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iammotorhomeless avatar image
iammotorhomeless asked

MultiPlus II AC-OUT 2 programming w/ VEconfigure3 Assistant

Hi
I have had my pair of Multiplus II 48/5000 (240V) running in Parallel for a couple of weeks now, and they are working fine.iammotorhomeless-2xmp-ii.jpg

Like a lot of people, I am still a little confused about the potential uses of the AC-OUT 2 !

I keep coming back to this video "Victron AC OUT 2 programming for Hot Water Diversion"
https://youtu.be/tJGP3G0P7no?t=93

I'd like to run more than just a hot water heater.
The list of things that I'd like to run, once the main house batteries are full, is endless. everything from spaceheaters or fans, to charging a second auxiliary battery bank.

MY QUESTION
what's the best way to trigger this. should I just use Battery state of charge ?
on at 99% and off at 98%
or is there a way to trigger it on excess solar ?
if I am exporting more than 750 watt, then on, and off again if less than 750 watts

"and a feature request to Victron... being able to switch them independently, so I could have one load off the master and a second load off the slave would be nice :)"


thanks in advance

multiplus in parallelAssistantsac out 2
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matt1309 avatar image matt1309 commented ·
Hi @IamMotorHomeless


I don't use the VEConfig assistant but I have "Hot water diversion". So may not be the answer you're after but thought I'd share just incase.


I instead use Node red on a GX device rather than VEConfigure assistant. For my setup node red is more flexible so thought I'd share as may be helpful for you. Node red also doesnt limit me to the number of built in relays (I can use multiple smart switches to control various devices)


I do what you suggest and have several checks in Node red, first I check if charge controller is in absorption or float mode (alternatively use SoC) then I check how much I'm exporting.

Depending on the amount exporting I then turn on different loads (via http request sent from Node red) controlled by shelly smart switches.

For example I have two water heaters a 3kw and a 1.5kw. If exporting >3kw I turn on the 3kw (controlled via http request sent from node red to a smart switch), then if < 3kw but >1.5kw exporting then i turn on the smaller. I have several other loads setup like this but those are the main two I use.


One thing I had issues with was having too small a margin between my "turn on load" and "turn off load" ie the load would turn on and use the 3kw and export would sometimes briefly become importing which would run my "turn off" flows in node red.

The loads would then constantly be turning on and off, so i just needed to add a larger margin between turn on and turn off criteria.

Turn off: If importing >500w over a period of time (I do 30seconds, ie I do the >500w import check then wait 30seconds then check again, and if it's still importing >500w thne loads are turned off).

Or

Turn off: SoC <90%


I'm still tweaking the system to be more accurate but this is what I use at the moment and it works well. (The 30seconds and 500w are arbitrary numbers that I've just spotted worked for my usual loads, I tweak these often to try find the best numbers)



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iammotorhomeless avatar image iammotorhomeless matt1309 commented ·

thanks Matt
I was trying to avoid using Node red... I was told, at the moment, it effects the Victron warranty. (sorry: I ment Victron Support)
I don't know if that's right or not.

but yes, I had not thought about using shelly smart switches, to cascade switching stuff on and off

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matt1309 avatar image matt1309 iammotorhomeless commented ·

Ahh ok, sorry about that I wasn't aware of that.


Shelly switches have been a game changer for me. A cloudless smart switch should be easy to find but i struggled until i found them.

They're getting fancier as well, think some have built in scripting that might be useful for you if relay options in VeConfig aren't flexible enough (yet).

Alternatively using an external raspi/server to read data from MQTT/Modbus from victron then use that raspi to control loads. Getting more involved/complex system then though i suppose so might not be what you're after.


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iammotorhomeless avatar image iammotorhomeless matt1309 commented ·

I have a raspi, I will look in to how to read the data from MQTT/Modbus, and see if I can do it that way

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matt1309 avatar image matt1309 iammotorhomeless commented ·

It should be quite easy in python or if you've got a home automation system home assistant/openhab already setup you could probably utilise that to do the logic for you. I don't know home assistant but openhab you could easily do this with rules.


The readme here might be useful for getting your head around MQTT

GitHub - victronenergy/dbus-mqtt: Venus OS service mapping the D-Bus on Venus OS to MQTT


Shout if you need a hand with MQTT/modbus or even openhab integration.

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iammotorhomeless avatar image iammotorhomeless matt1309 commented ·

@matt1309 I got it wrong... it's just no Victron support with node red

my local guy said he'll help.

so I just installed the Large version, and we'll give it a go

any tips, for a noob ?
what's the best shelly stuff to buy ?

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matt1309 avatar image matt1309 iammotorhomeless commented ·
Ahh makes sense.

Nah not really any of their smart switches will work.

I use Node red http node to send a get request to turn the shelly devices on and off via their internal IP (ie no need to connect to external clouds).

Only things to check before buying them is that the load isn't greater than rating of the smart switch (if it is then I would use shelly to switch a higher rated relay that would then turn the load on).

