Rant: EG4 48v 100ah battery has faulty BMS. Signature solar customer service is TERRIBLE

[Koldsimer]

So I contacted Signature Solar customer service to see what's going on. They had me run through all sorts of tests and eventually decided that the battery might be faulty and that they wanted to test it, so we arrange to get it shipped back to them.

Signature Solar didn't suggest something was wrong with his battery.

I guess you missed this.

Why does signature even have a tech team if they cant research a very basic issue and inverter requirement when it's related to the complaint the customer is making? There is story after story on this forum of your "tactical tech team" coming up short. They regularly don't return calls and emails, many times they are uninformed and lack the knowledge required to do basic troubleshooting. This particular thread is a perfect example.

I swear, your shoulder must hurt from all the patting yourself on the back. Keep telling yourself you can do no wrong. Maybe james will come along and stroke your posts with a like!

 

[Solar Guy Richard]

I guess you missed this.

Nope, I just read the actual ticket and email exchange, not what was written on the forum. I know you don't have access to that but I do and I'm not making assumptions, I'm directly quoting portions of the actual interaction.

 

[Solar Guy Richard]

if they cant research a very basic issue

They did research the issue - they provided an answer that something on his circuit was causing the battery to enter short circuit protect mode - exceeding 250a. They stated (correctly) that they believed the battery was performing to specs and that there was something in the customers system exceeding this threshold causing the error. Is the onus on Signature Solar's technical team to find the specs for every inverter, every possible connected appliance, and report the findings?

 

[SparkyJJO]

Is the onus on Signature Solar's technical team to find the specs for every inverter, every possible connected appliance, and report the findings?

No, that would be impossible.

 

[Solar Guy Richard]

No, that would be impossible.

I'm glad someone understands how ridiculous that suggestion was.

 

[SparkyJJO]

I've been on the receiving end of that sort of thing before and it is irritating. I'm an IT guy, that means I should know every software and hardware config and be able to answer why something isn't working right off the top of my head right?

 

[Hedges]

Another compounding issue could be the 60 Hz AC ripple pass through to the DC input side during surge event due to DC side electrolytic capacitors not having enough capacity to completely carry peak current of each surge AC waveform cycle. So there may be additional 60 Hz AC current peaks on DC side on top of RMS current needed to make 13kWac output and your DC input could be seeing as high as 525A current peaks coinciding with AC waveform peaks.

All inverters do that, including low frequency. (It would be possible for a high frequency inverter to draw constant current without 60 Hz ripple if it boosted to higher voltage on capacitors and allowed them to ripple.)

The capacitor bank would have to be quite large to supply 1/120 second of 200A. Lithium battery is "stiff", doesn't let voltage drop enough for capacitor to do that. 1 Farad = 1 ampere x second per volt.

I measured 65Arms ripple current from battery feeding 10kW resistive load. That was with 4x 6kW inverters, so 40% of rating.

Battery ripple current

After reading of someone tripping battery breakers at well below rating, I realized that could be due to pulses of current drawn by the inverter. Ideally capacitors would smooth out current draw so high frequency switching pulses and 60 Hz draw all came from the caps, and current from batteries...

diysolarforum.com

well, don't agree here.
the battery does what i needs to do and what has been agreed to when purchased.
the OP failed to read up on the minimum requirements of their own inverter.

If OP powered a 6kW load from a 6kW inverter, he would need enough battery for that.
If 6kW inverter tripped BMS when power applied, problem could be inrush due to large capacitor bank.

OP put a small battery on a 6kW inverter, and tried to power a 900W load. The DC current needed to start a 900W motor was too much for the BMS.

My worn-out 100 Ah AGM bank would have done it.

Midnight demonstrated their "Rosie" starting four DeWalt compressors simultaneously. Those are brush-type motors.

