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MTS

Voltronics MKS inverter on off via serial command

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Hi Does anyone know if there is a serial command and the protocol for turning the AC output of a MKS II on and off?

I am trying to switch the AC output off if SOC drops below a certain value and then to bring it back once Li battery SOC has gone above a certain value.

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10 hours ago, MTS said:

Hi Does anyone know if there is a serial command and the protocol for turning the AC output of a MKS II on and off?

No. That's why Weber added Dynamic Load Control to our patched firmware. But there is no DLC for an Axpert MKS II.

10 hours ago, MTS said:

I am trying to switch the AC output off if SOC drops below a certain value and then to bring it back once Li battery SOC has gone above a certain value.

I think you'll need a partly hardware solution, like a relay with contacts connected across the rocker power switch (with the switch left in the off position, obviously). Then a small external computer (Arduino, Pi etc) to power the relay coil. I note that with the switch off and AC-in connected, the inverter will still power itself and loads from AC-in, but that's presumably OK in your application since the Li battery will still be spared the load. You might want to set utility charging to 2 A, so the Li battery doesn't slowly discharge due to idle consumption (some 35 W if the inverter is not operating). Consumption is apparently less than 15 W when "off" (no display etc). I would think it was a lot less than even that.

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13 hours ago, Coulomb said:

No. That's why Weber added Dynamic Load Control to our patched firmware. But there is no DLC for an Axpert MKS II.

Thx Coulomb. We have a STM32 micro controller with CAN for BMS control and serial connection to Voltronic. We have created a new lid for the MKII which has its own control and breakers / surge protectors and can use BYD and Pylon via our auto detect feature. Not for use with lead acid. 

 Our screen only has 4 selection options, charge mode (grid + pv or just pv), output mode  (sing or parallel), output voltage and powersave which makes it very easy for any installer as it auto detects BMS and battery capacity. More selections can be made eg  to de-rate for high temp conditions etc via 2g modem & remote cloud based dashboard.

We can adjust the low battery voltage disconnect to turn inverter off but can't turn it back on again without hardware solution or manual operation of switch. We tried adjusting the battery re-charge and discharge settings with Solar first option but that did not work. We have the relay option but want to scrap that as it makes the assembly a little more complex. We might need the relay anyway for PAYG option.

I would be interested in any views, particularly from Africa, as to our 'plug and play' approach which make the MKS II very easy to install with Li batteries, smart and connected via cloud. 

Is the MKS II firmware available as we would like to modify it ?

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9 hours ago, MTS said:

Is the MKS II firmware available as we would like to modify it ?

For a long time, there was none, but a few months ago, firmware version 71.71 became available.

But as far as modifying it, outside of the engineers in Taiwan with the source code, I only know of two people that can modify it. One of those (Weber) isn't interested in patching inverters with 450 V max MPPT and no insulation monitoring (such as the MKS II). The other is yours truly, and my time is quite limited at present. But it may be possible to do some limited patching; PM me if interested. Or if you know someone with the skills to do it, and I'm convinced that they are qualified, I'd be happy to let them have copies of the important files to save time. I warn you that patching is a quite time consuming process.

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