Schneider xw pro 6848 not powering up with eg4 lithium battery

[MrM1]

@Hedges Yes I agree in this new dawning age of LFP and DIY batteries, it does indeed seem that a pre-charge resistor somewhere in the set up is in order. And hats off to Sig Solar for trying to tackle this at the battery side level. And it would be nice if companies like Schneider would actually release a firmware that address this and initiates a slow start up, but I am not holding my breath.

But my question is this, specific to Schneider Inverters ~ the XW and SW. As @Koldsimer pointed out in post 1 of this thread ...

I turned the dc breaker on and the inverter began clicking and the fans began pulsing like the unit was trying to power up.

My assumption is the XW is "starved" for current or power and is pulsing because it is not getting enough to turn on? If I recall @Koldsimer did not get a low voltage fault at the XW because it never even got enough power to register a fault.

As I am seeing this same behavior when I press pre-charge resistor button before I turn on the main breaker to my SW, I have to wonder ...

1. how do we know the inverter is being pre-charged in this state? Should I attach a clamp meter to the resistor lead to see if and how long it takes for the current to drop to Zero (0) current?​

2. how long should I hold the button?​

3. does this pulsing and clicking do harm to the internals and / or contractors in the SW / XW inverters?​

I realized without a pre-charge, with LFP batteries unlike LA batteries, some bad stuff is bound to happen either to the MOSFETs of the BMS or the circuitry of the inverter. But is the Clicking and Fan Pulsing also doing harm?

 

[MrM1]

Right now I am using a 100w 50 Ohm, but I also have a 100w 10 Ohm resistor. Which would be better in this case? Which would pre-charge faster (sorry I do not know, I should probably, but I do not)

 

[Hedges]

Scope watching voltage at inverter would tell you something. Precharge resistor serves as current sense resistor.

Clicking with repeated power up attempts is dissipating power somewhere.
Some switching power supplies commit Hari-Kari under brownout conditions. Inverter may have those to power internal circuitry.

a 10 ohm resistor would power up faster.

My suggestion (for BMS without precharge system built in) is divide battery voltage (e.g. 50V) by maximum current spec (something like 100A or 200A), which gives a resistor value 0.5 ohm or 0.25 ohm. That means 50V into 0.5 ohm would draw 100A max. Use that for resistor.

A length of 12 awg or 10 awg Romex, with white and black wire joined by wire nut at one end, would be good. Some 10's to 100's of feet, a spool, would be 0.5 ohm, and power dissipation would be quite good. It can carry a massive current like 100A for a short period of time 1000A, sufficient to precharge capacitors and then power inverter. Connect this precharge resistor then close main switch.

I think inverter has 0.1F to 1.0F of capacitor (some would be less.) T = RC = 0.5 x 1.0 = 1/2 second to charge 1.0 F to within 1/e of battery voltage or about 2/3 of the way there. Six time constants, 3 seconds, gets within 2^6/3^6 = 0.09 of charged, 91% of the way there. (more if smaller capacitor)

Your 100 ohm resistor and 0.1 F would have 10 second time constant, a minute to reach 90%! And that's if no significant DC draw.
10 ohm resistor would have 1 second time constant, so 6 seconds to charge the smaller assumed 0.1 F capacitor. 60 second for 1.0 uF. 0.6 seconds for 0.01 F (10 mF, 10,000 uF)

If BMS has precharge circuit, that is likely decent performing for some range of inverter input capacitor. But not if inverter starts drawing current. In that case, having BMS precharge a supercap that is 10F or larger, then using Romex 0.5 ohm "resistor" to precharge inverter might work.

Bottom line, it take a low value resistor or inordinately long time with higher value resistor to charge typical large inverter input capacitor bank. And with any discrete resistor, it can't power inverter through the resistor, needs to be turned completely on.

 

[Koldsimer]

Just spoke with James and Ray at Signature. They are awaiting the Schneider xw 6848 and they are confident they can find a solution to make it work.

They aren't sure why this specific model inverter is having these issues but they say they will find out and offer a fix.

They also took care of my charger issue, and we addressed the issue with the rack and lack of cables with my batteries.

I feel better about the situation and am confident they will ultimately offer a solution that works.

 

[MrM1]

Just spoke with James and Ray at Signature. They are awaiting the Schneider xw 6848 and they are confident they can find a solution to make it work.

They aren't sure why this specific model inverter is having these issues but they say they will find out and offer a fix.

They also took care of my charger issue, and we addressed the issue with the rack and lack of cables with my batteries.

I feel better about the situation and am confident they will ultimately offer a solution that works.

Good to hear

 

[MrM1]

Scope watching voltage at inverter would tell you something. Precharge resistor serves as current sense resistor.

Clicking with repeated power up attempts is dissipating power somewhere.
Some switching power supplies commit Hari-Kari under brownout conditions. Inverter may have those to power internal circuitry.

a 10 ohm resistor would power up faster.

