Schneider xw pro 6848 not powering up with eg4 lithium battery

[Mr-Sandman]

Well good deal. The batteries did their job and kept you from destroying them by charging while below freezing. 41 is pretty cold, I hope you have enough heat to keep your batteries from freezing on a regular basis.

 

[Jack Rabbit Off Grid]

We ran out for a minute. Give us a call and we can send some out for you.

I was under the impression that I had to have them so the batteries could communicate between each other. But after speaking with another one of your customers he explained they only work with GroWatt see no

Well good deal. The batteries did their job and kept you from destroying them by charging while below freezing. 41 is pretty cold, I hope you have enough heat to keep your batteries from freezing on a regular basis.

yes the utility shed is heated but even during the coldest nights it never gets below 39. I did turn on the heat when it got down to 0 a few weeks back. There is also a 500 gallon cistern tank in there. And when I fill it to the top the water coming from the well is in the 60’s so it heats it back up and holds a pretty steady temperature all the time.

 

[Solar Guy Richard]

41 deg in the shed and all 6 batteries are charging as the are supposed to.

I’m such an idiot! I’m so worried about another disaster to happen I’m thinking strait.

Moving off grid and building an entire homestead from scratch is way more work then I thought.

Glad to hear! As always feel free to message me or give us a call if you have any other questions.

 

[AlaskanNoob]

41 deg in the shed and all 6 batteries are charging as the are supposed to.

I’m such an idiot! I’m so worried about another disaster to happen I’m thinking strait.

Moving off grid and building an entire homestead from scratch is way more work then I thought.

I know exactly how you feel. So used to things not working and mini-disasters that you always jump to the worst conclusion and overlook the obvious. We've got a homestead in Alaska in the middle of nowhere, had our yurt destroyed by brown bears, lost a thousand bucks of freeze dried food to em too, and it's just one thing after another.

One day I got my six by six (on tracks) stuck on our two mile ATV trail to get to our place. Big mud hole, couldn't climb up out of it like I normally did. I jumped to the worst conclusion, called the wife to come get me and minutes later realized I didn't have 6x6 selected. I was in 2x6. No wonder the first tracks weren't getting me out of that hole. It took me a half an hour of trying to get out of the hole before I realized this.

Homestead life trains you to expect the worst. Glad your batteries are good to go!

 

[Koldsimer]

We are researching this issue very heavily to make sure our batteries work with as many inverters as possible. I can assure you we want our batteries to be the best and work for everyone!

@signaturesolarrichard @SignatureSolarRay

Any progress this week?

 

[Solar Guy Richard]

@signaturesolarrichard @SignatureSolarRay

Any progress this week?

Yes sir - if by progress you mean "Are you closer to an answer than before?"
Seriously though, we just received several of the inverters we had ordered and are still waiting on several more. I'm just seeing this at 10:37PM on Friday but I'll double check on Monday if this specific model was received yet or not.

 

[Koldsimer]

Just saw Wills video review of the SOK 48v rack mount battery. He mentioned a very specific starting procedure for the batteries pre-charge feature. He also mentions the bms is the same as the eg4. I wonder if there is a turn on procedure with the reset button that the eg4 lifepower requires that we are not aware of?

 

[Mr-Sandman]

Great question.
But Signature Solar has stated that the EG4 LL and EG4 LifePower4 do NOT share the same BMS...
I would think the SOK rack battery shares the same BMS as the EG4 LL, they both have a screen, etc...
I would like to know the proper way to power up my Inverter with the EG4 batteries. It worked just turning the breaker on the battery with the inverter connected. But I only did it once, been powered on since...

 

[MrM1]

I still wonder if it would power on the inverter using an external resistor to charge the inverter caps b4 turning on the inverter. Has any one tried that?

 

[JoeHam]

I still wonder if it would power on the inverter using an external resistor to charge the inverter caps b4 turning on the inverter. Has any one tried that?

I’ve wondered the same thing.

And since this is usually a one time event I would prefer a battery without all the precharge nonsense built in (like my old style GYLL) so I could just use a $2 resistor one time and get on with my life.

It seems the precharge circuitry might be more trouble than it’s worth ?

Just one opinion.

