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groningen avatar image
groningen asked

To ET112 or NOT to ET112

Dear All

I recently "became" a Victron owner and I am doing most of the installation myself. The learning curve is sometimes limited due to family (kids!! should i say more).

As stated above, I am not sure if I should use a ET112 or NOT? Let me explain.

I run a 48V system (Mulitplus 2 - 5000VA, CerboGX, SmartShunt, 150/45 MPPT etc) to power my 230V needs for my house (Grid tied). I will be splitting my DB box into "essentials" and "Non-essentials via the AC1 and AC2 output ports, therefore, all my loads will be after the Multiplus. Currently it is running already some loads via battery (but the mppt is not connected i.e. no solar feed).

I may not back-feed into the grid so I have to install (I assume) ESS with Zero back-feed function.

My headache started when someone mentioned that the ET112 response time is somewhat slow and they are running it with the internal CT to measure current/consumption. However, a V member pointed out that the ET112 is much more accurate and can capture data that can refine peaks, idle at specific time-frames.

So, should I use my ET112 or not when running all the loads through the Multiplus2 and will it work (no back-feed) without the ET112?

Hope my question is clear. Please let me know if I should add any information.

Mvg

Multiplus-II
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2 Answers
wkirby avatar image
wkirby answered ·

If you don't have any loads or AC-PV at all between an ET112 (or CT) and the AC Input then a meter is almost useless. The first current sensor would be the one inside the MultiPlus in that case, so stick with that.

If you are not allowed to feed back then you should not be running ESS at all. ESS means that the MultiPlus will be running in grid parallel mode, you'd need to notify your network operator of this type of operation.
Even with "no feedback" ESS, it is a best endeavour to not feed back but because ESS allows the inverter to run whilst the grid is connected, the fluctuations of the grid Voltage make it pretty much impossible to prevent feedback altogether.

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groningen avatar image
groningen answered ·

Dear wkirby

Thank you very much for the prompt response and information. OK, I will then exclude the ET112 from my DB. From all the comments and documentation that I can find, it is not clearly outlined what is the advantages or disadvantageous of the ET112 if you have no input or outputs before the Multiplus.

That being said, I suspect a lot of variations can be constructed with the equipment.

Regarding the back-feed, I am allowed (sort of, I know I said "not allowed), however, I wish to keep this for my batteries for when the grid fails (which happens regularly). Furthermore, our suburb "smart" meters are dumb, so it does not detect direction i.e. if I back-feed, it thinks I am using power (smack myself emoji).From what I can understand, (with ET112) feeds ever so slightly back when the load changes (i,e. oven switches off or geyser).

Then to crown it all, if you registrar as a "proper" back-feeder, you have to pay an additional admin fee every month and you get 10% of the value (per kwh) when compared to buying it (smack myself emoji). All in All, not the money or effort worth.


So would you suggest ESS then?


Mvg


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