Schneider xw pro 6848 not powering up with eg4 lithium battery

[Koldsimer]

Try cleaning the busbar and make sure the cables are tightly bolted to the busbar. Could be some type of coating on the copper. Also saw a video where the busbar connection stripped out and had to be bolted. I think David Poz has that video.

Did that exactly. In fact since my 4/0 cables from the inverter had been hooked to fla's for some time, i made sure they were free of any corrosion with a wire wheel and a light metal file. Bolts are tight.

 

[MrM1]

Keep us posted. I'll be interested to see what sig solar says

 

[Koldsimer]

Keep us posted. I'll be interested to see what sig solar says

Will do for sure. Man i hope they can get these working.

 

[Koldsimer]

I got into my inverters fault and warning log and found that over the last several days i have about 5 of the warnings w48- dc under voltage. I believe this is happening every time i am trying to connect with the lithiums. I am also getting w68-transformer over temperature and faults f45-capacitor over temperature and f68- transformer over temperature. I believe these are popping up every time i try to turn on the system. Unfortunately, i cannot assign an accurate time or date because the system loses the time/date every time it is shut completely off. I do however show an accurate, and completely unrelated warning from 12/26/21, before i attempted to connect the eg4's and the rest of the warnings/faults come after that event so i know they are related to trying to power the system with the eg4's.

I'm going to clear all faults and warnings and attempt to power system up with just one eg4 battery and see what happens. If it doesn't work and i get similar results, i will check inverter for new faults/warnings.

 

[MrM1]

I'd still like probably try 2 xs, each time with a different battery

 

[Bluedog225]

Hope it works out. The only thing I could think of was one of the batteries failing under load.

Hope the seller has gives good customer service, though this week might be tough.

 

[SpongeboB Sinewave]

Guessing here but maybe the eg4 lifepower BMS is momentarily opening up due to over-current and so checking to see if the instantaneous battery terminal voltage is dropping might be something to check.

Some volt meters have a minimum voltage feature that, if fast enough, could catch the drop in voltage.

I would think that the pre-charge circuit should help this but the issue might go beyond charging of the capacitors.

boB

 

[Koldsimer]

Guessing here but maybe the eg4 lifepower BMS is momentarily opening up due to over-current and so checking to see if the instantaneous battery terminal voltage is dropping might be something to check.

Some volt meters have a minimum voltage feature that, if fast enough, could catch the drop in voltage.

I would think that the pre-charge circuit should help this but the issue might go beyond charging of the capacitors.

boB

I'm thinking that would explain my dc low voltage warnings from the schneider. That threshold is set at 44v iirc. Why nobody else has this issue.....?

 

[Koldsimer]

Signature Solar suggests i keep my charge controllers on to power the inverter before i cut dc and swap batteries. I always thought this could be a problem for the inverter?

 

[SpongeboB Sinewave]

I'm thinking that would explain my dc low voltage warnings from the schneider. That threshold is set at 44v iirc. Why nobody else has this issue.....?

Guessing again that it would have to do with the BMS over-currenting and turning the battery off momentarily and then turning back on after the inrush has stopped. As long as the capacitors don't charge up, which won't happen if the BMS shuts the batteries off, this might happen.

I did read the other responses but I'm not sure if I saw that your exact configuration has been replicated.

I don't suppose you have an oscilloscope handy ? That would show you for sure what the battery voltage is doing.

Otherwise I would just try a resistor across the switch but that may not always work because the higher source resistance could also drop the battery voltage as seen by the inverter as soon as it turns on.

So, the resistor value would want to be just high enough to keep the BMS from turning off but low enough to keep the inverter happy and on with no loads until you flip the battery breaker to ON and short out the resistor.

Probably low R value like RCAinFLA said but not sure of the optimum R value.

It may also be that the BMS may not allow the Schneider XW to run large-ish surge loads for the same over current reason.

But I could be completely off here. This is the first thing I think of other than just a bad connection between eg4 and XW inverter.

 

[SpongeboB Sinewave]

Signature Solar suggests i keep my charge controllers on to power the inverter before i cut dc and swap batteries. I always thought this could be a problem for the inverter?

That should work !

The only caveat with doing this is that when an MPPT charge controller has a high input voltage, abrupt connection of its output to the inverter battery capacitors can cause a big surge of current and hurt some controllers. This is why it is best, if possible, to connect an MPPT CC electrically close to the battery terminals rather than too close to the inverter battery terminals so that any surges are not from the inverter capacitors or inverter surge currents but rather from the battery terminals.

 

[Koldsimer]

That should work !

The only caveat with doing this is that when an MPPT charge controller has a high input voltage, abrupt connection of its output to the inverter battery capacitors can cause a big surge of current and hurt some controllers. This is why it is best, if possible, to connect an MPPT CC electrically close to the battery terminals rather than too close to the inverter battery terminals so that any surges are not from the inverter capacitors or inverter surge currents but rather from the battery terminals.

Thanks for all the ideas and information. The folks at Schneider and unbound solar say to definitely not do this. The schneider tech said it could be instantly catastrophic and really mess up my inverter. I still have lots of xmas leftovers in the fridge i can't afford to lose! All this is so far over my head, i'm lost.

I tend to think the bms suggestions you made are the root of this problem. From the run light indicating they are dishcharging when not connected to any load to the fact the alarm light comes on when they are attempting to power up, i think the bms is at fault somehow.