 

[Hedges]

But what happens after a low-battery disconnect?
Which ought to be avoided by BMS telling battery to stop drawing current.

(I agree though, I like simple and robust.)

 

[robby]

I’ve wondered the same thing.

And since this is usually a one time event I would prefer a battery without all the precharge nonsense built in (like my old style GYLL) so I could just use a $2 resistor one time and get on with my life.

It seems the precharge circuitry might be more trouble than it’s worth ?

Just one opinion.

I think Precharge resistors are fine but I just don't like the way it was implemented in the EG4. I appreciate the fact that they were trying to make something that was more automated but it just seems like it did not work out.

If you have not watched the new video that Will posted on the SOK 48v battery you might want to. The way they implemented it is so much better, it is unobtrusive to the operation of the Inverter. You have to press a button if you want it to start charging, if not just throw the switch and done you got full power.

I could kick myself for not waiting on that battery as it is much better build quality than the EG4 and a bonus is the fact that you can remove and replace individual cells and replace them easily. The kicker is that it cost the same price as what I paid for the EG4LL and it has basically the same display.

 

[SolarPrep]

50V/50 ohm = 1A, 50V^2/100 ohm = 25W, probably works fine for precharge.

Say 5V drop (leaving 45V to power inverter) divide by 50 ohm = 0.1A, 45V x 0.1A = 4.5W, not enough to keep inverter up with standby draw.
You'll need to close switch fast enough to supply inverter before it starts inverting.

Consider 100A, 50V. That's 0.5 ohms. 400A would be 0.125 ohms. Look for a piece of wire in that range, and heavy enough to carry a couple amps or more. That would precharge capacitor without exceeding BMS limit, and carry 100W or more of idle consumption. 12 awg is 0.16 ohms per 100'. Have a 100' or 250' coil of Romex? About 0.3 ohms or 0.75 ohms round trip. Put a wire nut on white & black at one end. use other end as precharge resistor. That should limit current to 75 or a couple hundred amps and power up the inverter.

Hedges: Would a heavier gauge of wire be better in this situation? Like 10g? Just asking out of curiosity.

 

[upnorthandpersonal]

I'm repeating myself here, but in my opinion, the capacitor pre-charge should be part of the inverter design. In the same way you don't put a soft-starter for the motor you're running on the inverter, but on the actual motor. The device that can cause the issue should do the mitigation of said issue. You can run a motor without soft-starter, just like you can an inverter without pre-charge if you take the precautions you would in either case, but I think this would be a good time for inverter manufacturers to start offering inverters with 'soft-start' capability built in. Doing it on the battery can lead to all kinds of weird compatibility issues and edge cases that cause the pre-charge to be completely ineffective.

 

[Mr-Sandman]

@upnorthandpersonal that makes sense, except in most cases with Lithum batteries with BMS, the Battery is what can't handle the inrush and is damaged if the inverter isn't pre-charged. So they are putting pre-chargers in them to try to protect their BMS and battery, not for the inverter necessarily.

 

[upnorthandpersonal]

@upnorthandpersonal that makes sense, except in most cases with Lithum batteries with BMS, the Battery is what can't handle the inrush and is damaged if the inverter isn't pre-charged. So they are putting pre-chargers in them to try to protect their BMS and battery, not for the inverter necessarily.

Yes, just like the inverter that won't be able to handle a motor with large inrush. The soft start goes on the motor even tough the motor won't break. Except in this case, it's a far more clear-cut and common problem.

 

[SolarPrep]

I think the problem with all this is that Signature Solar does not design and manufacturer their own BMS's. They may not be able to modify the surge over-current time and level. Please, Signature Solar, correct me if I am wrong. It is hard to say from their web site and videos how this all works

But if S.S. puts the BMS and battery system together, they may be able to mate up a BMS that has a higher instantaneous current limit rating.
I do not see a surge rating on their specs. Continuous discharge is, I think, 200 amps and recommended is 60 amps.

Charging a capacitor like these inverters use can draw hundreds of amps momentarily. Might be difficult to get that protection just right, and for all of these different inverters too. But, it must work. Some pre-charging can help but I don't think that one resistor value is going to work for all inverters out there.

https://upload.wikimedia.org/wikipedia/commons/1/1b/Capacitor_charging_Current_and_Voltage_Graph.png

And "Closed loop" inverter/charger to BMS is a great thing but I don't think it is something that can help with something like this. It might help to let the BMS what to expect though the next time it turns on ?

