question

francesco-marzulli avatar image
francesco-marzulli asked

Which generators are fully compatible?

I want to build a photovoltaic system for my home similar to the following (I will probably use EasySolar II instead of Multiplus II+SmartSolar MPPT+CCGX):

https://www.victronenergy.com/live/_media/battery_compatibility:ds_-_pylontech_-_managed_lithium_battery_-_2021-3-11.jpg?w=800&tok=2a5c8a

Which generators are fully compatible?
Someone has already used the Black & Decker BXGND5300E and / or BXGND6300E?
Someone has already used PRAMAC PMD5000s ?
I want to use the generator only for the time necessary to recharge the battery (2-5 hours) when the public grid is not available and solar energy is insufficient (I could also disconnect all non-essential domestic loads, if necessary to facilitate the operation)
I believe it is important that Victron publish a list of fully compatible generators for this type of application, without delegating the responsibility to local dealers.


Generator
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5 Answers
Alexandra avatar image
Alexandra answered ·

@Francesco Marzulli

Define fully compatible?

Will the inverter synchronize ( in most cases yes if it has a good AVR in it?

Can it be remote started? Is that a feature you want or need?

There are different types of generator, so you need to look at what is available locally for you, andthen narrow down the list with the requirements for your specific system Or chat to your nearest Victron Dealer, which I see you do mention.

The list of generators that work is long and would be a ridiculous task to undertake, I think. I personally have never installed the same generator on two different sites, once you know the basic settings then almost any generator works.

This article explains more including sizing for the inverter you are wanting to buy.

There are a few threads on the forum that discuss the topic a bit, like this one.

https://www.victronenergy.com/blog/2017/11/27/the-trouble-with-generators/

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
Depending on the country he live in (Italy?) and the local laws/gird code requirements it also highly possible that no generator is accepted at the AC input (with ESS programming).
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francesco-marzulli avatar image francesco-marzulli Matthias Lange - DE ♦ commented ·

Yes, I live in Italy... I still haven't been able to figure out some questions (I was unable to get clear answers from the local dealers I contacted):

1) What does it mean "good AVR" for correct synchronization generator/inverter-charger? What about voltage and frequency tolerances? What about THD?

2) Can I use in Italy generator with ESS system to recharge the battery (within 2-5 hours) when the public grid is not available and solar energy is insufficient? [it will be necessary a manual switch (between grid and generator) in Multiplus or automatic switch (between 2 AC input) in Quattro]


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ francesco-marzulli commented ·
2.) I don't know the gird code for Italy or the local laws, you should ask a local electrician about that.

With the German grid code (needed for ESS) you won't be able to use a generator at the input.

You have to use the new Quattro-II for that.

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francesco-marzulli avatar image francesco-marzulli Matthias Lange - DE ♦ commented ·

Thanks, Matthias. I hope to get more details from some Italian retailers as soon as possible, perhaps directly in this community, aboute ESS situation in Italy.

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kevgermany avatar image kevgermany ♦♦ francesco-marzulli commented ·
1) AVR is Automatic Voltage Regulator. Controls the output of the generator. Basic ones simply control voltage and allow frequency to float depending on engine speed. What @Alexandra is saying that higher spec ones take care of your concerns.
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francesco-marzulli avatar image francesco-marzulli kevgermany ♦♦ commented ·

Thanks, I already know the meaning of AVR, ATS, THD... my doubts are others.

For example: for the BLACK + DECKER BXGNP6510E generator (6.5Kw-230V), I found that AVR = 1.5% (https://groupe-elec.com/de-6000-a-12000-watts/2399-blackdecker-groupe-electrogene-65kw-essence-230v-bxgnp6510e-8435528157998.html) and it seems like a good value (I have read that generally AVR = 5% for most generators): is this enough to be sure that I will have no problem with both Multiplus and Quattro to recharge the batteries, when it is not available local grid? Should the THD value also be checked? If household loads are constant while recharging the batteries, could there be other problems?

In other words, can I be sure that I can successfully use this generator in Italy for the ESS system I am dealing with? (https://www.victronenergy.com/live/_media/battery_compatibility:ds_-_pylontech_-_managed_lithium_battery_-_2021-3-11.jpg?w=800&tok=2a5c8a)

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kevgermany avatar image kevgermany ♦♦ francesco-marzulli commented ·
Sorry, no idea.
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klim8skeptic avatar image klim8skeptic ♦ francesco-marzulli commented ·

I found that AVR = 1.5%

What does this figure actually mean?

Looks like generic chinese export..

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francesco-marzulli avatar image francesco-marzulli klim8skeptic ♦ commented ·

It is the maximum variation of the voltage regulator ... therefore:
230V ± 1.5%
50Hz ± 1.5%

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klim8skeptic avatar image klim8skeptic ♦ francesco-marzulli commented ·

230V ± 1.5%

50Hz ± 1.5%

That is what I would have thought.

