Electrical schematic contactors and BMV702 Relay

[Cef]

Hi !
I wanted to show you and contribute the schematic that shows what I'm finishing in my home and that shows the use of the BMV702 relay.

I am doing in my house an exclusive circuit for high consumptions that groups appliances: Air conditioning, washing machine, dry clothes and various other items that can be connected in the kitchen such as microwave oven, toaster, blender, etc.

The idea is that when the Main electrical grid is running, there is energy in both the exclusive high consumption circuit and in the rest of the home, since if PV Energy (not shown in the diagram) is not enough, the rest Of power is provided by the grid

In case of a cut in the main power supply, Contactor 1 is responsible for:
1. Operate the alarm (buzzer + flashing light): This alerts my family and tells them that the house starts to operate only with solar power (if available) and battery power (with a switch this alarm can be turned off).
2. Make a cut of all appliances connected to the high consumption circuit.

Contactor 2 has the function to protect the batteries from a dangerous discharge
Since the BMV is configured with Inverted Relay, this is Normal Closed, parameter 16 is set to keep the relay in its state until the SOC drops below the 55% value. When this occurs the contactor is opened and the loads are disconnected.

 

[___]

All you need is a bypass switch on the inverter, for when it needs to go for repairs and so... :-P

[Cef]

7 hours ago, plonkster said:

All you need is a bypass switch on the inverter, for when it needs to go for repairs and so... :-P

Yes plonky  and thanks for your observation , the bypass switch is critical. I did not add it in the schematic since the purpose of it was to show only the use of contactors and Relay of the BMV702 and I did not want to complicate it with the complete scheme of my installation that includes devices of protection against lightning surges of measurement of imported energy And exported, reading, signaling, etc.

Good, i show a photograph of the By Pass switch (red key) from one of my boards.
The switch in question allows you not only to perform maintenance, but also must be there and your family should know it because if you are traveling or outside the house and the current Inverter is burned, it enters into fault condition or any other disaster that leaves your home without power, any member of your family can turn it to reestablish the service as if it had never done a solar installation.
If any member of the forum needs to know the wiring of the same, let me know and upload a picture of the connection scheme of the same.

 

[___]

That's a very neat little board :-)

[Cef]

Yeah !!  I am very limited with the space of the place of installation... 

[Cef]

Hello
Here I add the schematic that shows the modification that I made to avoid having to use the Relay of the BMV702 in Inverted Mode and with this that the coil of the same must be permanently energized, which although in principle should not be an inconvenience is something that I prefer .
The "Contactor Number 3", which may be of the smallest amperage available on the market, has as its sole function the use of its Normal Close Auxiliary Contact for the "contactor 2" control.
I hope that it would be useful to someone !

 

[___]

Isn't switching the Neutral slightly frowned upon nowadays? :-)

The coil of the relay in the BMV probably draws a few tens of milliamps at most :-)

[Cef]

15 hours ago, plonkster said:

1) Isn't switching the Neutral slightly frowned upon nowadays? :-)

2) The coil of the relay in the BMV probably draws a few tens of milliamps at most :-)

Hi Again @plonkster

1) Excuse me. English is not my first language and I can not understand what you mean. Can you explain in other words the problem of the scheme you see ?

2) Of course, very low. From the following image of the BMV702 Manual it is observed that for a 48 volt system the consumption may be in the order of about 4 milliamps.

Now if the comment was because the third relay is not necessary, I agree with you, but "tastes are tastes" or maybe the language expression would be: "question of taste", there are people for those milliamperes of consumption during the use of batteries may want to avoid them and on the other hand I have read that some people think that the wear of a coil is greater if it is permanently energized ...

Well .. in my case I decided to use it  for the two previous reasons and  because that third contactor already had it and also some space in "my little boards" . Then I put pictures of these 3 contactors ...

[___]

21 minutes ago, Elmichi said:

Can you explain in other words the problem of the scheme you see ?

Contactor 3 switches the neutral side of Contactor 2's coil. I'm not sure exactly what the rules say, but tastes are tastes as you say... I would place the switch in the live line.

