Schneider xw pro 6848 not powering up with eg4 lithium battery

[Shimmy]

We are running this under oscilloscope, the problem we face to be clear is that a new XW pro in our shop with the exact batteries (we took them back from @Koldsimer) with the exact same schneider firmware runs just fine off of 2 5000w packs, so we can see that voltage reacts to this but the levels in our shop will not represent failure of the unit.

we are collaborating directly with Eric at Schneider about this now, trying to get a categorical assurance relative to their circuit that we are in the clear

That is why it is really important to at least have the user be able to log some information for you. I would be very curious what happens at the low end of the operating temperature range and if that was not part of the problem. If this whole thread is bad press for SS, at least something useful could have been learned from it.

Oh well, hindsight 20-20 and all that.

 

[Mahendra Gomanie]

I hate to bring up old statements again.
But I think most of the users had other batteries that were used to start up these inverter and which these batteries did start up the inverters .
The point is that there is something that is causing start up issues either with the area ,batch of the batteries or some other factor.

 

[Mahendra Gomanie]

I have not shut down the system as yet so I can't take any data or videos as yet.
Will do when I can

 

[Shimmy]

...there is something that is causing start up issues either with the area ,batch of the batteries or some other factor.

Agree, but most failure modes are a combination of factors. If it can't be recreated reliably (or documented in a way that there is sufficient information) then it cannot be solved. The question is what commonalities did people with failures have; there has not been enough data provided to help determine that.

 

[robby]

My guess is it’s built in and I’m screwed, I’ve actually given up on trying to figure it out. It’s simple it doesn’t work, now the question is what if anything SS is willing to do.

I can't keep track of this thread any longer. Did they change your battery or do anything for you?

 

[Sierra Nevada]

I purchased 3 eg4 200 ah 24 volt batteries from Signature Solar and installed them 2 weeks ago I run a old Trace SW4024 that works great.
I have to precharge the batteries with my solar before the inverter will come on. George

 

[robby]

I purchased 3 eg4 200 ah 24 volt batteries from Signature Solar and installed them 2 weeks ago I run a old Trace SW4024 that works great.
I have to precharge the batteries with my solar before the inverter will come on. George

Are you saying that without Solar the Inverter will not start?

 

[Mahendra Gomanie]

Are you saying that without Solar the Inverter will not start?

I guess that's what he is saying

That's what we have all been saying

 

[SignatureSolarJames]

I purchased 3 eg4 200 ah 24 volt batteries from Signature Solar and installed them 2 weeks ago I run a old Trace SW4024 that works great.
I have to precharge the batteries with my solar before the inverter will come on. George

@Sierra Nevada It's been a while since I've worked with a Trace if you can post a video of your scenario that would be really cool to see

 

[Sierra Nevada]

@Sierra Nevada It's been a while since I've worked with a Trace if you can post a video of your scenario that would be really cool to see

Camera is mounted on the plywood so I can monitor voltage off inverter. George

 

[RCinFLA]

Xantrex XW model, DC input capacitance is about 27,000 uF with series resistance ESR of about 3.5 milliohms.
32 caps in parallel, Nichicon 820 uF +/-20%, 100 vdc, ESR approximately 100 milliohms each. The use of so many caps in parallel gives the XW a lower net ESR than most inverters. This makes initial battery connect surge current greater.

For comparison, a typical 5 to 6 kW 48v Chinese HF inverter has four 3,300 uF 80vdc to 63vdc, ESR approx. 40 to 80 milliohms each, in parallel for a total of 13,500 uF at 10 to 20 milliohm ESR. Hard to predict quality of caps used and how much PCB resistance there is between caps and DC input terminals.

Low frequency inverters typically have greater battery line capacitance than high frequency inverters due to LF inverter running input switching frequency lower (6-8 kHz) than HF inverters (18-25 kHz). Capacitors are for PWM high frequency digital switching currents of DC input.

Battery cables and circuit breaker adds most of extra series resistance. 10 foot pair of #0/1 gauge adds about 2 milliohms. Typical high current DC breaker has 3 to 5 milliohms of series resistance. Then add on BMS resistance + bus bar/connection resistance + wire lug resistance + battery internal resistance.

In their response to complain video, they sort of cheated by using a long, relatively smaller gauge cable, to connect to inverter. For design margin demonstration they should use no more than four foot length pair of 4/0 battery cable.

Too much resistance on lines to batteries increases 120 Hz ripple voltage (for 60 Hz sinewave inverter) impressed on these input capacitors which causes internal heating of capacitors due to their ESR at 120 Hz. This internal heating degrades capacitors. (bloated domed tops of caps)

 

[Sierra Nevada]

Are you saying that without Solar the Inverter will not start?

Robby,. It will not start without help from my solar. George

 

[Hedges]

It is simply a precharge problem.
You just need a way to get inverter capacitors precharged prior to hard-connecting lithium battery.

Solar works when the sun is shining.
Resistor (possibly with added capacitor or resistive load) should get lithium battery to accomplish precharging. Sudden current demand from inverter could clobber that, but PV worked for you.
A spare bank of old lead-acid car batteries could do it if sun isn't out.

Would be nice to have the feature built into battery/BMS, and they've tried with some models, but some differences between inverters (and battery models) means it doesn't always work. A bunch of settable parameters for the precharge could solve most problems.

My suggestions have included using about 50' of 12 awg romex, out one wire and back the other, as a precharge resistor. Suitable length will limit max current to under BMS limit during precharge, and still allow considerable amperage if inverter starts powering loads (for a short time until wire overheats, need to close switch to "on" position shortly afterwards.)