Not sure about your country but in the UK immersion heaters (electric water heater) switches tend to be double pole to switch both live and neutral. So you may need two shelly smart switches or a model that supports switching two switches.

I've tried shelly 1 (wifi only) and the shelly 4 pro. I'm a big fan of the 4 pro as I prefer ethernet however it is pricey.

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sharpener avatar image sharpener matt1309 commented ·

<Not sure about your country but in the UK immersion heaters (electric water heater) switches tend to be double pole to switch both live and neutral. So you may need two shelly smart switches or a model that supports switching two switches. >

The double pole switch with 3mm contact gap is to ensure isolation for servicing. You don't need to go to those lengths for control, ordinary immersion thermostats are only single pole anyway.

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iammotorhomeless avatar image iammotorhomeless sharpener commented ·

@matt1309 and @sharpener

yes.. I am in the UK
and yes I would think that double pole was more for isolation
thinking that just switching the active would be fine

and yes, I prefer a wired ethernet conection too. I just moved the HUB so that I could power it off the UPS, incase the ESS goes down

I just got node red dashboard up and running with 2 gauges
so. I'll go and have a look at the Shelly 4 pro, thanks

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derrick thomas avatar image derrick thomas iammotorhomeless commented ·
Where did you hear that? I can't see how using node red would effect the warranty, victron supplies node red embedded in the large os.
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iammotorhomeless avatar image iammotorhomeless derrick thomas commented ·

I was told that node red was still 'experimental' and you use it at your own risk !

is this wrong ?

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iammotorhomeless avatar image iammotorhomeless derrick thomas commented ·

@derrick thomas

Sorry, I got that wrong... (information overload) just watch the webinar again
it's the support that is not included, but my local guy says he'll help me anyway

so just installed the Large version, and we'll give it a go

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2 Answers
jacobjned avatar image
jacobjned answered ·

Hello.
The Inverter has no direct communication to the solar charge controllers and therefore does not recognise how much PV energy is being generated. It can "feel" the rise and fall of the battery bank voltage and/or current (and with this the inverter makes its own % SOC calculation via its internal battery monitor). Hence, one of the better options is to use the Inverter's % state of charge and/or battery voltage for AC Output 2 control via Programmable relay assistant. My comment on the % SOC window, I would suggest you make it wider, for example 5% difference as a minimum, i.e. 95% to kick in, and kick out below 90%. If you make the window too small, with surge loads and intermittent loads, it can kick in and kick out very often in a very short time frame.

Another option you can use and possibly combine with the above programme, is to have a look into the relay switches of the Cerbo GX. Run a separate load triggered via contactors perhaps, but please pay close attention to the relay voltage/current ratings. Some users have used the Relay Function: Generator Start/stop relay to trigger loads.

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iammotorhomeless avatar image iammotorhomeless commented ·
thanks, that does make sence..

and as I don't have a big battery, I might need to give it a good 'buffer'.

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Masquelier Pierre avatar image
Masquelier Pierre answered ·

for information:
1687362747187.png
my French idea on EasySolar 2 GX (2400W/ 3000VA). If the power consumed is low, you can assume that you have a significant surplus of solar energy. If it is the real case or not, you can switch the ACOUT2 relay ON and wait after the SOC low (75% for exemple) to switch OFF. If solar energy are realy available the battery's SOC will be not degrease. The total power grows up and you must wait a big delay to charge the tank and put OFF the relay. the relay is OFF after 4h (enough for a standard tank) or immediatly if the Victron's inverter is on overload (activate other essentiel load).

For long latencies, it is also necessary to control overload and watch temperature pre-alarm to stop the tank's process quickly for do not run an alarm. The process will be reactivated if all conditions are met.

Only the SOC is used to save battery life if you don't have solar energy enough. (not to activate the process for a long time on one shot, but you can made the calculus to have enough hot water for 25% or X% of SOC). It is essential to separate the function to protect the battery and guarantee enough hot water. It is a compromise you can experiment. In this assistant the behaviour in the case of weak solar, the batterie is used in tampon for charge enouth energy and discharge on the tank. it's like a "solar pump" and the SOC will grows up until the delay of 1200s is terminated. You can try other delais to manage the batterie with this minimal reserved AmpHour.
To stop the process in the night, the relais ACOUT2 is put OFF. It can be OFF by the MPPT solar relay with "day/nigh" detection or by a programmable clock who activates the AUX2 input (solution for my case).
An other advange of this assistant, is that you preserve the life of the AOUT2 relay (1200s min + time of discharge or charge of the battery by solar energy.) (not every 30s in other solutions).
An other advange is that you can install some derivative node to power on other load on ACOUT2. and if a load is not activate, an other load can switch ON. The time allocated for a heating iteration for example can be defined other than per unit of 4h.The allocation of this time can be played experimentally so that all loads relieved are active each in turn.

PIERRE


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