Dry contact signals - Axpert Inverters

[VaughanT]

Greetings - I''ve recently installed an Axpert 3kVA (PF=1) inverter as an off-grid backup power solution and have no issues with it. I noted that Voltronic updated the firmware to provide a dry contact closure (for example to pull-in an external relay for bonding the neutral earth together, or providing external telemetry signals (via menu 38). I've noted that on two units of the same vintage (3 and 5kVA capacity, circa 2015 ), this feature does not exist. Is it possible to do a firmware update to address this ? I need a means to drive an external indication that shows the inverter output is 'on' - One could provide a 230V relay monitoring the incoming AC supply - but I reason that the inverter is already providing this function internally. 

Inputs appreciated. 

Vaughan

[0 |>\/\/3|<|<3Я]

On 2019/01/30 at 1:00 PM, VaughanT said:

Greetings - I''ve recently installed an Axpert 3kVA (PF=1) inverter as an off-grid backup power solution and have no issues with it. I noted that Voltronic updated the firmware to provide a dry contact closure (for example to pull-in an external relay for bonding the neutral earth together, or providing external telemetry signals (via menu 38). I've noted that on two units of the same vintage (3 and 5kVA capacity, circa 2015 ), this feature does not exist. Is it possible to do a firmware update to address this ? I need a means to drive an external indication that shows the inverter output is 'on' - One could provide a 230V relay monitoring the incoming AC supply - but I reason that the inverter is already providing this function internally. 

Inputs appreciated. 

Vaughan

Hi Vaughan. I'm also interested in such a solution. Want to connect a light in a remote part of the house to indicate when we're running on battery power. This to prevent the use of heating appliances during such time, which is easy when the cutover is seamless - people don't know that we've lost the Eskom feed.

Would one be able to use the dry contacts from the Axpert King to connect a wire to a globe fitting? Would then want the globe to be illuminated when running on battery power. I'm clearly not an electrician

Edited March 12, 2020 by 0 |>\/\/3|<|<3Я

[Coulomb]

25 minutes ago, 0 |>\/\/3|<|<3Я said:

Would one be able to use the dry contacts from the Axpert King to connect a wire to a globe fitting?

Certainly.

Quote

Would then want the globe to be illuminated when running on battery power.

I'm not sure it will do what you want, not being familiar with the Kings. If you use SUB or SBU as your output source priority (seems likely), then perhaps you can put a really high voltage in setting 12, so it will always come on when in battery mode. But I don't really follow what happens when a King "switches back to utility source"; is this bypass mode, or ordinary line mode where you want to be anyway (in a King, because it's double conversion)? Other King owners may be able to help here.

For the actual dry contact connection, I'd use a small 3 V or 5 V plugpack, an LED light (preferably an industrial type with a decent bezel and diffuser) and a current limiting resistor. Wire them all in series, with care for the polarity of the LED and plugpack. Use the C and NO (Common and Normally Open) dry contacts; ignore the NC (Normally Closed) one.

Or perhaps instead of a red light saying "don't use the heating devices now", you could have a green one that says "it's safe to use the heating devices now". That will save a smidge of power or the LED when the battery is running. It's also fail safe in case the LED blows, but maybe you'd habituate to the LED always being on, and not notice when it goes off. If you wanted this behaviour, you would use the NC terminal and ignore the NO terminal. 

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2 hours ago, Coulomb said:

Or perhaps instead of a red light saying "don't use the heating devices now", you could have a green one that says "it's safe to use the heating devices now". That will save a smidge of power or the LED when the battery is running. It's also fail safe in case the LED blows, but maybe you'd habituate to the LED always being on, and not notice when it goes off. If you wanted this behaviour, you would use the NC terminal and ignore the NO terminal. 

Thanks for the information @Coulomb, and this suggestion makes sense. Was thinking of conserving the power when we are not being shed, but soon we may be on batteries more than on the utility.