However this is not achievable with an AVR.


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JohnC avatar image
JohnC answered ·

Hi @Francesco Marzulli

Victron have looked into this, at least with some gensets. Their report is from quite a while back, but has aged gracefully. It may explain a bit to you about the different types (not necessarily brands) and how they perform.. https://www.victronenergy.com/upload/documents/VE_Marine_generator_test_RVA_07-jan-2008.pdf

I've used a few different types myself, and find their experiences close to mine. And what's available to me may be far different to your area. But I won't touch anything not genuine AVR or inverter regulated, and anything from China won't make my shopping list. Still a bit of a lucky dip though, a good brand your best chance of getting something useful. Choose carefully..

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francesco-marzulli avatar image
francesco-marzulli answered ·

I try to formulate the question differently.
Who has a photovoltaic system with storage battery for the home + emergency generator (in case of grid blackout or with an off-grid system) could indicate the model of the generator used with Multiplus II or Quattro?

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marekp avatar image marekp commented ·
@Francesco Marzulli

I have PV system and it runs ESS assistant.

I have a generator that charges my battery directly.

For now it is a very crude charging system that consists of a regulated auto transformer, rectifier, power resistor and relay.

I use it only in emergencies and only for bulk charging.

Eventually I will buy or construct a proper LFP charger for use with my generator.


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markus avatar image
markus answered ·

Hi @Francesco Marzulli

maybe I can give you some helpful tips here.

First of all, it makes a difference, if you are going to use ESS or not.

Depending on that, you will have to set your Multis/Quattros to follow a grid code, or not - this makes a big difference.

Speaking generally, there is a big difference in AC quality, that comes from the grid, compared to AC output of a genset.

It depends on the type of generator what to expect in general:

Eg.:

Capacitor regulated: cheapest method, stable and longliving technology, not the best AC output stability.

AVR: less cheap in general, cheap regulators die easily, pretty stable and good quality AC output, better overload capabilities.

Inverter: complicated electronics, best AC output quality, engine speed is variable to output power, bad overload capability, smaller type of gensets.

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important VE.configure settings for generators:

1645184954025.png

Most important setting: AC input current limit. This sets the maximum current draw from that source. This limits the power the genset is loaded with. (There is an excel sheet around for minimum values for different units, to retain power-assist functionality)

Dynamic current limiter: this option prevents that the genset is fully loaded at once. This setting raises the draw from the input step by step, so the generator has some time to regulate

1645185000592.png

Accept wide freq. input. does exactly what it says. Useful, if the genset is not stable 50Hz.

UPS function: disable this to make the input less sensitive, for a slightly longer transfer time.

This option is recommended to be disabled on most gensets. Only the really good ones can handle UPS setting staying active.

1645185033780.png

Weak AC - input. It basically reduces power factor of the charger part, and uses another mechanism, to be able to operate with weaker AC sources. In my expierience, it is with most gensets, not neccessary to enable that.

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With these settings, I was able to operate most generators with all 3 regulation methods mentioned above at the input of a Multi.

Even cheap €250 ones from the toolstore, operate good and reliably. But performed far away from the full advertised power.

I found out, most cheaper Gensets are only able to operate continuously at maybe 60-70% of their rated power some even lower, if you use them for longer, expensive ones will most likely work at their rated COP.

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1.) No grid code set. No ESS system:

You are happy to use all options above, most gensets will work

2.) Grid code set, ESS system with Multis

Your single input is configured to follow strict grid rules. Most options are not available, Multi will export energy to input - no genset on input possible

3.) Grid code set, ESS with Quattros

Well this situation is a bit odd, if you set a grid code on a Quattro, both inputs follow the grid rules in terms of V and f. Export is disabled for the input that is set to generator in Venus - system settings. It is only possible to disable LOM on the generator input, no V and f settings are available.

Only real HQ AC output gensets are going to work on the generator input. I would not advise to go this way. There might be a possibility in future firmwares to be able to except the generator input from the grid rules - but not at this time. Additionally - you have to take care, if you have AC-PV on AC-output. The Quattros freq. shift is not going to work if the genset is accepted on Ac-in.

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Another downside with generators operating at the AC-input is, that the network type plays an important role. Most smaller gensets are isolated IT type gensets. It is not legally allowed to use them at a house installation by most local laws. You have to use a genset equipped with RCD, those are not the entry level price ones.

If a genset gets accepted on AC-in of a Multi or Quattro, the AC-output is bond to the AC-input. This means you will most propably have flickering lights and poor AC quality in your circuits, when you use lower level gensets.

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Conclusion and solution:

In my opinion, the best and eaysiest way to implement a genset in a ESS is, to DC couple the genset to the battery via an extra charger. This could be another Multi connected via a MK3 interface (for an extra VE.bus port) to the GX, or any other charger you want.