Midnite Solar Rosie HF Inverter 27kW Surge Test

Disclaimer: I'm not employed by nor compensated by Midnite Solar. I happen to be located near their factories in Arlington, WA and take advantage of the open door policy. I stop in several times a week and try to break stuff! If you stop in and ask if you can attempt to break stuff, they most...

diysolarforum.com

Midnite Solar Rosie HF Inverter 27kW Surge Test

It's kind of Amazing to see and for the OP that knows what is happening I get his excitement. Unfortunately as a viewer it was not as satisfying. It would have been nice if something showing some actual Power or Amps was being displayed. If you get that opportunity again please show us the...

diysolarforum.com

It appears this "eg4" battery quits with a fraction of a second current surge. I don't think the surge exceeds ratings over an entire 1/120th of a second half cycle, which would be 12kW or 12x surge for a vacuum cleaner. It may be that BMS responds to brief millisecond pulses across a sense resistor. Only some of my current sensors would register that. Clamp ammeter doesn't, and current transformer "rolls off" at that frequency, gives attenuated reading.

Does the BMS have an adjustable "overcurrent delay"?

https://www.reddit.com/r/OverkillSolarBMS/comments/fue716

4s 150A Daily BMS overcurrent

I have build a DIY 12v 280Ah LifePo4 battery box and connected it with a 150A Daily Common port smart BMS. Everything is working great. I have a 2000w converter connected and ran a test with a water heater rated at 2000w. My Victron Smart shunt said it pulled 2300w on the 12v side. Properly...

diysolarforum.com

They did research the issue - they provided an answer that something on his circuit was causing the battery to enter short circuit protect mode - exceeding 250a. They stated (correctly) that they believed the battery was performing to specs and that there was something in the customers system exceeding this threshold causing the error. Is the onus on Signature Solar's technical team to find the specs for every inverter, every possible connected appliance, and report the findings?

Could it be your battery works to spec?

But another brand battery just works?

 

[edseld]

If working correctly and properly designed, @100% SOC the breaker of EG4 should trip first before BMS do a short circuit.

 

[Browse]

Signature Solar is not in the wrong here and they have every right to publicly defend their company and reputation for an issue that is clearly on the customer's end regarding the design of a DIY system. If I owned a business like this, I'd have to weigh the cost of return shipping and reselling a used product at a discount vs a lost and unhappy customer. You can't give stuff away and hope to remain profitable.

I don't believe this thread damages their reputation since they are clearly responsive to the complaint and the facts seem to support their position on the issue.

I wish I could buy the system Will just put together:

Maybe if I win the lottery soon, I will place an order.

 

[houseofancients]

I've been on the receiving end of that sort of thing before and it is irritating. I'm an IT guy, that means I should know every software and hardware config and be able to answer why something isn't working right off the top of my head right?

same here, been there, done that.
a PEBKAC is always brought as a drama, untill both sides come out

@Koldsimer can't help but stating that you seem to be out to set ss in a bad daylight every chance you get.
i assume this has to do with your issues from the past, where to my knowledge a final solution was never found, other that the conclusion it was more than likely a. a local to your setup problem, or b. a specific to your inverter problem.

please stop, as your not helping anyone, firstly yourself.
i believe i read you have a different battery from a different supplier, which is working.
happy for you, but there's no need to keep kicking down

 

[Solar Guy Richard]

Could it be your battery works to spec?

But another brand battery just works?

True - but if we say our battery will shut down at 250a, and it doesn't, and causes a fire or injury we would be having a completely (and likely more severe) thread to be responding to.

 

[Koldsimer]

same here, been there, done that.
a PEBKAC is always brought as a drama, untill both sides come out

@Koldsimer can't help but stating that you seem to be out to set ss in a bad daylight every chance you get.
i assume this has to do with your issues from the past, where to my knowledge a final solution was never found, other that the conclusion it was more than likely a. a local to your setup problem, or b. a specific to your inverter problem.

please stop, as your not helping anyone, firstly yourself.
i believe i read you have a different battery from a different supplier, which is working.
happy for you, but there's no need to keep kicking down

I gave up long ago on trying to help myself with signature. You can have your opinion and i can have mine about how they do business.