Don't know enough about the electrical avenue to "use a small 3 V or 5 V plugpack, an LED light (preferably an industrial type with a decent bezel and diffuser) and a current limiting resistor". Was hoping to connect a core electrical cable to the inverter on the one end and to a light socket on the other end and then have the light either on or off from current sent by the inverter, based on the state of the inverter, e.g. running from batteries or mains 

[SOLARWIND]

On 2020/03/12 at 12:08 PM, 0 |>\/\/3|<|<3Я said:

Hi Vaughan. I'm also interested in such a solution. Want to connect a light in a remote part of the house to indicate when we're running on battery power. This to prevent the use of heating appliances during such time, which is easy when the cutover is seamless - people don't know that we've lost the Eskom feed.

Would one be able to use the dry contacts from the Axpert King to connect a wire to a globe fitting? Would then want the globe to be illuminated when running on battery power. I'm clearly not an electrician

 

[SOLARWIND]

A very simple way to get the same result, would be to install a simple mains operated relay and use the N.C. contact on it. Then use inverter power in series with this contact to supply your remote indicator or whatever. 

[Coulomb]

7 hours ago, SOLARWIND said:

A very simple way to get the same result,

Good idea. But even easier would be to get a green indicator wired to the grid AC. If the green indicator is off, don't use the heating appliances. No need even for a relay then.

I don't like the idea of 230 V on the tiny dry contact relay. It's rated for 250 VAC @ 3 A, but I'd prefer to see it used only for extra low voltage applications.

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17 minutes ago, Coulomb said:

But even easier would be to get a green indicator wired to the grid AC. If the green indicator is off, don't use the heating appliances. No need even for a relay then.

Thanks for all the great input folks. I think this suggestion makes the most sense.

[MarinusW]

Hi and apologies if I am reopening a subject but I am investigating the option to use the dry contacts to trigger my SMS unit to inform me when grid power is down. So Dry Contacts are ideal. However the outputs of the inverter manual as indicated in this thread is somewhat confusing - well to me anyway. So I just want to know when the grid power is down. My inverter is set to first use Solar then utility and then batteries.  From the Close and open combinations quoted you might have a false reading when your inverter uses power form grid during normal operations (in my case) when Solar is not sufficient). Am I correct or am I missing something? I hope my question makes sense of course. 

[Coulomb]

4 hours ago, MarinusW said:

I am investigating the option to use the dry contacts to trigger my SMS unit to inform me when grid power is down. So Dry Contacts are ideal. However...

The problem is that the dry contacts are not designed for this; they were originally designed for a battery low warning. They can with some models be used to tell when the inverter is in battery mode (so you can operate an AC-out neutral to earth relay; setting 38). Neither of these is what your want.

As indicated above, something that operates on utility power (a lamp or 230 V relay) is the natural way to do it.

[MarinusW]

33 minutes ago, Coulomb said:

The problem is that the dry contacts are not designed for this; they were originally designed for a battery low warning. They can with some models be used to tell when the inverter is in battery mode (so you can operate an AC-out neutral to earth relay; setting 38). Neither of these is what your want.

As indicated above, something that operates on utility power (a lamp or 230 V relay) is the natural way to do it.

Thanks for the response.  

I actually did a few tests today and realized the same. With Utility down there is no change in the state of NC or NO. So what you have indicated is unfortunately 100% correct. 

It seems I will have to have an outlet installed that is connected to the same line as the Geyser and Stove that is always connected to the utility line and use a relay to give me a dry contact signal for NC or NO and the change in state. Not the easiest route.

Thanks again. 

[Coulomb]

12 minutes ago, MarinusW said:

It seems I will have to have an outlet installed

I would think you (or more likely your electrician) could install a DIN mount relay in the DB that has the geyser and stove. That seems a lot less work than installing an outlet, but then you'd have to get the relay contact wires to where they need to go. 

[MarinusW]

True but having a separate outlet will also assist me to run tools in my garage which is currently overloading the inverter at times and is not required during backup situations. Also having an outlet makes me feel "safer" as the relay circuit I have will not be in the DB. Luckily the installation is in my Sub DB in the garage so I have done most of the work for the separate outlet and just need to connect it in the DB. Was just hoping using the dry contacts would be more elegant. 

[Pieke]

Woud it be possible to use the dry contacts to change automaticaly between output inverters and utility when battery is low? When battery is low dry contact will trigger nc relais to cut current output and this triggers automatic dual power control switch to go to utility. 

[Coulomb]

But the Axpert does this automatically, if wired correctly.