question

@JohnJayMack

To run ESS a grid code must be selected. So it must comply to that standard and be a fixed install. If people are not following that then it is on them. The warnings are there.

Grid code - feeding from DC not allowed -does not allow feedback and does not allow the ESS assistant to be programmed at all.

Grid code other allows the user to alter LOM detection and even disable it. So you will be non compliant. And if it is not a fixed install (because of feedback) there can be dangerous voltages at the input for a few seconds before relays open.

If you need generator warm up and cool down then assistant/relay programming (or going back to the good old days) is what you need to do.

Thank you @Alexandra for the response. I have asked another question that I would like you to look at entitled:

ESS, LOM, and Feeding from DC to grid not allowed

In that question, I have pointed out an inconsistency in the operation and documentation. To summarize, the connections of the inverter are the same whether used in a No Power fed back to the Grid and in a grid-tie usage. In a No Power fed back, the Inverter evidently has a Code Approved Loss of Mains function to disconnect the internal transfer switch from the external power source if the external power is lost. This code approved LOM function disappears if ESS is activated.

You wrote "Grid code other allows the user to alter LOM detection and even disable it." If this is the case, the LOM configuration that exists for "feeding from DC not allowed" should be available and using that configuration for LOM should give the same code compliant behavior as using grid code " feeding from DC not allowed."

I guess my basic question is how the LOM function is good enough for non-ESS use but is not good enough if ESS is enabled. The physical external connections are the same and the internal transfer switch is the same. In normal use, if the incoming power is insufficient for the load, the inverter will use DC battery power to increase the output. This is called an "assist function." In this case, the inverter power is running in parallel to the incoming power. If the shore power fails or is removed at this point in time, the internal transfer switch must detect the LOM and drop immediately. If it does not, then DC power inverted to AC will be present on the incoming plug. From my reading of the literature, the Multiplus II, in non-ESS mode, will prevent the problem. But turn ESS on and suddenly the LOM is not capable of preventing this issue.

I wonder if this is a case of different internal departments at Victron not communicating with each other. The department responsible for the non-grid-tie use have determined that the LOM function is code compliant. Thus, my use without ESS is "safe." The department responsible for grid-tie use looked at the same LOM function and decided that in a grid-tie application, the LOM function does not meet code.

I spent 40 years in the Elevator industry and personally know of at least one instance where two engineers at the same company sitting side by side came to opposite conclusions regarding code approvable for a passenger elevator control system. After a conference, an agreement was made.

I may have over simplified this issue and I hope someone can help make it clearer.

Thank you for staying with me, @Alexandra. Your response caused me to dig a little deeper into the manuals. I interpret from some research that in the "None" setting for grid code, the Multi monitors grid current and only inverts to boost output power when input power is insufficient. This is probably not consider a true LOM function.

It is sad that using a generator properly meaning being able to warm the generator up before a load is applied, and cooling the generator off with no load before turning the generator off is only available when ESS is enabled. I am using the Color Console to monitor and control my system. The Generator control is very robust, but significantly lacks the warmup and cool down functions without ESS enabled. I can and will hack the system to gain these functions, but it seems to be an oversite not to provide the functionality in the basic generator control.

I may try ESS since I may have external LOM functionality already in place. If I do try the ESS functionality, I will take responsibility for the safe operation.

Also, I will have to test to see if the Ignore AC 1 must be enacted of just one inverter as the manual suggests, or must be enacted on both inverters as you suggest. Once again, thanks for your help.