And by the way, i'm still getting conflicting information from them about how the bms pre-charge function works in their lifepower battery.

This is just like when they found out they were selling defective battery chargers advertised as 25a but only putting out 17a. They did a good job by offering multiple refund/return options but they still cant get it right because they refuse to refund the original shipping cost for those who had chargers shipped. So the customer is on the hook for something completely out of their control and through zero fault of their own. I know that pissed off several members here to the point they wont do business with signature ever again.

 

[houseofancients]

I gave up long ago on trying to help myself with signature. You can have your opinion and i can have mine about how they do business.

And by the way, i'm still getting conflicting information from them about how the bms pre-charge function works in their lifepower battery.

This is just like when they found out they were selling defective battery chargers advertised as 25a but only putting out 17a. They did a good job by offering multiple refund/return options but they still cant get it right because they refuse to refund the original shipping cost for those who had chargers shipped. So the customer is on the hook for something completely out of their control and through zero fault of their own. I know that pissed off several members here to the point they wont do business with signature ever again.

conclusion : you'll never be happy with ss, eventhough you got upgraded batteries and the issue seems isolated to your specific setup/inverter.

give it a break dude, your whining is getting old

 

[Solar Guy Richard]

They did a good job by offering multiple refund/return options but they still cant get it right because they refuse to refund the original shipping cost for those who had chargers shipped

If you return the unit you will get a 100% refund for the charger, return shipping refunded, and depending on your order any additional charges for the extra original shipping charge.
So, if you bought just the charger, you would get 100% refund of original shipping and charger, plus return shipping paid. If you bought the charger and 4 batteries, are you expecting we would refund more than the cost of the charger because it was on the same pallet that shipped with the batteries? As outlined in my other post regarding this issue:
1. Return the charger. We will pay shipping and refund the original charge of the charger back to you. (Note: This would include any shipping charges accrued FOR THE CHARGER as well)
2. Keep the charger. We will offer a STORE CREDIT for the difference in cost between a 25a charger and 18a charger, PLUS an additional $50.
3. Keep the charger. We will offer a REFUND for the difference in cost between a 25a charger and 18a charger. NO ADDITIONAL CREDIT.

And by the way, i'm still getting conflicting information from them about how the bms pre-charge function works in their lifepower battery.

Where are you getting conflicting information? I said I would research what Will had stated in his video - I never confirmed nor denied that. James has confirmed that pre-charge operates automatically.

 

[Hedges]

True - but if we say our battery will shut down at 250a, and it doesn't, and causes a fire or injury we would be having a completely (and likely more severe) thread to be responding to.

250A x 48V = 12kW
Did his 900W vacuum draw 12kW at startup?
Or did the inverter draw brief pulses of current exceeding 250A peak, yet no more than 100A or so mean?

I'm studying the issue of power supplies with spec that they draw up to 30A inrush from 208V. Even though they are 500W. Two supplies fed by 6A breaker.
Breaker trip curves can have 5x to 10x fast trip (curve C), or 10x to 20x (curve D). Because that is magnetic and moves a mass, higher than 10x would have to be sustained long enough to cause it to switch.

Electronics can be faster. Needs to be fast to protect itself, but might cause nuisance tripping. Semiconductors have current/time curves that go quite high for a short time, because it is all about deposited energy causing heating.

For instance, here's a 100A transistor that can carry 400A for 100 microseconds. That does limit how much a semiconductor switch BMS can let through. Relay based could tolerate more.

https://www.infineon.com/dgdl/irf1104pbf.pdf?fileId=5546d462533600a4015355da8d221895

Could be OP's problem is intersection of a BMS that protects itself against instantaneous current above spec, and an inverter that poorly filters its high frequency switching of current. Some filtering is needed to meet (higher frequency) FCC specs, but more is required to smooth DC current draw.

