question

energy avatar image
energy asked

Multiplus-II 8kVA and 10kVA in parallel

I believe the 8kVA and 10kVA Multiplus-II's cannot be paralleled. Will this be fixed with a future software upgrade or never?

If it will be possible in future, then when?

Multiplus-IIbattery chargingmultiplus in parallelmultipus
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5 Answers
wkirby avatar image
wkirby answered ·

The hardware is different, so there is no kind of firmware that can change that.

Units must be the same hardware before they can be parallel or multiphase connected.

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ponzoa avatar image
ponzoa answered ·

yes, but, for me the question still stands. Will we be able to parallel two Multiplus II 8KVA together or two 10KVA units togetehr. Today, on paper at least, it's not possible, right?

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wkirby avatar image
wkirby answered ·

Oh, apologies. I understand the question now. Those ones will not be able to be paralleled yet, due to hardware limitations.

Maybe future hardware versions will be able to, and then, a firmware update may or may not enable the existing hardware versions.

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rainer avatar image
rainer answered ·

To be able to extend the setup, maybe it is better to have two Multiplus II 5 kVA in parallel, rather than one Multiplus II 10 kVA?

What are advantages and disadvantages of having one Multiplus II 10 KVA vs. two Multiplus II 5 kVA? Let me try to summarize my view:

Criterion
1 x Multiplus II 10 kVA
2 x Multiplus II 5 kVA
Extensible with additional units
no
yes
Space requirements
less
more
Cabling requirements
less
more
Price
slightly more expensive
slightly cheaper
GX unit
separate
can be included in one of the devices


Is there anything else that I may be missing in the comparison? What about noise, reliability, ease of setup, etc.?

7 comments
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marekp avatar image marekp commented ·

@Rainer

When you have a parallel system you can have error#17 or #18 stop your system cold and hard reset is required.

I have error#18 happen once a month and there is no way to find a reason for it.

It is so frustrating and I am happy to soon change my 6x MP-II/3k into 3 MP-II/5k.

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nickdb avatar image nickdb ♦ commented ·

Our parallel setups work fine, just stick to the victron compatibility guides and best practices and it works well. It's only those who go DIY or have science projects that seem to hit errors.

The benefit of 2 x 5, is that if one dies, you can at least run at half power still.

Another negative, the idle load will be a bit higher with multiple units, but in the big picture that doesn't matter.

It is a bit more complex to setup though.

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marekp avatar image marekp nickdb ♦ commented ·

@nickdb

Our parallel setups work fine, just stick to the victron compatibility guides and best practices and it works well. It's only those who go DIY or have science projects that seem to hit errors.

I would understand this statement if you were the sole Victron installer in the World and all installation not done by you where DIY. I would suggest a bit of modesty.

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nickdb avatar image nickdb ♦ marekp commented ·
Creating the impression that all installs will have those errors is disingenuous.

It may be common on your install but you have made specific choices which are off-piste.

So sure, errors can happen, but on the whole, parallel installs work fine and ongoing issues have less to do with the product and more with the install/installer.

Except everyone blames the manufacturer when they choose the road less travelled.

I choose taking responsibility over modesty any day.


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marekp avatar image marekp nickdb ♦ commented ·

@nickdb

Show me where I claim that "all installs will have those errors"? Your claim that I do is disingenuous, as well as your claim that only DIY systems have those errors.

Can you explain what are the "off-piste" choices?

I had a bunch of problems with my parallel system and it is not DIY parallel system. I payed Victron installer to do it but when problems started he vanished leaving me with the problem.

I would not say anything bad on the manufacturer since thanks to their help and commitment my system works and soon will work even better as non parallel one.

Just for you to know, my problems where related to the product itself.

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Merle.Peter avatar image Merle.Peter nickdb ♦ commented ·
My understanding is that if two multi's are in parallel and one fails , the other will shutdown and you have no power output. Can someone from Victron confirm this .


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marekp avatar image marekp Merle.Peter commented ·

@merle.peter@gmail.com

Your understanding is correct.

When one fails you can reconfigure for single inverter and resume this way with a half power.

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energy avatar image
energy answered ·

I want to build a 3 phase system with about 20 kVA per phase over time. Can the 8 and 10 kVA parallel? The other features and functionality fades into insignificance. It was simple question. Let's not make rocket science out of it.

1 comment
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
No, at the moment it is not possible.

If it will be possible with the current hardware and a firmware update or if it needs a new hardware revision is not sure at the moment.

If you need 8 or 10 or more kVA per phase you should use the "old" MultiPlus or Quattro (+ external NA protection).

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