Nope, they don't make these, or even assemble them. They just unload containers of them, shipped from China.

 

[Hedges]

Hedges: Would a heavier gauge of wire be better in this situation? Like 10g? Just asking out of curiosity.

Sure, you could use any gauge, even 4/0 if long enough to provide the desired resistance.

I'm repeating myself here, but in my opinion, the capacitor pre-charge should be part of the inverter design. ... Doing it on the battery can lead to all kinds of weird compatibility issues and edge cases that cause the pre-charge to be completely ineffective.

All we need from the inverter is to not turn on immediately. Either manual precharge or BMS doing it, we want capacitors to reach near full voltage and then switch closed for low resistance before inverter starts sucking multiple amps.

The reason inverter can't easily do this is it doesn't have a controlled switch between DC input and capacitors. Some have a breaker built in, some do not.

BMS has FET or relay between cells and battery cables. Simply turning on FETs gradually so they present high resistance (limiting current) and burn off some heat due to voltage drop (as high as 48V or so) times current. Given enough time, that fully charges capacitors in inverter. Trouble is, inverter will likely draw some current for its internal circuitry, so FET (or separately switched precharge resistor) needs to handle that current. Definitely can't have inverter start producing AC until precharge complete and FET on hard or relay closed.

Best design would be BMS performs precharge and communicates to inverter saying when it is OK to turn on.

Specs for Sunny Island are 4W standby, 25W idle. (Of course, if AC loads present and motors being started, could be 11kW)

4W/48V = 83 mA. Sunny Island powers up in Standby, until you press and hold button to start.
25W/48V = 0.52A, this is what it would draw if AC loads were disconnected and inverter started the moment voltage appeared.
(Problem with other inverters is likely that they power up when DC appears.)

For this inverter, need to design for 83 mA.

Using a wire for precharge resistor, could be a length of telephone or LAN wire, enough for a few ohms or a fraction of an ohm.
That wouldn't be able to power inverter if it turned on before you closed the switch.
Using 12 awg or something larger, enough for about 0.5 ohms, could power inverter up to a few amps (couple hundred watts) with a few volts drop. If switch closed with a few amps and a few volts across it, small inrush. Best to close before that happens.
Don't use a coil of single wire, that is inductance. A coil of 2-wire cable is fine, with the two wires joined at end; current flows out one way through coil and back the other way, cancelling magnetic field and inductance.

 

[Mr-Sandman]

None of us knows how the EG4 battery pre-charge works exactly.
Signature Solar told us early in this thread it's timer based, but we don't know how long, how much pre-charge current is supplied, when it activates "breaker on?" etc.. The manual makes me scratch my head even more, as it's startup procedure for them says to turn all your batteries on one by one, THEN turn your inverter on.. That seems like it would defeat the pre-charge timer completely turning the batteries on first then closing a breaker on your inverter.

For my EG4LL batteries with my Schneider XW Pro 6848, I powered the battery BMS up with the small switch, then closed the breaker on the battery. The inverter instantly jumped to life and worked. Did it pre-charge it any or just give her full power? Who knows, but it worked that one time....

Signature Solar isn't doing themselves or us any favors by not publishing detailed information on how their pre-charge circuit works. It should be documented in the manuals.

 

[Quattrohead]

All we need from the inverter is to not turn on immediately. Either manual precharge or BMS doing it, we want capacitors to reach near full voltage and then switch closed for low resistance before inverter starts sucking multiple amps.

My theory is 2 different types of inverter, 1 that will run without a battery and 1 that must have a battery.
Let's take our much talked about SPF 5000 ES. It can run without a battery so it must generate the 48V from the AC power. It can control how quick this power supply can ramp up from zero to 48V. All is well when you connect a battery as the capacitors are already charged.
Now looking at the SPF 6000T, it needs a battery connected before it will do anything. Capacitors need to charge from the battery and suck a huge amount of power to do so.
In either case, it does not matter if the inverter is producing output right away or not. In fact neither do but that is not part of the problem.