23 minutes ago, Elmichi said:

some people think that the wear of a coil is greater if it is permanently energized

I don't know too much about that, but I hope not. I have a contactor on my inverter's input wired to the Ziehl anti-islanding device, and that thing is permanently on. When it's quiet at night, you can hear it hum. Can't do it any other way either... you need it to drop out when the power fails.

You're essentially using a contactor to invert the signal. I can think of ways to do this solid-state (opto-coupler, TRIAC), but it would take some time to explain that, and frankly... this will work fine as it is. :-)

[Cef]

58 minutes ago, plonkster said:

Contactor 3 switches the neutral side of Contactor 2's coil. I'm not sure exactly what the rules say, but tastes are tastes as you say... I would place the switch in the live line.

Perfect, of course, good observation. In my real connection I did cutting the living, rather "by convention" than "by function," since it works perfectly the same. What happens is that when I started to draw the colors I did not realize the position of the colors and they were as much in the cut of the energy to the Light of Alarm as the contactor that you comment with the cian color (by convention: Neutral) and between the 1st. Post and this did not seem to change them to not confuse This would be the scheme with the inversion of colors:   <<Nombre.bmp>>.

58 minutes ago, plonkster said:

I don't know too much about that, but I hope not. I have a contactor on my inverter's input wired to the Ziehl anti-islanding device, and that thing is permanently on. When it's quiet at night, you can hear it hum. Can't do it any other way either... you need it to drop out when the power fails.

You're essentially using a contactor to invert the signal. I can think of ways to do this solid-state (opto-coupler, TRIAC), but it would take some time to explain that, and frankly... this will work fine as it is

Okay. In fact the contactors 1 and 2 of the schematic are with the coils permanently energized until the conditions indicated in the 1st. post of this thread.
Sure that could be solved with Solid State Relays, is a possibility that I evaluated, but the volume that occupies the heatsink of these made me lead to use contactors.
I am also working on an "update" of the automation that I present in this Post with a relay plate managed by a software that I am designing that will allow me in case of a power cut of of the Grid at a time when the energy production solar is GREATER than the consumption of the HIGH LOADS line, it will not be cut by the Contactor 1 of the scheme.
As soon as I finish it and do the first tests I publish it ...

Nombre.bmp

[Barezzi]

.

[Barezzi]

On 26/09/2017 at 2:50 PM, Cef said:

I am also working on an "update" of the automation that I present in this Post with a relay plate managed by a software that I am designing that will allow me in case of a power cut of of the Grid at a time when the energy production solar is GREATER than the consumption of the HIGH LOADS line, it will not be cut by the Contactor 1 of the scheme.

I am very much interested in the highlighted. Any updates?

[Cef]

15 hours ago, Barezzi said:

I am very much interested in the highlighted. Any updates?

Hi @Barezzi

Yes. I call the system: Phoram.

The issue is that the System is made for certain type of Power Inverters. The most modern of our beloved Chinese cheap polyfunctional Power Inverters: Hybrid type.
Search the topic "Internet of things", post "Phoram is coming" and you will see some of the screens with approximately 25% of the Total Functionality of the System.
There you will see how to find a Link to the RS232 communication protocol on which I am doing my system.

When I finish with the functionalities that I want to add for these powers inverters, I will try, with the help and proof of you to adapt it to the Protocol of the Axpert and similar ones that are not hybrids.

The Relay Board that I am using is:

http://www.icstation.com/icstation-channel-icse014a-micro-switch-relay-module-upper-computer-control-board-p-5185.html

With it and the software I intend to solve Many problems and concerns of Advanced Users.
 

-Solution to have a single input of PV in the Current Inverter and 2 (two) Chains with Opposite Directions (Face East and Face West). I have not found in my searches for the WEB a solution for Users whose roofs do not face North (or South depending on the hemisphere) or as in my case that although I have 2 (two) PV inputs in my power inverter , in my house I have run out of space to place Solar Panels to the North. For this reason the idea is to place panels on the roofs to the east and west, which for the lower cost of solar panels today is even a better solution than installing expensive motorized tracking devices.
I found a way to Automatically obtain the best use of Solar Power even for asymmetric chains (of different rated power) or with different inclination angles.
 