My suggestion (for BMS without precharge system built in) is divide battery voltage (e.g. 50V) by maximum current spec (something like 100A or 200A), which gives a resistor value 0.5 ohm or 0.25 ohm. That means 50V into 0.5 ohm would draw 100A max. Use that for resistor.

A length of 12 awg or 10 awg Romex, with white and black wire joined by wire nut at one end, would be good. Some 10's to 100's of feet, a spool, would be 0.5 ohm, and power dissipation would be quite good. It can carry a massive current like 100A for a short period of time 1000A, sufficient to precharge capacitors and then power inverter. Connect this precharge resistor then close main switch.

I think inverter has 0.1F to 1.0F of capacitor (some would be less.) T = RC = 0.5 x 1.0 = 1/2 second to charge 1.0 F to within 1/e of battery voltage or about 2/3 of the way there. Six time constants, 3 seconds, gets within 2^6/3^6 = 0.09 of charged, 91% of the way there. (more if smaller capacitor)

Your 100 ohm resistor and 0.1 F would have 10 second time constant, a minute to reach 90%! And that's if no significant DC draw.
10 ohm resistor would have 1 second time constant, so 6 seconds to charge the smaller assumed 0.1 F capacitor. 60 second for 1.0 uF. 0.6 seconds for 0.01 F (10 mF, 10,000 uF)

If BMS has precharge circuit, that is likely decent performing for some range of inverter input capacitor. But not if inverter starts drawing current. In that case, having BMS precharge a supercap that is 10F or larger, then using Romex 0.5 ohm "resistor" to precharge inverter might work.

Bottom line, it take a low value resistor or inordinately long time with higher value resistor to charge typical large inverter input capacitor bank. And with any discrete resistor, it can't power inverter through the resistor, needs to be turned completely on.

I'll replace it with a 0.2 Ohm

 

[Hedges]

50V/0.2 ohm = 250A

What is inverter drawing when it starts up into loads? Or does it start up with AC loads disconnected?
If 1000W draw, 1000W/50V = 20A
20A^2 x 0.2 ohm = 80W

Under such conditions, if your resistor is rated < 80W, it will overheat in some period of time.

Some resistors are "pulse rated", can take a brief hit. Others are not. We had a small 0402 resistor of low value sensing current to a 1/2 amp load. But when power was applied, there was an inrush of several amps (or was that 10's of amps?) for 10 microseconds. The resistor failed. A different pulse-rated resistor as replacement survived.

If your 0.2 ohm resistor is not rated 80W and it carries a precharge pulse of 20A ore more, it may not last.
This is why I suggested a length of copper. It would get hot eventually, but could handle moderate inverter operation for a period of time, as well as any precharge pulse.

edit:
50V system?
50V^2 / 0.2 ohm = 12500W
That is the pulse your resistor must withstand (12.5 kW)

 

[MrM1]

The resistor is rated for 100w and the system is 24v so with LFP it is 25.2vdc.

 

[gmbeihl]

FWIW, My old dual stacked Trace 4024 power panel powered up with a set of EG4-LL batteries without issues. I had the inverter loads bypassed and it came up in the "off" state. Glad I ordered the LL's at this point after reading through this...

 

[robby]

FWIW, My old dual stacked Trace 4024 power panel powered up with a set of EG4-LL batteries without issues. I had the inverter loads bypassed and it came up in the "off" state. Glad I ordered the LL's at this point after reading through this...

I have the LL also but I am not 100% sure that it is really any different except for the display.

 

[Mr-Sandman]

I think I read where Signature Solar said the EG4 LL has a different BMS than the LifePower4 with the same cells. It would be nice to know more about them. Seems like they either changed BMS on the LifePower4 for this last batch or at least they are configured differently.

 

[Quattrohead]

Try nichrome wire as found in old heating elements like HVAC units, that is what I use for heavy loads.
It makes a very durable resistor.

 

[robby]

I think I read where Signature Solar said the EG4 LL has a different BMS than the LifePower4 with the same cells. It would be nice to know more about them. Seems like they either changed BMS on the LifePower4 for this last batch or at least they are configured differently.

Are you comparing the older GyLL bateries or the Eg4 vs EG4 LL? I am pretty sure they said the Gyll had a different BMS but I assumed the both of the new EG4 models had the same BMS minus the LCD being hooked up. I could be wrong.

 

[merritt2828]

I received a single eg4 (wanted to test just one first), magnum 4448, classic 150, off grid and had the same boot up issue last week. Connected to BMS, alarm was for overcurrent. Suspected inrush problem, so for S&G, I connected it to my 48v "golf cart". Same result - can't even handle powering on its controller. Reconnected to off grid system and was able to power on using classic's output...while wondering what to do if the sun wasn't shining. It's worked fine (after working thru mistakes in the manual). I've been trying to figure out the ideal charge voltages and ran across this post. Thanks for letting me know I'm not alone and hopefully SS can provide a firmware update for the BMS. Jack rabbit, I'm afraid you're gonna have the same issue.
I'm also here until tomorrow afternoon if anyone would like me to troubleshoot anything for them.

