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MyPV AC-Thor in off-grid system - settings?

Hello,

the manual (https://www.victronenergy.com/live/actor_offgrid ) says that when using AC-Thor in an off-grid system frequency shifting (PV-inverter assistent) has to be activated at the Multi.

- Is this also necessary if only DC-coupled PV is used (no PV-inverter on AC-out)?

- what are the frequency settings in the "PV-inverter" assistent? Are the default-settings ok?


Best regards

offgridAC PV Couplingfrequency
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4 Answers
Robert Bazalgette avatar image
Robert Bazalgette answered ·

I think I finally sorted this out. The issue is the way the PV assistant works with different types of battery. This system has LiFePo batteries. The recommended absorbtion voltage setting for these is different to the default setting in Victron connect. When selecting Lithium batteries in the charger setting, these levels are fixed, not adjustable. I had selected 'user defined' and put in the recommended settings for this battery. The PV inverter support app uses different voltage levels for lithium batteries, and again this is not adjustable. In my set up the assistant was waiting for a target voltage that was never reached.

The solution required me to accept the fixed levels for Lithium batteries, ignoring the recommended levels. If I need to make a warranty claim for the batteries this may give me a problem.

The Victron fixed absorbtion level is more than 2 volts below the recommended level.

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Robert Bazalgette avatar image
Robert Bazalgette answered ·

Having a bit of a nightmare with this. The Multi simply does not do what the assistant is supposed to do. Here is a screen shot. It shows that when the day breaks the power ramps up until the battery is full. Then the power drops, battery remains at float, but no frequency shift, and no power to the immersion. Can anyone suggest what might resolve this

1622805735333.png


1622805735333.png (1.7 MiB)
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gregn avatar image
gregn answered ·
Hi, in this system the PV assisant in the Multi will start control at 51 hz to 52 hz, but in the Ac thor it is written : 50.1 Hz (start) to 51 Hz (end). For me it does not sound logic but can you please confirm.
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Hi @GregN

You either have to adjust the AC Thor settings to the Multi's, or adjust the Multi's setting to the AC-Thor settings.

Also: please check with local regulations if it's an on-grid installation.

Hi, I am having an issue with the same devices. The system has a Multiplus II GX 5000 48v inverter charger, with a Blue solar 250 / 100 solar charge controller, and LiFe Po battery bank 216 Ah. With My PV Thor seyt to frequency control. I have added the PV support assistant, with settings start at 50.1 Hz - 51.0 Hz. The Thor has the same settings. Initially it worked as planned for the first two weeks, but now the frequency is staying at 50 Hz, so no water heating. Today the MPPT charged the batteries up to the Absorbtion set point in the morning with up to 1.6 kw. (Solar Array is 5.2 kw). It had completed that by 11 am. Now the batteries are at 53.5volts, the MPPT is reporting 0 watts, even though there is some brightness in the sky, clearly enough to do something. AC load is around 100 watts.

I don't understand why it is not implementing frequency control to use whatever surplus is available. Any ideas ?

The system is visible on the VRM portal.


Lucian Popescu (Victron Energy Staff) avatar image
Lucian Popescu (Victron Energy Staff) answered ·

Hi, yes,that assistant will control the ac-thor device through frequency shifting. Leave all the assistant settings on default

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@ Lucian!

Is it right that the Multi can do the frequency shifting also if there is no AC-coupled PV (only DC-coupled PV)?

Does the Multi get the information for frequency shifting from the CCGX when surplus power is available at the MPPT?