question

rag avatar image
rag asked

Victron minimal setup

hi,

I have 2 eg4 batteries(48v, lifepower4). I plan on buying a multiplus2 48v. Do I need anything else to configure this setup? Assuming I can install the ve-configure sw on pc and connecti without any other adapters in-between?


Couple of other questions:

- I don't think the eg4 batteries can communicate with multiplus as per other threads. Is there any danger of it being overcharged or drained fully

- I plan to charge the batteries at night and discharge during the day. Assuming this is possible with ve-configure

- anything else I need to be aware of?


thank you

Multiplus-IIvictron
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4 Answers
Alexandra avatar image
Alexandra answered ·

@rag

You will need an mk3 to usb adaptor to program (unless you want to use a gx and do it over the vrm.)

You program in the correct battery chemistry and charge parameters including the low dc cut off and you will be fine. I have a few systems in with what are considered dumb smart lithium batteries without issues. Most of the time if the parameters are incorrect the battery protects itself anyway.

The charge a discharge schedule can be done through either the GX with programmable times, or other methods with contactors depends on how you want to tackle the issue. Or a combination of both.

There is also the option of node red which is a bit more advanced.

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rag avatar image rag commented ·
thank you @Alexandra. I have configured a raspberry pi instead of the gx. I was looking at the ESS assistant/ve.configure and it wants a grid type. Do you know what grid type I should use for the US? (I don't see one in the list)
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Alexandra avatar image Alexandra ♦ rag commented ·
@rag

A RPi is considered to be a GX device in your installation.

There is no grid code for the US.

I am not sure of the legal implications of installing or having it on your system. We use grid code other where we are in Africa, but then laws here are not so strict, here, there is just one requirement and that is we do not feedback without permission/correct meter.

Are you in a mobile installation? In that case you should not use ESS at all.

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rag avatar image rag Alexandra ♦ commented ·

hi @Alexandra,

It is a home installation. I am not sure if ESS assistant is the correct way but what I want to do is charge my batteries at night and discharge during the day. Is there another way, other than ESS, to do that?

I have attached an image of what it kinda would look like(no solar)

bat.jpeg


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bat.jpeg (116.8 KiB)
rag avatar image rag rag commented ·

couple of more questions:

- I have a 40 amp AC in circuit breaker and an AC output 40 amp breaker. Both 8 awg cable. The below is from the multiplus manual. Assuming my wiring is ok. Do I need to change out my breaker to 30 amps on both sides or 40 is ok?

>AC input current limit 32 A for 3kVA and 50 A for 8kVA and 10kVA (= adjustable current limit for PowerControl and PowerAssist functions)


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shaneyake avatar image shaneyake rag commented ·
What state are you in? Using ESS in the US varies quite a bit by state as the inverter is not UL listed.


Which Multiplus-2 did you end up getting?

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rag avatar image rag shaneyake commented ·

oh, did not know that. I have not put in the order yet. I was planning on getting multiplus 48v/3000 I am in Texas and not planning to sell anything back to the power company. It will be an offgrid system. AC-in to the inverter is from the grid though

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Alexandra avatar image
Alexandra answered ·

@rag

With no solar and ESS being a debated legal issue, i would say then an AC ignore system would be more ideal.

There are several ways to acheive it.

1. You can use and external mcb timer switch to connect and disconnect.

2. You can use a GX and run the grid lile a generator. There is an article here for that. It is slightly more complicated than the mcb timer. Not sure if you planned on having one.

3. There is node red, but as a new person maybe something you can play with later. Also requires the GX.

4. Using virtual switch - or condional connect, but this cannot be time based.

Your incoming breaker is fine. The input current limit can be set easily. The output depend on the circuits you are running.

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rag avatar image rag commented ·
hi @Alexandra, 2, 3, & 4 looks like a good option. mcb timer - think I have to do some wiring/install changes. Could you give me some more info on 3 & 4?


thank you


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Alexandra avatar image Alexandra ♦ rag commented ·
Sure. Virtual switch.

Node red here is the start document. On Victron Professional there is a training session coming up at end of November. So sign up there to catch it. And a dedicated topic on the forum.

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rag avatar image
rag answered ·

hi @Alexandra , @shaneyake - Does the ESS rules only apply if you are sending energy back to the grid? I don't plan on doing this. It is an offgrid system with AC-in from Grid. Assuming Multiplus II 3k / 48v is good for this..let me know if it is not the case

thank you

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Alexandra avatar image Alexandra ♦ commented ·
@rag

ESS features are designed for on grid use. So really not much use off grid.

And if you install a grid code sometimes a generator can be a fiddle to be accepted by the inverter as it almost has to be grid quality.

