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daren-connor avatar image
daren-connor asked

Can the PV inverter support assistant be configured to start ramping down at 57.6v instead of 54v?

At the moment the absdorption saying is 57.6v for absorption but the PV inverter support assistant ramps down Fronius when the batteries are at 54v so it takes far too long to charge the batteries under solar. When the generator is on, it will charge at 180amps until 57.6v then go into absorption then float as it's supposed to but when it's under solar it will charge at 180amps to 54v then ramp down considerably so even though the charger wants the power the PV inverter assistant won't allow it. Can the setings be changed in the PV inverter support assistant to chasnge it from 54v to 57.6 as per the charger setting?

offgridFroniusAssistants
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daren-connor avatar image daren-connor commented ·

What would happen if the pv inverter support assistant was not used?

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daren-connor avatar image daren-connor commented ·

Is this Victron customer service? What an utter & complete waste of time. VICTRON IS BLOODY USELESS. Bloody equipment doesn't work right & your customer service stinks. F O

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2 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

The PV inverter assistant doesn’t support adjustable voltage threshold points at the moment, only frequency adjustments.

I agree it would be a good improvement and will pass along the feedback to the developers.

I believe this voltage point was chosen as the most reliable in testing to prevent overshoot.

Perhaps in your specific situation you could adjust the frequency points to allow more PV power later into the charge cycle. Be aware of the possible consequences though where the system overvoltage and shuts down if the PV inverter doesn’t respond quickly enough to changing conditions.

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daren-connor avatar image daren-connor commented ·

It just annoys me that I have as much solar power as I have generator power yet both charge completely different but use the same charger settings, the only difference being the PV assistant. It slows everything down to a trickle. My PV inverter is constantly in state 560 ramped down.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ daren-connor commented ·

I understand the frustration. We will get in touch with you to see if we can find a solution.

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porcini avatar image porcini commented ·

I have one question. If a 15S instead of a 16S LiFePO4 battery is used the voltage is even below 54V when the battery is fully charged. But PV inverter assistant can be used anyway. So what happens? Isn't that ill thought through? Lead acid has disadvantages here even though it is less sensitive against overvoltage. But with LiFePO4 the charging current isn't reduced?

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Paul B avatar image Paul B porcini commented ·

you get voltage overshoot on the DC charging and the inverters shut down

a solution that I used was to Install the relay in the Grid tie output and then connect this to the W1 relay of my mutlipus (I also use a hi low relay control so that the contactor was not connected to the multiplus relay. I then setup a assistant to open and close the relay based on battery voltage IF it was exceeded a set voltage. this then effectively turned the grid tie off. how ever this is basically a hard off for the grid tie. but it work for me.


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wayne-1 avatar image wayne-1 commented ·

Good day Guy,


Have you had feedback from the Developers on having voltage threshold points, to assists with fully utilizing the PV inverter?

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Andrew Ayles avatar image Andrew Ayles commented ·
Hello all. I also have a multiplus ac coupled to sma (10 kw pv, 5kw sma, 5kva 48v multiplus, 1700 Ah agm battery bank). At the time with larger daytime loads ac coupling seemed to make sense. Another big factor for me was also plenty of autonomy for the long spells of overcast weather we get in winter. With the multiplus ramping the sma down so soon on battery voltage with large battery capacity it results in the bulk/absorbtion phase often not getting completed while I sit watching vrm with the frequancy only .1 or .2 hertz off of the cutoff frequency for the majority of the day. I have played around with the frequency set points to try to increase the the charge current for a longer period of time but with no real success (it results in the sma shuting down due to instability or too many disconnect/reconnects). I have tried the sma with the changed frequency set points which seemed to work better but then on days with sun then cloud then sun i would get back to the unstable situation again with the sma shutting down. I then tried putting the sma on ac2 out with an assistant to shut off on high dc voltage just for these sun/cloud/sun situations but found it still was not a suitable work around . The conclusion i have come to is for people with ac coupling with large arrays and battery capacity victron need to look at making the voltage that they ramp the charging back at a set point that can be adjusted maybe through the pv inverter assistant (just as the frequency end points can be set in the assistant). I think this would make the ac coupling more versatile and able to cope better with both small and large battery banks and avoid us having to charge by generator.
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Chris avatar image
Chris answered ·

There is LITERALLY no logic to how it works from my experience.
I have two almost identical systems. Inverters / Batteries / MPPTs (all off grid)
Same settings in the Multis on both
Frequency shift works (very nicely) on one (this also has an AC PV inverter installed on the AC out.
It does not work at all on the other.

This is not an isolated case.

Drives me nuts

The documentation is also pants..... :/

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