question

blackstar avatar image
blackstar asked

GX or not GX

I'm planning to install a new system with a multiplus-II 5000 but I think that power will be not enough within some time (in a 2 years time frame). I'm planning to pass to a parallel configuration in two years. I will be able to add additional PV modules and batteries (Pylontech) and use more power and also to have a level of redundancy

Considering that is possible to have only a GX device what do you think is the better option:

1. Install now a multiplus-II GX now and then install a second multiplus-II GX, disabling the GX part

2. Install now a Multiplus-II and a Cerbu GX and the install another Multiplus-II

3. Install now a Multiplus-II GX and then, in parallel a Multiplus-II NO-GX

4. Redundancy is not required, use a Multiplus 8k or 10k now and a Cerbu GX and upgrade only batteries and PV modules

Thanks!

Kind Regards!

Danilo

multiplus in parallelgx device
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5 Answers
marekp avatar image
marekp answered ·

@blackstar

Based on my experience with the parallel system I would not advise to go with options 1-3 if there is time difference between first and second unit. Especially if its more than 1 year.

If you want a parallel system then buy both units at the same time.

Also I suggest to have separate GX unit (for example Cerbo).

If you can afford it, single 10k unit would be my suggestion.

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chrichri avatar image
chrichri answered ·

Never a GX if you would like to extend later on. With external Cerbo you are much more flexible, have more options ans if you add it, a great on site display for quick reaction and monitoring.

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Jason - UK avatar image
Jason - UK answered ·

I have a Multiplus II 5kva 48v GX unit and i do feel inwould have been better of having a non GX unit. My reason for going for the GX over the non GX was because i wanted a tidy installation but it is becoming problematic not having sufficient connection points for all the ancillary items. If i had a non GX Multiplus and a cerbo GX, i would not have some of the complicated setting up i now have with trying to make all my controls work. Its not impossible but ive had a hard time.

0e1292c1-58e7-4361-8bed-c1f8b739b187.jpeg

This photo doesnt show the final arrangement as i now have every AUx, K connection and the NC/NO relay ised with no spare capacity to add further controls.


0e1292c1-58e7-4361-8bed-c1f8b739b187.jpeg (2.8 MiB)
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nickdb avatar image
nickdb answered ·

Internal GX's have limited connectivity, a cerbo is a much better idea. There is no real difference in cost between a multi/gx combo and buying them individually. Individually you have much better options for expanding down the road.

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Jason - UK avatar image Jason - UK commented ·
I agree with that. When I was looking at both options, Non-GX with Cerbo GX was the same price as a Multiplus GX version and I'm regretting not having the additional connectivity.
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samson70 avatar image samson70 Jason - UK commented ·
So just to ask, as I am getting to see the wood from the trees. If I have a cerbo GX then getting a multi-plus GX is pointless. I could just get a multi-plus and the cerbo GX would do all the work with my smart solar MPPT and battery stack.



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samson70 avatar image samson70 commented ·

So just to ask, as I am getting to see the wood from the trees. If I have a cerbo GX then getting a multi-plus GX is pointless. I could just get a multi-plus and the cerbo GX would do all the work with my smart solar MPPT and battery stack.

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Jason - UK avatar image Jason - UK samson70 commented ·
@Samson70 you can only have 1 GX device in a system therefore by having a Cerbo GX, you cant have a Multiplus GX, you can only have the non-GX version of the Multiplus.
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kevgermany avatar image kevgermany ♦♦ Jason - UK commented ·
@Samson70

If you cannot get a non-GX multiplus, or decide to upgrade to a Cerbo from a multiplus with built in GX, the built in GX can be disconnected.

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petajoule avatar image
petajoule answered ·

I second many of the suggestions here, and differ in some.

  • go for the no-GX and use an external GX device (should be a Cerbo)
  • yes, you can attach another no-GX device in parallel in one year or so

No, you do not need to buy them at the same time, no it's not your problem if then there would be problems in a parallel configuration. It would be Victron's problem.

Yes, a 10kVA device would be more efficient (space, losses, money) but also less resilient than 2 x 5kVA. By the way, that's another reason why you would like to have both as no-GX, they are more interchangeable if one goes kaboom - and that happens from time to time.


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marekp avatar image marekp commented ·
@PetaJoule

It is a Victron problem only if you ask Victron, before buying, whether the new unit can work in parallel with the one you have and they say YES.

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kevgermany avatar image kevgermany ♦♦ commented ·
Always check with Victron before adding a second unit. They have documentation on compatibility.

If there's a significant time delay before adding a second multi, there's a good chance of compatibility issues.

Better to buy both at the same time.


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