and it will kick the Multiplus II into Power Assist if the generator is running (Honda 2200). The well pump runs fine on the inverter if the generator is not running and it runs fine on the generator without the inverter. The combination of the two is really that: "Battery Killer 2.0". More of an issue in the summer if I'm watering for a long time or running AC.

Just to note, my well pump is running off a VFD so there is no starting surge. 120V single phase input, 208V 3phase output.

I guess the solution is a bigger generator or more solar. Both will happen eventually but it would be nice to see this work correctly.

@Johannes Boonstra (Victron Energy Staff) do you have any plans to address this? There seems to be quite a few people who are experiencing this. I just want to draw 15 amps from the generator all the time, no matter the load. If power assist has a minimum operating power, that's fine, as long as it doesn't kick in before the input current limit is reached.

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JohnC avatar image JohnC ♦ commented ·

@jeff925

"If power assist has a minimum operating power".

Indeed it does, and is specified for individual models. So when your 15A limit is reached it has to at least apply that. Overlooking any safety margins, once you hit 15.1A and PA starts, it will apply that minimum (let's say yours is 3A), and only 12.1A will be then be drawn from the genset.

The 120V models have generally higher minimums than the 230V ones, and I'm sure Victron are well aware of the technical limitations of 'fixing' this. It may never happen.

The PA lower limits of particular units are available in an Excel file called 'Minimum Input Current Limits' from the Victron Professional website.

A downside to undersizing ac supply..


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jeff925 avatar image jeff925 JohnC ♦ commented ·
Yes, I am aware of that and I'm fine with the power assist minimums. What I'm not fine with is that it kicks in with a 10A load instead of a 15A load. My well pump draws 1200W which at 120V is 10A. Sure, there's some weird stuff happening inside a VFD which might make the load look different to the inverter but I'm nowhere near the 15A cutoff that I set for the input current limit. This also happens with other load combinations, not just the VFD.
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JohnC avatar image JohnC ♦ jeff925 commented ·
@jeff925

Output Watts is a long way from Input Amps. This is ac. Input A is what you look at, and if you're not happy with the 'safety margin', just raise the setting to compensate..

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