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ET 340 on 3 phase installation with single phase ESS system.


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My client wants to monitor whats going on on hes other phases consumption wise as he lives abroad. at the moment he has a 10 Kva victron system on hes 1 phase that carries most of the house.

Will this complicate or confuse the ESS system or will he be able to see hes consumption total and peak records on the VRM portal  for each phase ?

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First off, I want to recommend installing an EM24 meter instead of an ET340. While both are supported, the ET340 does energy accounting incorrectly. I will explain lower down.

Secondly, yes this is a supported use case. The total power over all three phases is taken into account, and then ESS tries to cancel it out in exactly the same manner as it always does. The result of this is that the Multi on L1 will feed energy into L1 in an attempt to cancel out what is used in total over all three. This obviously assumes that you are billed for the total across all three.

As an example, if you have 500W on each phase, the Multi on L1 will feed in 1500W of energy, 500W of which is used by the loads on L1, and the other 1000W flows backwards into the grid but is cancelled out by the 500W+500W on L2 and L3 to get to an overall zero.

Caveat: The Multi must be on L1. If it isn't on L1 (from the perspective of the supply company), then you have to pretend that it is and mentally renumber the others so that the phase rotation remains correct.

Second caveat: Supplier must bill you for the total over all three. Otherwise you must turn off phase compensation.

Now for the reason you want the EM24. Keep in mind that these meters have separate counters for imported and exported energy. Now consider an example where I import 1kw on L1, and export 500W on both L2 and L3. The total over all three phases is then zero. If I do this for an hour, the energy counter on L1 will be at 1kwh imported and 0kwh exported, while the energy counters on L2 and L3 will show 0.5kwh exported and 0kwh imported, and the total energy counter on an EM24 meter will show zero for both the import and the export.

If you perform the same test on an ET340, the individual counters show the same values, but the total energy counter will show 1kwh imported and 1kwh exported. While this is technically true on some level, you could have derived the same answer from adding the individual registers. For systems that does phase compensation, this causes the main energy chart on VRM to be... well... wrong.

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