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max78 avatar image
max78 asked

Multiplus II Power Temperature

I have a Multiplus II (3000) and it works very well.

But I was wondering why the MPPT reduces power so often.

Unfortunately, I did not find any value for the currently generated power (and internal temperature). But I calculated the power.

Are this both values readable?

In doing so, I came to the conclusion that the inverter does not specify the 2400W as in the data sheet, but only delivers 1700-2000W.

I'm not allowed to use the 5000 because of one phase operation.

I then rsomeone told me that the temperature in the data sheet is not the ambient temperature as usual, but the internal temperature. How are you supposed to come up with something like that? Is somehow already very cheeky from the manufacturer.

I have already recommended the Multiplus II to a number of people, but will not do so again in the future.

Because naming the inverter 3000, then specifying continuous output as 2400W and then in reality not even making 2000W, is not worthy of a premium manufacturer.

The other manufacturers specify 3000W and then deliver it constantly!

Multiplus-IItemperature
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Alexandra avatar image
Alexandra answered ·

@max78

Other manufacturers deliver 3000W constantly. Ok. Also longevity would be an issue so there a trade off, not that it is a good one. (Six month warranty vs 5 year extendable to 10)

The limitation is actually electrical components (they have operating ranges) not Victron, they just set up to increase lifespan of units.

With a cerbo you can add temperature sensors, monitoring sorted.

If you are really serious about power production then environment controls are added to the installation as well. Or you use a bigger unit to compensate for derating.

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max78 avatar image
max78 answered ·

The Longevity is really great and important. But other premium manufactures have 5+ years warranty. With reduced power maybe over 40 or 60°C room temperature.

If better components are used (lower Resistance Mosfets…) or/and better cooling (bigger fans) it would work much better.

But I don’t think I get warranty if I change this?

I have never seen a device rated like this. (this can’t be seen in the data sheets)

Usually it is designed for different room temperatures.

Below 20°C room temperature, it should never reduce the output power.

I’m only allowed to use a 3000W inverter. So I can’t us a bigger Multiplus. It does not matter if it has 3000W for long or short time.

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Alexandra avatar image Alexandra ♦ commented ·
I am also going to say construcion of the units. The Victron has a transformer, which has its merits and disadvantges.


Are you now comparing them to units that are without and have a completly different constructionnas in no transformer base.

Efficiency and power factor are something to consider in systen sizing and design. Details that are often overlooked with lack of experience and lack of more expert knowledge.

If you are unhappy with your systen performance the people who specified and installed the system for you are the ones to take issue with. They did not consider your needs in its entirety.

Why is the restriction 3kva?

That is interesting as the Victron can be programmed for smaller input current connections so you can use bigger power with the power assist feature of the inverter and the restructed input current?

I have some 15kVas in the field that are on a restricted 16A connection for that very reason.

The 3kVa is lower wattage... VA is only the same a Watts when Power Factor is 1:1. And it invariably never is on loads side or in the inverter.

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Dušan Klofutar avatar image
Dušan Klofutar answered ·

3000VA = 2400W because power factor is 0,8...

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tazer avatar image
tazer answered ·

I am facing the same issue, I have 3 Multiplus II 48/3000, they should be able to continuously supply 7200W of Power. They do, but only for a few minutes, before the internal temperature gets too high and they reduce their output to about 1900W each (~5700W total).

I get around 8000W PV power and planned to charge my EVs at 7.2kW (or feed into the grid), but with the reduced output I'm constantly losing 1.5kW on sunny days. I have batteries, but they are almost always full during summer.

I wrote an email to my reseller and asked if it would be possible to upgrade to the 48/5000 type, which would likely sort my problem, but I too find it a bit strange to advertise 2400W continuous and deliver 1900W. My inverters are in a cold basement, around 16°C ambient, unrestricted airflow, now imagine how bad that gets in a van or on a boat.

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max78 avatar image
max78 answered ·

Is it possible to set 3000VA = 3000W with an other power factor (maybe 1)

Maybe diffrent for on and off grid?

A lot of inverters have 3000VA=3000W

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Alexandra avatar image Alexandra ♦ commented ·

A lot of inverters say they have 1:1.

I have yet to used or install one that is so. But then I have not installed every brand in existence.

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paul-campbell avatar image
paul-campbell answered ·

3000VA == 3000W with a purely (fictional) resistive load, a power factor of 1.0 and a perfectly efficient "ideal" transformer.

The finger in the air VA->W is usually taken as 1.4:1.

For real world values.... My inverter load is currently 85W. The inverter "rating" nuemonic 'S' is 150VA. As reported by the inverter. Giving me a power factor of not more more than 0.5!


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paul-campbell answered ·

My personal irritation in this is the fact the inverter IS rated on it's internal temperature AND it does not come with a temperature monitor built into it.

The fact victron wants me to pay for that makes me literally want to spit at their feet, rotate on my heels and never buy a single product from them again. It's 1 too many add-ons. 1 too many.

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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

Multiplus-II GX Online Manual

MultiPlus-II 230V Datasheet 

VE.Bus Error codes

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