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Bobby avatar image

ESS + Multiplus II + ET112 = backfeed?

Good day all,

So living in South Africa, any amount of backfeed causes our utilities "Smart" meters contactor to trip and disconnect the utility grid.

I have 12x330W solar panels and 48V battery bank. Every now and then I did see some small backfeed even though the option to "Feed-in in excess solarcharger power" is disabled which tripped the utility meter and they had to come out and reset it in order for it to work again.

I setup in my ESS Grid set point to 60W just to have some kind of pull and I am not too happy to increase that further.

Very simple question - would installing ET112 Energy meter between the utility "Smart" meter and my Multiplus II prevent backfeed to the grid?

Multiplus-IIESSEnergy Meter
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I have a question. Are you on a prepaid meter. The South African prepaid meters will trip if their is any feedback.

4 Answers
SolarHack avatar image
SolarHack answered ·

Hi

Two things you need to consider. ,

  • The first is Exsolar have a device they claim can stop grid feedback (Never tried it but maybe its worth looking into) https://www.exsolar.co.za/uploads/8/0/1/3/80134398/smart_energy_controller_brochure.pdf
  • According to City power they are exploring allowing you to feed in and be paid for it and will have a policy by midyear 2021 (Lets see if that happens). They do state that prepaid meters will be excluded and only sites that meet the regulatory standards (Your Multiplus II does) as well as have a post paid meter will be eligible.


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That device looks interesting...I'll definitely check it out, thank you!

Bobby avatar image
Bobby answered ·

Is there any device that I can get in order to achieve no backfeed?

Or maybe any other config besides ESS that can achieve it?

This is a really big problem in South Africa, as my grid meter will keep tripping :(

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Hello from South Africa. The fix here in SA is to replace your pre-paid meter with one that's less sensitive. The one I installed last year works fine (Cape Town).

Also from SA. If you can, ask to have a Landis+Gyr pre-paid meter installed - but not the smart-meter type, only the standard pre-paid meters. I have an installation with a MultiPlus II 5000, which I have installed first in one property, and then in another. Each time, I asked for the L+G pre-paid meter to be installed. In each case, the ESS was set to not feedback, and the ESS grid-point setting was just 10W. Although the regulation of the MultiPlus is not good enough to prevent **any** feedback, these meters will tolerate a certain amount.

[Full disclosure - I used to work in software for L+G for 30+ years until retirement end of last year. The way the standard L+G pre-paid meter works, is to accumulate the reverse power, and if it exceeds the accumulated limit, then it will trip. But any forward power reduces the accumulated reverse power, so generally, you are always on the "good" side of the meter's limit. For example, if you have 20W reverse power for say 10 seconds, the meter won't trip yet, and then if you have 20W forward power for longer than 10 seconds, it will wipe out the reverse power measurement. I am not sure what the actual accumulated limit is, but I have never had mine trip for this reason at all. Most other pre-paid meters (and I think, the smart meters) measure the instantaneous reverse power, instead of the accumulated reverse power, and thus they tend to trip much faster.]

Hi guys,
I am in JHB....
I am going to apply for prepaid meter from City of Joburg. Do I ask them for Pre-Paid meter options or do they just come and install Hexing or whatever they prefer?

laurentiu.pitran@gmail.com avatar image
laurentiu.pitran@gmail.com answered ·

Hello,

there is not ZERO feed in a ESS system; this is truly impossible, as it was marked out in few posts till now.

More of this if you have in your home as load some devices as ironing machine for clothes press, some washing machine that need to heat up the necessary water or a heat pump, you will have more injected energy in the grid, even you set ZERO injection.

Practically, switching continuous necessary power from an ESS system is making this one to need more time to regulate the power as the result is injection on grid....

attached you can see the graf for today in my ESS system '; counting this energy it is a sum of 2,08 kW for today....

There is another aspect for this energy that is injected on Grid: during day, when is enuff sunny on sky don t have much importance for me, but during the time that i use energy from battery is a BIG mess - hope that can be corrected in time.

Just added in -now is second from top- of this post the record of injected energy in grid for each phase.

Just for information, i will add a new graph that will show the energy injected on grid per each phase( is the same of the previous one, that it was total, now per phase ) in the same time it will be the energy for each phase for the load at that moment, that is particularly a expresso machine. This is FIRST from top graph.


example.png (84.8 KiB)
example-2.png (114.2 KiB)
example-3.png (100.1 KiB)
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Paul B avatar image
Paul B answered ·

It would give the Inverter better control and thus should help stop the small issue. but I would NOT guarantee it in any way shape or form. I myself have not tested it to that fine a level.

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