 

[Bluedog225]

Sorry you have to go through this. Sounds like a real headache.

It does lean me towards dumber batteries if I go this route. Like new cars, some of this stuff just gets in the way.

 

[MrM1]

Like new cars, some of this stuff just gets in the way.

No Doubt. That is one of the first things I do when I drive my wife's car on long trips. Go into the settings and turn all that buzzing, vibrating, honking, blinking crap off. It just messes with my "PTSD" which I do not need in heavy city traffic

 

[Koldsimer]

Sorry you have to go through this. Sounds like a real headache.

It does lean me towards dumber batteries if I go this route. Like new cars, some of this stuff just gets in the way.

Thanks... it's been a really frustrating ordeal.

LOL it's why i exclusively drive 73-91 chevy/gmc's.

 

[SpongeboB Sinewave]

Thanks for all the ideas and information. The folks at Schneider and unbound solar say to definitely not do this. The schneider tech said it could be instantly catastrophic and really mess up my inverter. I still have lots of xmas leftovers in the fridge i can't afford to lose! All this is so far over my head, i'm lost.

Not sure why this should be a problem as long a the CC is able to keep the battery voltage below its maximum rating and above LBCO voltage ?

I suppose if the AC loads change too much, the CC and solar cannot keep the AC output regulation steady, you might run into problems but it shouldn't hurt the inverter ? It isn't like this hasn't been done before. Just have to make sure the battery voltage is within a range and battery ripple current isn't so high that it ages the capacitors too fast.

But how do you think a hybrid inverter--solar controller works ?..... Except those usually run the solar output voltage at the inverter link rail voltage (hundreds of volts). They still have ripple current but it is lower than at say, 48V.

Having said this, it is definitely better to use batteries.

I tend to think the bms suggestions you made are the root of this problem. From the run light indicating they are dishcharging when not connected to any load to the fact the alarm light comes on when they are attempting to power up, i think the bms is at fault somehow.

Yeah, I think that might be it. You might be able to parallel a matched voltage but smaller lead acid battery to handle the surge.

If others have had this combination of products work before, then maybe your eg4 BMS is a lemon and you need another one. Lemon meaning the over current might be too sensitive.

boB

 

[Koldsimer]

Not sure why this should be a problem as long a the CC is able to keep the battery voltage below its maximum rating and above LBCO voltage ?

I suppose if the AC loads change too much, the CC and solar cannot keep the AC output regulation steady, you might run into problems but it shouldn't hurt the inverter ? It isn't like this hasn't been done before. Just have to make sure the battery voltage is within a range and battery ripple current isn't so high that it ages the capacitors too fast.

But how do you think a hybrid inverter--solar controller works ?..... Except those usually run the solar output voltage at the inverter link rail voltage (hundreds of volts). They still have ripple current but it is lower than at say, 48V.

Having said this, it is definitely better to use batteries.

Can i just throw all the breakers in my panel off to eliminate any load there? That should help the cc not see any surges, right? If i set absorb and float at say 55v and do this on a day with decent sun, they should be able to keep my inverter powered? I thought the folks at Schneider said the xw must have dedicated and separate battery power to function properly? Thanks

Yeah, I think that might be it. You might be able to parallel a matched voltage but smaller lead acid battery to handle the surge.

If others have had this combination of products work before, then maybe your eg4 BMS is a lemon and you need another one. Lemon meaning the over current might be too sensitive.

boB

 

[SpongeboB Sinewave]

Can i just throw all the breakers in my panel off to eliminate any load there? That should help the cc not see any surges, right? If i set absorb and float at say 55v and do this on a day with decent sun, they should be able to keep my inverter powered? I thought the folks at Schneider said the xw must have dedicated and separate battery power to function properly? Thanks

Well, yes you should be able to do that. But the loads have to be turned on at some time. Just the inverter turning on and driving its 60Hz transformer for the first cycles can present a surge to the DC input some times.

I think you said that the inverter did not turn on long enough for the SCP to show anything. It needs to start up enough to do that at least. I can't remember if the SCP comes alive before the inverter's AC output ?

I would most likely try to understand why the system with the eg4 batteries are not working right.. You are going to need a battery.

What Schneider means by needing battery is that it is powered by the battery side of the inverter and not by the same grid input used for charging.

Most charge controllers work the same way... They are usually powered by the battery side and not the PV side.

boB

 

[JoeHam]

Have you tried turning off all AC loads on the inverter and then powering it up with one EG4 minus RS485 connection?

Eliminate as many variables as possible.

 

[Koldsimer]

Have you tried turning off all AC loads on the inverter and then powering it up with one EG4 minus RS485 connection?

Eliminate as many variables as possible.

I have tried to power up with just one eg4 with no success. I did not cut all ac loads, but the only real startup surge is the fridge. Also when i fire up the system with the fla's the inverter hums, fans spin and it takes a couple seconds for house ac loads to get power, so i'm pretty sure that's not what's messing with the eg4's.

At this point, I'll be receiving the insight home tool to update my firmware next monday. Im going to try that and see what happens. Hope fully signature solar will have some new information.

I know its not exactly apples to apples, but my dads system has the same exact inverter/cc combo with discover lithium batteries and i had zero issues commissioning his system- been running perfectly for 8 months now. I know the discover batteries communicate directly with the inverter but it still seems they would go through the same start up inrush of current. He is running a much newer firmware version.