question

kevin88252 avatar image
kevin88252 asked

Multiplus 2 2x5000 vs 1x10000

Hello Guys
i need some advice for doing a decision. i have found out that the 5kVA Multiplus II are way less expensive than the 10kVA. Does it have any dissadvantage to buy 6x 5kVA over 3x 10 kVA (3 Phase application)

i see one big benefit in buying the 5kVA, in case my energy needs will raise in the future i can add more Inverters in parallel, this is not possible with the 10kVA right?


thanks

Multiplus-II
1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

kevgermany avatar image kevgermany ♦♦ commented ·

Adding more in parallel depends on matching the internal hardware revisions. It might not be possible if you leave it too long.

1 Like 1 ·
2 Answers
manta avatar image
manta answered ·

If you got enough room, getting 5kva will save some money, but also is less efficient, more parasitic power draw. You can also look for a 8kva model.

5 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

manta avatar image manta commented ·
But using 5kva multiplus, the max power is a bit higher in general. Also you could make something on a Cerbo GX, node red for example to stop 3 of the multiplussen when consuming low power via the remote switch connected to one of the Cerbo relays, even in software (node-red) this is possible with the VenusOS large image.
0 Likes 0 ·
derrick thomas avatar image derrick thomas manta commented ·
You cannot switch off parallel multi's in a parallel/3 phase configuration. If one of the parallel units is switched off the master will shut down as well.
1 Like 1 ·
tyler-pomerhn avatar image tyler-pomerhn derrick thomas commented ·
Just curious - you say specifically if they are “switched off” - one of the reasons I was considering doing six 5k multis instead of three 10k Quattros was redundancy. So while intentional power off of a three phase parallel multi will shut all on that phase down, got it… but if one fails on its own, does the whole phase die? Also, does it matter in a failure situation if the failed unit was master or secondary?
0 Likes 0 ·
Alexandra avatar image Alexandra ♦ tyler-pomerhn commented ·
@Tyler Pomerhn

The whole system will shut down if one inverter dies.

It is better to have one in a box for a quick swap out if it dies.

Or look at the Multi RS range, they have the option to work if one inverter is off.

1 Like 1 ·
tyler-pomerhn avatar image tyler-pomerhn Alexandra ♦ commented ·
Gotcha. Thanks for confirming, it's not that 2x5k is "bad" but at least now I know that the argument "for" it (redundancy, if one fails you still work just at 50% capacity) is not valid. The other arguments for it (lower overall power consumption, easier cabling/fusing) and against it (more points of failure, more complicated install, potential for imperfect load sharing, etc) still stand.


As for other model(s), unfortunately in my use case (US-style power @120V, with the setup requiring 3-phase 208Y), Multi RS can't do what I need (since it's 230V only), but thanks for confirming it can do redundancy! Would be great if Victron put out a guide for "redundancy" or something to show which models can do that, and which cannot.

0 Likes 0 ·
nickdb avatar image
nickdb answered ·

There is no benefit for 2 vs 1. It uses more power, finds it more difficult to maintain the set point. Yes, if you installed them properly, you can reprogram one to be standalone, but in bad grids, 2 seem more likely to be a problem than 1. Unless for certification, always install 1, not 2.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.