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Schweitzer XW6848+ inverter Won't Drive AUX output port for Gen Start

MarkNiwot

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Jan 18, 2023
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San Luis Valley, Colorado
I have a new (to me) Schweitzer 6848 inverter (and the hundreds of pages of manuals) that will NOT seem to drive the AUX port pins to start a remote generator.

The manuals say pin 4, which I wired (two-wire start to Generac) is an open collector driver, capable of up to 30V Vcc. The controller has a pull-up to 5V, and all it takes to activate the generator is to turn on that driver (ie, pull the output low.) I can do that with a remote switch, which is how I'm having to run the backup generator now.

The menus allow multiple signal sources for that output (I've tried 'em all, and set the voltages, charge states, etc) -- SOC, low battery voltage (either) will suit my purpose, which is to turn on the generator when I get to the point I want the batteries to have help. But I simply can't make that pin change state (including the 'manual on' menu choice.)

I have concluded that EITHER - the inverter aux port isn't working right , OR
-- there's a TRICK hidden in there somewhere to activate/enable something that they aren't telling. Any ideas?


PS> There's (supposedly) a switched 12V output on pin 1 (both ref'd to pin3 ground) - but I can't make that switch either. It just stays at +12V.
 
If you can start your generator by closing a switch, couldn't you try driving a relay with the XW output?

To get more insights into this, you might go over to the NAWS Solar Electric Forum where switched outputs of the XW6848+ and the Insight Home/Facility Gateways are being discussed. A bit more information on your system would help to, what's connected to the XW and type of battery etc. Usually an Auto Generator Start module or other interface is used (BMS etc.) to issue generator start commands and not just an inverter switched output.

Dave Angelini there is a Schneider Guru. Perhaps not totally relevant but he mentioned that the Gateway's haven't fully implemented switch output / and digital input controls in their latest firmware yet - same might be true for the inverter itself. I don't have an XW+ (yet) to share any personal experiences but I'm trying to learn about them.

Is it possible that values such as the SOC and battery levels that drive the inverter switches are only provided to the Inverter on the Xanbus network from the battery monitor and the automatic generator start module (if connected)? After all the inverter's job is to invert and it would not "know" the battery SOC (as you say it would have access to the battery voltage, but the XW's only read battery voltage approximately as I've heard, thus the rationale for a more accurate battery monitor or SOC from the battery BMS in event of a Li battery). The inverter may have software on board that only works if the network state with those values is passed on from other equipment. Dave would know .....
 
I have a new (to me) Schweitzer 6848 inverter (and the hundreds of pages of manuals) that will NOT seem to drive the AUX port pins to start a remote generator.
Could you post exactly which model inverter you have? Its a Schneider, yes. There is only one Aux relay that can supply 12V, 250mA. The InsightHome device has at least 1 aux relay but I believe its a "dry contact" type. Not sure what you were referring to regarding pin 4, open collector?
The inverter has quite few options user menu options as far as being able to choose a suitable parameter to start the generator. I would think battery voltage would be a good choice. Usually a 2 wire gen start only needs dry contacts so you may need to use relay with a 12V coil to convert the inverter output to dry contact closure.
 
XW+ is the only other qualifier...
But the problem is that the 7 pin "Aux" connector on the bottom of the unit (the only such connector) has the output, pin 4, that is said to be configurable to trigger, active high or low, on a number of conditions. It will NOT. Nothing switches in response to the programmable menu options. (My intention would be to trigger on low battery voltage.)

The problem is that, regardless of menu selection, I can't get any AUX output to do anything. (including a manual "on").

And thanks, I'll take a look at that other forum and try to find Dave. I have a strong suspicion there's something "undocumented" in the firmware (or, perhaps, as you suggest, even non-existent. But it IS in the manual...)
 
XW+ is the only other qualifier...
But the problem is that the 7 pin "Aux" connector on the bottom of the unit (the only such connector) has the output, pin 4, that is said to be configurable to trigger, active high or low, on a number of conditions. It will NOT. Nothing switches in response to the programmable menu options. (My intention would be to trigger on low battery voltage.)

The problem is that, regardless of menu selection, I can't get any AUX output to do anything. (including a manual "on").

And thanks, I'll take a look at that other forum and try to find Dave. I have a strong suspicion there's something "undocumented" in the firmware (or, perhaps, as you suggest, even non-existent. But it IS in the manual...)
I'm using an XW+ to trigger a stand alone Bluetooth cell balancer based on voltage, works very reliably. In the user menu set up there is a choice of active low or active high and there may be another option to enable or disable the Aux. Give me a couple of minutes to check, will let you know.
 
There is no Aux enable/disable only Manual On, Manual Off or Automatic. You would want Automatic.
Next setting: Active High or Active Low. You would want Active High.
Trigger source: Low Voltage
Trigger Delay: Make sure the trigger delay is only a few seconds.
Low Voltage Set Point is when the Aux relay closes to start gen.
Low Voltage Set Clear is when the Aux relay reopens to stop the gen.
If the Aux relay is not working maybe its damaged? Its only rated for 250mA.

In my experience the Aux relay works exactly as described in the manual.
 
In my experience the Aux relay works exactly as described in the manual.
Yeah - the SCHNEIDER manual... ;)

Which is what I expected. But - mine simply doesn't. So - I'm beginning to suspect there's an output failure. Was hoping someone would tell me about a hidden footnote in some Tech Note that said you have to poke two other buttons on some submenu simultaneously while pulling your left ear...
 
But - mine simply doesn't.
Can you get the contacts to close/change state for any event? I seem to remember a few people having failures of the aux outputs 6-12 months ago. If they do close, does it work if you add an interposing (ice cube) relay between the aux and the generator wiring? Have you considered adding the Schneider generator control module?
 
Can you get the contacts to close/change state for any event? I seem to remember a few people having failures of the aux outputs 6-12 months ago. If they do close, does it work if you add an interposing (ice cube) relay between the aux and the generator wiring? Have you considered adding the Schneider generator control module?
No - the 'signal' will not activate for any event. Hence my questions here. Either it is bad, or there is an undocumented 'trick.'

As for "have I considered" spending half a grand for a simple relay - not for very long. Especially since it evidently wouldn't work either.
 
The inverter has a very comprehensive status page that is available through the Combox. I have attached screen shots from my inverter. If you look towards the bottom it will give the status or the Aux relay. If you can take a look at that status page it will tell you if the Inverter firmware/software "thinks" the Aux relay is On or Off. This would the first step in diagnosing the problem, if you can get the status page to show Aux relay in both the Off & On state.
Then step 2 is to test and find out if there is a control signal being sent to the Aux relay or SSR or BJT whatever it is. If yes then the relay is bad. If no then there is a problem somewhere on the PCB between the microcontroller and the relay.

In your Original Post you said the inverter was new to you which implies it may be previously owned and a few years old. Is it still under warranty? Not sure if you are comfortable with or have a voltmeter that would allow you to do some self diagnosis discussed above.
 

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