 

[jyoung1]

Has sig solar tried to adjust the precharge time on their BMS? They could possibly adjust precharge time and use the xw pro in their shop to replicate the issue people are seeing. This thread is too long for me to go back and read if this was done.

 

[Solar Guy Richard]

Has sig solar tried to adjust the precharge time on their BMS? They could possibly adjust precharge time and use the xw pro in their shop to replicate the issue people are seeing. This thread is too long for me to go back and read if this was done.

We definitely did. In fact, we extended it and shortened it to extremes to try and duplicate this issue. In the end, the batteries were returned and they worked immediately with our in house model that was identical to the users.

 

[Koldsimer]

We definitely did. In fact, we extended it and shortened it to extremes to try and duplicate this issue. In the end, the batteries were returned and they worked immediately with our in house model that was identical to the users.

It's like you still don't understand the problem. Everybody gets that they work on your inverter. Yet here is another user that can't get them to start his inverter without the help of his solar charge controllers.

You guys never made a single change to the bms on my batteries while i had them. We spent hours and hours on the phone, on multiple days with multiple techs and after two months, you guys still couldn't figure out what changes to even try. Pathetic.

You guys should hire @Hedges , @RCinFLA or @robby or one of the others that have told you how to fix this issue.

 

[Solar Guy Richard]

It's like you still don't understand the problem. Everybody gets that they work on your inverter. Yet here is another user that can't get them to start his inverter without the help of his solar charge controllers.

You guys never made a single change to the bms on my batteries while i had them. We spent hours and hours on the phone, on multiple days with multiple techs and after two months, you guys still couldn't figure out what changes to even try. Pathetic.

You guys should hire @Hedges , @RCinFLA or @robby or one of the others that have told you how to fix this issue.

I was simply answering his question. He specifically stated "Has sig solar tried to adjust the precharge time on their BMS? They could possibly adjust precharge time and use the xw pro in their shop to replicate the issue people are seeing." I quite literally answered his question and provided the information relevant to his specific question.

Are you mad I simply answered his question asking if we extended the precharge time on the xw pro in our shop telling him that we did in fact do this and it didn't help duplicate the problem? We 100% get the problem - specific users have specific inverters (not brand wide or even model wide or firmware wide) that require additional DC power to precharge and not go into a restart loop resulting in a fault. Knowing the why doesn't help fix the issue with a long term solution for specific users when 99% of people, with the exact same inverter brand, model, and firmware version, don't seem to have issues. So the real question is, what is it about these specific users and their specific inverter that is different than the other 99% of users with the exact same machine. This is an issue we are still researching and troubleshooting, and are in fact in direct communication with multiple inverter manufacturers at this point directly trying to see if we can come up with a solution.

 

[400bird]

This should not be this difficult.

Get a project box, push button, a couple glands, 1-4 ohm resistors (1 ohm for 12 volt batteries, 4 ohm for 48 volt batteries) fuse holder, etc. Built an external precharge system.

Maybe Sig should offer this for those that have precharge difficulty?
Or at least offer a warning that a few experience issues and have a simple plan outlined?
Or maybe those that are installing batteries and inverters should be willing...

I assembled my battery from an EV pack and don't have a horse in this race

 

[Shimmy]

I was simply answering his question.

The thing is that nobody that is reading this topic believes SignatureSolar has a) identified the problem; b) baselined the nature of the XW-Pro pre-charge characteristics; or c) solved it for the next person that has an issue. As a potential customer who intends to use an XW-Pro, I still don't really get if the external pre-charge arrangement would do the trick if I encounter problems... or if there won't be enough voltage to the inverter as it begins startup.

Maybe you guys don't have the lab bench stocked with what you would need to make it happen, but if you want to cater to the DIY market and not get your hands dirty troubleshooting on-site you are going to need that equipment. For me, the issue is shipping is going to be extremely expensive and if it doesn't work that is money down the drain which would make a system like SimpliPhi much more competitive.

(If you want to replicate @Koldsimer's specific situation properly I am guessing you need to put the batteries in a cold box around 32F.)

 

[Koldsimer]

I was simply answering his question. He specifically stated "Has sig solar tried to adjust the precharge time on their BMS? They could possibly adjust precharge time and use the xw pro in their shop to replicate the issue people are seeing." I quite literally answered his question and provided the information relevant to his specific question.

Are you mad I simply answered his question asking if we extended the precharge time on the xw pro in our shop telling him that we did in fact do this and it didn't help duplicate the problem? We 100% get the problem - specific users have specific inverters (not brand wide or even model wide or firmware wide) that require additional DC power to precharge and not go into a restart loop resulting in a fault.

Knowing the why doesn't help fix the issue with a long term solution for specific users when 99% of people, with the exact same inverter brand, model, and firmware version, don't seem to have issues. So the real question is, what is it about these specific users and their specific inverter that is different than the other 99% of users with the exact same machine. This is an issue we are still researching and troubleshooting, and are in fact in direct communication with multiple inverter manufacturers at this point directly trying to see if we can come up with a solution.

I'm not mad, just disappointed that you guys are so incompetent. Knowing the why would in fact fix the problem but Signature is fixated on making adjustments in house to try and get their system to not work rather than addressing the users that have issues. I'll say it again and again- you guys should have been smart enough to recognize the golden opportunity to get a grasp of this problem with my system. I'm right down the road from you guys. You didn't, likely because you thought i was doing something wrong- even though 3 other types of batteries worked with zero issues. Here we are five months later and Signature appears to be no closer to having an answer. Pathetic.