Hi. Hope someone can shed some light on this. I bought a new MKS 2  5kw inverter because it has a "blend" function, or rather a "chop between sources" function. Basically what I want to do is this: If my PV array provides 1kw and load is 3kw, the inverter must take the 1kw of PV and the shortfall of 2kw must be taken from grid. I can get this to work if I disconnect the batteries and run just from PV and Grid. If I connect a clamp meter to the incoming wire of the inverter I see around 8amps. The 3kw load is consuming 13-14amps so the difference must be coming form the PV.

But I cannot get this to work when the batteries are connected. If the load is less than what the PV can give, the inverter runs only on PV. As soon as load exceeds what PV can give, the inverter draws from battery. When batteries reach the cutoff voltage of whatever I set it at, the inverter goes to bypass mode and supplies the 3kw from the grid. The PV then recharges the battery. As charging tapers off at near full (Flooded batteries),  the charge current drops to a few amps so the full PV power is not being used. When the bat eventually is full, the cycle repeats. Load supplied from PV AND battery. Then back to bypass. So during the time that batteries are charging again most of the potential power from the PV is not being used.

I'm sure it's a setting that's not right.

I've tried combinations of settings SBU etc but can't get it to work like i want it to.

Basically what I want is when the load exceeds what the PV can give, that the shortfall is taken from Utility only and nothing from the batteries (provided they are at 100%). 

It works like that without batteries connected, why can't I get it to work when batteries connected? 

I was led to believe the MKS 2 could do this?

Anyone had experience with this?

Hope someone can assist

Edited July 4, 20196 yr by impi62

1 hour ago, impi62 said:

I was led to believe the MKS 2 could do this?

I'm not actually allowed to answer but from what I have gathered overall, nope, it cannot. Off-grid inverter.

But I may be wrong!!!

The King is more suitable for what you want to do.

7 hours ago, impi62 said:

I was led to believe the MKS 2 could do this?

I suspect it's capable of it, but it may not happen if the battery is present.

The manual for line mode says in part: "If "solar first" is selected as output source priority and solar energy is not sufficient to provide the load, solar energy and the utility will provide the loads and charge the battery at the same time". The problem with this is, if it tries to charge the battery from the utility, it will have to use the inverter in reverse, and it needs the inverter in the forward direction to push solar power into the load. So perhaps you need to put in in a mode where it can't possibly charge the battery from utility. So I suggest you try this combination, if you haven't already: setting 01 (Output source priority) to SOL (solar first), and setting 16 (Charger source priority) to "OSO" (only solar).

If that doesn't work, then it seems that they have deliberately avoided this possibility. Maybe it's to placate the supply authorities, who seem to hate the idea of household batteries generating power into the grid.

Your inverter will have to be in line mode for utility and PV power blending to work; in this mode, the LC Display shows "BYPASS". In battery mode ("BYPASS not shown), there is no way on this model for utility power to get to the load, and hence supply part of the load power.

Please let us know how this goes.