 

[AntronX]

Could be OP's problem is intersection of a BMS that protects itself against instantaneous current above spec, and an inverter that poorly filters its high frequency switching of current.

MOSFETs have turn-off delay. Short circuit fault has very fast current risetime so to protect the MOSFETs your short circuit detector has to be a bit proactive and react to the speed of current rise before it reaches short circuit trip level. So even after the controller issues turn-off signal and the gates on the MOSFETs are pulled down they will still allow for short circuit current buildup until t(off) has passed. With stiff current source behind them such as 1mOhm LFP battery and low impedance short in front, those silicon MOSFET dies are really what you can call "between a rock and a hard place".

 

[Koldsimer]

If you return the unit you will get a 100% refund for the charger, return shipping refunded, and depending on your order any additional charges for the extra original shipping charge.
So, if you bought just the charger, you would get 100% refund of original shipping and charger, plus return shipping paid. If you bought the charger and 4 batteries, are you expecting we would refund more than the cost of the charger because it was on the same pallet that shipped with the batteries? As outlined in my other post regarding this issue:
1. Return the charger. We will pay shipping and refund the original charge of the charger back to you. (Note: This would include any shipping charges accrued FOR THE CHARGER as well)
2. Keep the charger. We will offer a STORE CREDIT for the difference in cost between a 25a charger and 18a charger, PLUS an additional $50.
3. Keep the charger. We will offer a REFUND for the difference in cost between a 25a charger and 18a charger. NO ADDITIONAL CREDIT.

Where are you getting conflicting information? I said I would research what Will had stated in his video - I never confirmed nor denied that. James has confirmed that pre-charge operates automatically.

Not what Signature Solar was saying in the thread you started concerning your faulty chargers.

 

[Solar Guy Richard]

250A x 48V = 12kW
Did his 900W vacuum draw 12kW at startup?
Or did the inverter draw brief pulses of current exceeding 250A peak, yet no more than 100A or so mean?

I'm studying the issue of power supplies with spec that they draw up to 30A inrush from 208V. Even though they are 500W. Two supplies fed by 6A breaker.
Breaker trip curves can have 5x to 10x fast trip (curve C), or 10x to 20x (curve D). Because that is magnetic and moves a mass, higher than 10x would have to be sustained long enough to cause it to switch.

Electronics can be faster. Needs to be fast to protect itself, but might cause nuisance tripping. Semiconductors have current/time curves that go quite high for a short time, because it is all about deposited energy causing heating.

For instance, here's a 100A transistor that can carry 400A for 100 microseconds. That does limit how much a semiconductor switch BMS can let through. Relay based could tolerate more.

https://www.infineon.com/dgdl/irf1104pbf.pdf?fileId=5546d462533600a4015355da8d221895

Could be OP's problem is intersection of a BMS that protects itself against instantaneous current above spec, and an inverter that poorly filters its high frequency switching of current. Some filtering is needed to meet (higher frequency) FCC specs, but more is required to smooth DC current draw.

I don't think anyone here is saying his vacuum is drawing 12kW. The battery doesn't care for the load amount, overcurrent is measured in amps only - and if it exceeds 250a it will turn off in .1ms.

 

[AntronX]

and if it exceeds 250a it will turn off in .1ms.

EG4 manual says 1 sec delay at > 250A. You may want to update it.
Consider adding short circuit trip level vs. current risetime chart to better spec how short circuit protection behaves so you can avoid future misunderstandings like this thread.

 

[Solar Guy Richard]

Not what Signature Solar was saying in the thread you started concerning your faulty chargers.

This is such a disingenuous post. You are quoting someone who posted on the first page of a 5 page post, in which I later VERY CLEARLY advise that we are taking care of this. You are literally going out of your way to paint us in a bad light by quoting an issue that was addressed and fixed and the misunderstanding from our team was cleared up. He received the full refund, with no issues. Here's a screenshot a page later:

Seriously, if you are going to try to make me look bad don't make it so easy for me to find a post on the same thread where I fixed the issue.