If you go this way, you will have all options available to setup your generator and most gensets are going to work. The network type of the genset doesn't play an important role, you don't have weak generator AC inside your circuits and it is also possible, to blackstart the system if you only have AC-PV and your system is missing MPPTs.

Downside of this method is the efficiency loss, if loads are consuming AC directly when the genset is running.

Don't forget to implement safety, via Allow To Charge contact when using a Lithium battery.


Hope my few cents are going to be somewhat helpful.

Have a good time.


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markus avatar image markus ♦♦ commented ·

PS.: I personally use a Pramac P4500 diesel genset and I am quite satisfied with it. It doesn't work on a Quattro2 Ac-In when AT TOR Erzeuger grid code is set, but I use it DC-coupled to my ESS, via an extra battery charger.

When no grid code is set, this generator does work good on AC-In too.

The P4500 is maybe close to the PRAMAC PMD5000s you have mentioned.

BR

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jan-rotermund avatar image jan-rotermund markus ♦♦ commented ·
Hi, how do you start the Pramac - i'm in a similar project an have a Pramac ES12000 with the automatic grid switch - i'dont get it where to switch it on and off. Thanks!
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mikeb-1 avatar image mikeb-1 markus ♦♦ commented ·
@Markus Which extra battery charger did you choose?

best regards

Michael

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markus avatar image markus ♦♦ mikeb-1 commented ·
Hi Mike,


I use just another Multiplus as a charger.

This will be an independent VE.bus System, to connect that to the GX you can use a MK3 interface.

A MK3 interface connected to the GX gives you a VE.bus connection for an independent system.


Be aware that no DVCC or CANbus BMS control will work on that second VE.bus. You have to switch the Multi on via Allow to charge signal from BMS.


BR

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francesco-marzulli avatar image francesco-marzulli commented ·

Hi @Markus , thank you very much for your very detailed answer.

Based on what I have known so far, in Italy I will unfortunately only be able to build an off-grid PV system with battery, so I will have to use Multiplus II + generator and your information is really useful.

It seems, in fact, that both the Multiplus II and the Quattro cannot be connected to the public grid (so... bye, bye for my ESS), as they do not meet the CEI 0-21 regulations: can anyone else confirm this for me?

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markus avatar image markus ♦♦ francesco-marzulli commented ·

You are welcome.

Take a look at the Anti-Islanding Box 63A single and three phase - Victron Energy

Ziehl SPI1021:

Certificate: CEI 0-21 (Italy).


See attached PDF anti-islanding-solutions-en.pdf

Ask your electricity provider, if he is fine with your ESS, when you are going to use such a certified box.

BR

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francesco-marzulli avatar image francesco-marzulli markus ♦♦ commented ·

Thanks @Markus. However, it is very strange that the Multiplus has the CEI 0-21 certification, while Multiplus II and Quattro do not... even if the problem were solved with the Ziehl SPI1021, there would still be an additional cost and it doesn't seem very logical to me

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markus avatar image markus ♦♦ francesco-marzulli commented ·

Hi @Francesco Marzulli

I would strongly suggest, to talk to a local Victron distributor in Italy.

They should perfectly know what is possible in Italy and how.

Where to buy - Victron Energy


If this doesn't bring you further, you could try to contact the local Victron salesmanager.

See here: Contact - Victron Energy

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bhi avatar image bhi commented ·
Hi Markus, thank you ! This is the first explanation I've read, which describes the situation of a Genset on AC-IN correctly. I can follow your statements and also your recommendations !

So I will stop all further investigations to connect my generator (3-phase, 7kVA) to a Multiplus II (3-phase) system.

It makes really more sense to use a DC-Battery charger and load the batteries this way.

My generator has 1-phase power also and delivers about 5 kW for some hours.

What charger would you recommend ? Are there any reliable outside the victron world ?

Is a 4th Multiplus II a solution ?


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marekp avatar image
marekp answered ·

@Francesco Marzulli

You can use any generator and external battery charger and charge battery directly from generator.

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markus avatar image markus ♦♦ commented ·

It is generally what I said, using more words and background.

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marekp avatar image marekp markus ♦♦ commented ·

Sorry @Markus, I should have read all answer before writing mine.


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francesco-marzulli avatar image francesco-marzulli commented ·

Ok, @MarekP , but in this way, it is not easy to automate the charging process.

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marekp avatar image marekp francesco-marzulli commented ·

@Francesco Marzulli

Why not?

GX has no problem turning the generator on at set SOC (assuming it is auto-start type) and off when charging is done.

https://www.victronenergy.com/media/pg/CCGX/en/gx---generator-auto-start-stop.html

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francesco-marzulli avatar image francesco-marzulli marekp commented ·
Thanks, @MarekP .
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