 

[Mr-Sandman]

Are you comparing the older GyLL bateries or the Eg4 vs EG4 LL? I am pretty sure they said the Gyll had a different BMS but I assumed the both of the new EG4 models had the same BMS minus the LCD being hooked up. I could be wrong.

I'm comparing the EG4 LL (lcd) "currently shipping" with the EG4 LifePower (no lcd) "currently shipping". Let's ask them.
@SignatureSolarUS can you tell us which battery models of yours (past and current) share the same BMS? Are they ALL compatible with each other as far as communicating with each other?

 

[Jack Rabbit Off Grid]

T

I received a single eg4 (wanted to test just one first), magnum 4448, classic 150, off grid and had the same boot up issue last week. Connected to BMS, alarm was for overcurrent. Suspected inrush problem, so for S&G, I connected it to my 48v "golf cart". Same result - can't even handle powering on its controller. Reconnected to off grid system and was able to power on using classic's output...while wondering what to do if the sun wasn't shining. It's worked fine (after working thru mistakes in the manual). I've been trying to figure out the ideal charge voltages and ran across this post. Thanks for letting me know I'm not alone and hopefully SS can provide a firmware update for the BMS. Jack rabbit, I'm afraid you're gonna have the same issue.
I'm also here until tomorrow afternoon if anyone would like me to troubleshoot anything for them.

This don’t sound good.

Anyway I drove to my local FedEx terminal today to pickup my order. it made it from Texas to Bend Oregon with only one little hole in the rack box. Nothing big just scratched one panel a bit. On my way there I got a call from Old Dominion freight lines and my inverter/load center was sitting at there dock so I swung by and picked it up also.

I got the battery rack assembled and unboxed one battery and checked it out. It looks good and powered on like it’s supposed to. also has 50% charge and it’s cables. I’m not going to unbox anymore. Because if I can’t get the one to work why bother? I’ll get the inverter/load center installed this weekend and call Ray at Signature on Monday before I continue on. I was told they already have Magnums running on them so we will see.

 

[merritt2828]

T

This don’t sound good.

Anyway I drove to my local FedEx terminal today to pickup my order. it made it from Texas to Bend Oregon with only one little hole in the rack box. Nothing big just scratched one panel a bit. On my way there I got a call from Old Dominion freight lines and my inverter/load center was sitting at there dock so I swung by and picked it up also.

I got the battery rack assembled and unboxed one battery and checked it out. It looks good and powered on like it’s supposed to. also has 50% charge and it’s cables. I’m not going to unbox anymore. Because if I can’t get the one to work why bother? I’ll get the inverter/load center installed this weekend and call Ray at Signature on Monday before I continue on. I was told they already have Magnums running on them so we will see.

Yeah, let me know how it goes. Could be something with my setup, but I've been running with lead acid for 5 or 6 years now without this issue. And if it can't "boot up" my golf cart, it's hard to imagine it would work on most low frequency inverters.

 

[robby]

I'm comparing the EG4 LL (lcd) "currently shipping" with the EG4 LifePower (no lcd) "currently shipping". Let's ask them.
@SignatureSolarUS can you tell us which battery models of yours (past and current) share the same BMS? Are they ALL compatible with each other as far as communicating with each other?

I am confused, I always thought that the EG4 Lifepower (no LCD) the Gyll Lifepower and the EG4 LL (no lcd) where basically the same pack and they had just moved the terminals and breaker a bit and redid the branding. The BMS external connections and everything else look identical.

They even say this on there website: Link
12V 400AH Battery by EG4
GYLL HAS REBRANDED TO EG4. SAME GREAT BATTERY, DIFFERENT NAME.

So they have 4 models of battery? I assumed the first three on this list are the same with just a different look?

Gyll Lifepower
EG4 Lifepower (no lcd)
EG4 LL (no lcd)
EG4 LL (with LCD)

The EG4LL (with LCD) should be compatible with the other three, but it seems like it is not.
Are the first three all communication compatible?

 

[Mr-Sandman]

The EG4LL (with LCD) should be compatible with the other three, but it seems like it is not.
Are the first three all communication compatible?

@SignatureSolarUS will have to answer this, I don't think any of us knows and it doesn't seem to be documented anywhere.

 

[Jack Rabbit Off Grid]

I believe but not sure all other then the EG4 Lifepower4 are compatible. I also believe that they were trying to make the EG4 Lifepower4 an affordable simple alternative for the masses. Probably never thought they wouldn’t power up certain inverters. Just like the 6 battery rack I just received. It has no top nor a door. They are trying to keep the price down but have a quality product. If they are reading this. Please stock doors and tops for the people that would pay extra for them like me as an upgrade option.