- Automated Solution to the Problem of 2 (two) MPPT (Power Inverter and External MPPT Charger) connected to the same (only) PV chain, which share the same bank of batteries.
 

-Solution to what is consulted by you. And several other possible uses imaginable and not yet imagined of the RELAY according to the information of the parameters delivered by the Power inverter (and in a next version by the Victron BMV702).

I estimate in about 3 months at the latest to release this system free of charge that I already have in operation because I use the information obtained to obtain statistics that I have not found in any software.

 

 

 

[Barezzi]

Hello Cef,

Any update on your project?

[Cef]

En 12/06/2018 a las 9:31 AM, Barezzi dijo:

Hola Cef,

Cualquier actualización en su proyecto?

Hola @Barezzi,

Hi Barezzi, I've been a bit busy and I have not been able to spend too much time on the system.
Also as I am a man of my word in July I will put the Beta Version, which is the I have in use at the disposal of the Power Forum community.
 I have been more focused on giving a good number of features for what concerns "Real-time monitoring and statistics".
At the end of July then.

 

[Barezzi]

July it is, fingers crossed!

[desiji]

On 2017/07/01 at 5:23 PM, Cef said:

Yes plonky  and thanks for your observation , the bypass switch is critical. I did not add it in the schematic since the purpose of it was to show only the use of contactors and Relay of the BMV702 and I did not want to complicate it with the complete scheme of my installation that includes devices of protection against lightning surges of measurement of imported energy And exported, reading, signaling, etc.

Good, i show a photograph of the By Pass switch (red key) from one of my boards.
The switch in question allows you not only to perform maintenance, but also must be there and your family should know it because if you are traveling or outside the house and the current Inverter is burned, it enters into fault condition or any other disaster that leaves your home without power, any member of your family can turn it to reestablish the service as if it had never done a solar installation.
If any member of the forum needs to know the wiring of the same, let me know and upload a picture of the connection scheme of the same.

 

can you send me the schematics of the whole installtion realy interested.

Thanks in advance

[Dan B]

I am interested in doing something similar but I have a complicated problem. My current situation is like the schematic below. The reason for this is that my house is 2 stories tall. The solar is on the roof along with the outdoor end of the aircon. The house is brick so we can't just run new cables. Even adding outdoor conduits is nearly impossible because the main breaker panel is in the center of the bottom floor. So with this setup, the same cables used to power the aircon are used to bring the power generated from the solar down to the main breaker and out to the grid (if there's excess). The problem is that when the main goes out, we have no power at all.

It looks like in the systems you all have posted here, you are still able to put the inverter between the grid and the main breaker panel, but that is not an option for me.

I was thinking of doing some sort of auto switch where when the main goes out, a switch at point B would automatically disconnect the main. Then a new hybrid inverter (replacing the old) would switch with an automatic switch at point B. That would disconnect the house wiring from the main inverter output to the UPS or EPS output. I like the idea of wiring a light as an alarm to know when this happens.

The only problem I can see with this is that when the main comes back, I couldn't switch B back to the grid until A is first switched back to grid side of the inverter. But I'm thinking a small signal cable or two could fit in the existing conduit to make the switches work in the correct order. I am a little worried that the main breaker is in a brick wall and it wouldn't be too easy to put a switch between the main and the rails in the box, but i'm sure i can find an electrician with some ideas.

Is this possible? Am i missing something?

A little extra background: I live in the middle of the jungle and the power grid isn't too reliable. My wife and I work during the day from this house with various computers and equipment. Right now we have our network on a big UPS that will work for a few days but our computers and screens won't. We want those to run on the solar if the grid goes out, with maybe just a couple batteries, not enough to run the whole house on for a long time. We only need it during the day, and it's usually sunny. The power goes out frequently but not usually for more than just a day or two. The computers are all too far apart to put on their own UPS circuit, so we would rather just power the whole house and turn off our aircons if we need to. We also have an underground cistern with a water pump, so without power we also have no water.

My current setup diagram: