Programmable relay (AC OUT 2) bug

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boristhespider asked Jan 9, '21

Programmable relay (AC OUT 2) bug

I've connected a relay to one of the AUX inputs on my EasySolar-II GX to control the AC OUT 2 relay, thus overriding the default behaviour of AC OUT 2 (ie. load shedding when AC input is not available).

My relay allows me to force AC OUT 2 on (after checking load will be low enough of course) during an outage of AC IN.

I also want the default behaviour (that AC OUT 2 is disconnected when AC IN is lost, and that it is reconnected after AC IN has been available again for a given time).

To that end, I have two programmable relay assistants configured, one to turn the AC OUT 2 relay off, and another to turn it on, I have them configured as follows:

1. Programmable Relay

- Use ACOut 2 relay
- Set relay off
- When AC1 not available for 0 seconds

This assistant above works fine, the load is shed as expected if AC IN fails.

2. Programmable relay (1)
- Use ACOut2 relay
- Set relay on
- When AC1 available for 120 seconds
- When auxilliary input 2 is closed for 0 seconds

This is not working as expected - the part about aux2 works fine (the external switch controls the relay and AC OUT 2 can be forced on during an AC IN outage), but the part that should turn AC OUT 2 back on after AC IN has been available for 120 seconds is triggered too quickly.

What happens is that AC OUT 2 switches on exactly 120 seconds after mains power on AC IN is restored, NOT 120 seconds after this power has been accepted by the EasySolar.

What I mean is that, in VeConfigure, I can see the blue bar on the left (or under the popout bigger VE. Bus Monitor window) ticking across as the quality of the mains power is assessed by the system prior to accepting it.

After 120 seconds, even though the mains power has not yet been judged to be of appropriate quality to be accepted (this time can vary in my installation up to some tens of minutes), the AC OUT 2 relay will close. In actual use, what will happen as a result is that the sheddable loads on AC2 will be powered again before the AC IN power has actually been put on the bus, and so the inverter could be overloaded and shut itself down.

The delay specified in the assistant should be from when the power is accepted, not when it is first connected.

Assistants

2

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Ingo commented · Jan 09, 2021 at 06:06 AM

"This is not working as expected - the part about aux2 works fine (the external switch controls the relay and AC OUT 2 can be forced on during an AC IN outage), but the part that should turn AC OUT 2 back on after AC IN has been available for 120 seconds is triggered too quickly."

I have the EXACT same problem and have been trying to get Victron to look into this for more than a year without success. I have regressed firmware and also loaded the latest firmware - no change. This used to work so I can only conclude that it's a bug in VE Configure and that the Relay Assistant is not correctly loaded to the unit as the actual Relay Assistant hasn't changed for +2 years if I remember correctly.

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Paul B commented · Jan 09, 2021 at 06:13 AM

I understand your point but is it that an important change when you can just extend the 120 sec setting to allow for the max sync time. some others may want to use the input figure as and when it arrives and not when its synced etc, I myself cant really see the issue, so could you please ex-plane some more as to why its a problem

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Answer 1 · 2021-01-10T09:47:05Z

Mark answered · Jan 10, 2021 at 09:47 AM

What you have described is not a bug with the programmable relay assistant and 'AC input' switch condition; that condition is most commonly used when you want to 'Ignore AC input' for a given period, such as when it's desired to give a generator some time to warm up after start up before applying load to it.

As an aside, if the MultiPlus takes more than a minute or so to synchronise to your power source, then the quality of the AC power being provided must be extremely poor, and that should probably be looked at/improved.

Anyway, if you want to trigger based on the time that the power is actually accepted, then consider using/trying the 'Charge state' switch condition (with the 'when charging' option selected) instead of the 'AC Input' switch condition; that should acheive the logic behaviour you desire.

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Answer 2 · 2021-01-12T17:12:03Z

boristhespider answered · Jan 12, 2021 at 05:12 PM

Hi Thanks for the replies all.

Paul B - I cannot simply extend the time, because I can´t be sure how long the system will take to accept AC IN, I seem to have a bit of an issue with my system because when AC IN returns, the unit commonly takes many minutes to accept it, even though the quality of the AC seems fine (it is grid power, and the frequency/voltage are stable etc). The system can sometimes accept it within a couple of minutes, other times it will take half an hour or more. I have tried tracking it down, but can´t determine what it is, I believe it might be something on the output side of the easysolar (like a UPS) that somehow upsets it, but I can´t be sure, and in any case it´s no big issue because the power is always eventually accepted and used, and it never trips back out after being accepted.

Mark - thanks for the pointer, regarding using the charge state condition, does that change based on whether the AC charger is charging the batteries? What I mean is, does it mean "batteries are charging" (from any source, be it PV or grid) or specifically that they are charging from grid? Also, and I´m only guessing here, but would this condition not be satisfied when the batteries didn´t _need_ charging, so say AC returned and the target SOC for ESS was 60% but the batteries were actually at 70% (say from PV charging them) wouldn´t the charge state remain "not charging" so that the condition didn´t get satisfied?

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