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jonny-b asked

Multiplus II In Parallel With Grid

I've read some conflicting posts here about wiring up Multiplus IIs (and maybe other Victron charger/inverters) in parallel with the grid supply: some say it's not possible and some seem to have done it! Having weighed up the pros and cons, I've decided to go the parallel route with my newly purchased 48/8000 unit, Cerbo GX, and have ordered a couple of Pylontech US5000s to get me started. I have a pre-existing solar PV set-up with decent FIT payments, which should charge up the batteries for at least half of the year. In addition to the 'parallel with grid' discussions I've read on here, there seem to be conflicting opinions of what current monitoring works best, re: a Victron ET112 meter or an SCT013 current transformer. Can anyone please assure me that my planned install will work, and are there any other pearls of wisdom that can be relayed to me? Thanks in advance.

Multiplus-II
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3 Answers
l81ker avatar image
l81ker answered ·

You'll need G99 permission to connect it, and as its more than 3.6kW, the requirement is for a hardwired energy meter : you must use ET112 for the grid metering, not just a CT clamp type.

If you only want parallel connection (quite straightforward), you need a grid meter, another on your PV, and the only connection to AC mains is on AC IN on the MP2.

See this excellent video by Eliot Mansfield https://youtu.be/CgDcvJsrQHw

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shaneyake avatar image shaneyake commented ·
Can you explain why you can't use the CT? The CT has faster response and can be used to limit the inverter to 3.6kw.
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johnone avatar image
johnone answered ·

Just wanted to point out that the response above - that you must have an energy meter - doesn't tally with what Victron say. See diagram below. Also, the advice in the Eliot video - which concludes with only using AC In - probably needs checking against what Victron say in the ESS manual.w0h4edau8sk0ji4d.png


w0h4edau8sk0ji4d.png (72.8 KiB)
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l81ker avatar image
l81ker answered ·

FYI

Updated G99 fast track applications now allow a new "SGI-3" condition (Small Generation Installation) where the combination of all available generation on site is not more than 60A on a single phase and no individual device is above 32A. See details here: https://www.ofgem.gov.uk/publications/distribution-code-dcrp2108-fast-track-scheme and an example of it here: https://connections.nationalgrid.co.uk/get-connected/solar-and-wind/fast-track-g99/

Note that as @Johnone correctly states, if the ONLY generation device / inverter is the Multiplus 2 (connected as stated on AC in only and no external metering is used), the internal metering is type tested as "fully integrated" and no other metering is needed.



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