So in both the ESS and grid code unnecessary or useful in an off grid setup.

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Alexandra avatar image Alexandra ♦ Alexandra ♦ commented ·

Does your generator support remote start?

If so then the relay on the gx can be used to set that up and shut it down as needed based on time or on battery State of charge.


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rag avatar image rag Alexandra ♦ commented ·

hi @Alexandra , I don't have a generator. All I have right now is 2x48v batteries and plan on getting the multiplus 2/48v/3k inverter. Just need to charge the batteries at night and discharge during the day. Would #2 option you mentioned still work for this?

>2. You can use a GX and run the grid lile a generator. There is an article here for that. It is slightly more complicated than the mcb timer. Not sure if you planned on having one.


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Alexandra avatar image Alexandra ♦ rag commented ·
Yes if you have grid available. All it does is interface with the primary contact inside that closes the connection to the grid. And then allows you change your progamming or times through the GX as you want to, without having to reprogram the inverter with the mk3 every time.
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rag avatar image rag Alexandra ♦ commented ·
hi @Alexandra, so that will work even if you doing have a generator. That is good news. Thanks for all your help




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rag avatar image rag rag commented ·
hi @Alexandra ,

I was able to run the generator relay (without a generator) for an hr. Can I assume that it will switch to battery during this time as that is the only other source I have. Once this function is done, it will switch back to grid. The article you mentioned had some assistant functions which I did not follow. Hopefully I don't need those

Also, what is a good way to configure the system to charge the battery at a certain time? like between 8 and 9 pm

thank you
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Alexandra avatar image Alexandra ♦ rag commented ·
@rag

If there is power on the AC input of the inverter, is is not going to be inverting.

Choosing when the battery charges is also a bit complicated.

And one hour of charge unless you are charging at a very high rate will not be enough for a good charge for your batteries to remain healthy.

Unless I am misunderstanding what you want.

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rag avatar image rag Alexandra ♦ commented ·

hi @Alexandra ,

So my requirements are simple and not sure if easy to implement :-)

- what I have : batteries, multiplus and grid power

- all I need is to charge the battery at night via grid and discharge during the day and if the battery falls below a certain voltage/soc, switch back to grid

- I need to charge the battery at night since I get free power from 8 pm to 5 am

What parts can I do with option 2 or any other method? Sorry for the long drawn out thread

*one hour was just as a test but it could be longer

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rag avatar image rag rag commented ·

found one : #3 with node-red

https://github.com/victronenergy/node-red-contrib-victron/wiki/Example-Flows

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shaneyake avatar image shaneyake rag commented ·

This is possible and not that hard to do.


If you aren't able to use ESS then you will need to island during discharge.

option 1: Generator control on GX controls AC input contactor via AUX1 input using GX relay.
This is easy but has some limitations.
You can do it with virtual switch or Assistants
https://shaneyake.blogspot.com/2022/09/victron-disconnect-inverter-from-grid.html

option 2: NodeRed, can directly control the AC input contactor by changing inverter from ON to Inverter only. My blogpost has an example of this. You can then just set up a timed injection to connect and disconnect from grid.


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rag avatar image rag shaneyake commented ·
hi @shaneyake ,

#1 looks very complicated since I am a newbe:-) but will take a look

#2 looks easier. I have installed venus large/node-red on raspi but have not read all the doc. I see that you link has the image of what needs to be done. Is it possible for you to export the json so I can import directly? I am waiting on my inverter so it would probably fail right now. I will start reading up..


thank you


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rag avatar image rag rag commented ·
I see the power of node-red -- amazing. Thank you for all your help
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rag avatar image
rag answered ·

1 - Charger Only
2 - Inverter Only
3 - On
4 - Off

So how do you do mains on, charge off? I basically don't want the battery charging when #3(ON) is chosen. Right now it goes 'mains on, bulk on'. Need bulk off

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shaneyake avatar image shaneyake commented ·

The inverter can go into passthrough mode but unfortunately I don't know how to do that without enabling ESS.

You can lower your input current limit to match your loads which would stop it from charging but could also result in it discharging so you might need some logic to change current limit as loads increase.

You can also use the AUX1 input on the inverter to limit the charge current.

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rag avatar image rag shaneyake commented ·

it is kinda working..so I have it set to 'charger only' at 8 pm. It switched to bulk-->float-->off and all loads seem to be running via grid, which is good. I have it set to 'inverter only' at 6 a.m so it should work(hopefully).

1) when in off state lot of stats go away..hmm

2) When it switches from inverter to charge, it shuts down all the equipment for 30 seconds so all the clocks/etc need to be reset. Anyway for it to not shut down before it switches state?


thank you


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