Weird grid use spike and hum/rattle noise - EG4 6000xp

[Steelart99]

@EG4TechSolutionsTeam

I had a couple of spikes of grid imports with a weird hum/rattle noise associated with them. Is there a reason for this?

I have only two types of loads that are short duration with fairly high power usage: Deep well pump starting and furnace blower cycling. Well pump power usage (blue down arrows) is higher than the blower. In the image below (from yesterday) of my system performance, there are two times where the well pump start seems to drive brief grid imports (red up arrows). This is NOT typical but it has happened rarely in the past. Strangely, when this occurs I will hear a fairly loud humming/rattling coming from the inverter (or battery?) for about 20-30 seconds. There is not enough time for me to note it happening and get downstairs to my garage to video what the inverter and/or battery might be doing as it is occurring. I have also heard this humming/rattle noise when my system has automatically used grid input to charge my battery when it hits 20% SOC (insufficient PV), with the noise occurring upon grid input cycling OFF. Note: I have a single EG4 Wallmount battery.

I'm guessing that the brief grid power demand might be due to high starting current demand of the well pump which doesn't actually show in the data.

Is the noise a normal inverter symptom of grid power shutting off? What else could be causing this noise?

 

[macdaman]

Could it be related to....

M

Post in thread '6000xp causing transformer hum during AC to Inverting transition'

Dec 23, 2024

Is the hum occurring only during the transition to inverting mode? That's the only time mine dose it. Apparently, that normal for the 6000xp.

Yes. No noise during normal operation. No noise while on Grid. However, when changing over from Grid to Inverter, you hear the noise for 10-15 seconds.

• macdaman

M

Post in thread '6000xp causing transformer hum during AC to Inverting transition'

Dec 22, 2024

I got it from Current Connected. They're being very helpful in getting this resolved.

What was the resolution here? I too get a hum on a couple of transformer based battery backup devices.

• macdaman

S

Thread 'DC offset voltage sent to AC loads. How bad is it?'

Dec 10, 2024

When my inverter transitions from AC bypass to Inverting mode, it's putting out a DC offset of more than 3 volts.

It only lasts about 30 seconds and the voltage declines through that period, but it's enough to cause my UPS's and stereo receiver to hum, which is how I noticed it.

I have concern for my appliances and other equipment that are subject to this DC voltage each day during the transition.

I'm told by my vendor and the manufacturer that this is the way the inverter works. There's nothing wrong with it. The DC output is normal.

The control boards in furnaces, refrigeration...

• sollap
• Replies: 6
• Forum: DIY Solar General Discussion

 

[Steelart99]

@macdaman
@EG4TechSolutionsTeam
@SignatureSolarSupport
@SignatureSolarJess

Those threads seem to show the same symptoms as what I'm hearing. Thanks for tracking them down. I thought that the noise was coming from the 6000xp inverter or EG4 battery, but it's possible that the source is some other electronics or transformers downstairs. The furnace is in the same area ... so a possibility. I could never get downstairs fast enough to make an exact ID of the source.

I'll admit to not truly understanding all the possible electrical "drivers" annotated in the links you provided. Not my forte.

It appears that I should be able to shut off my PV input and trigger the inverter Grid charge function (1-hour) and then monitor what happens when the inverter switches back from grid input to inverter. At least I'd be in the area to identify the exact source of hum. Make sense?

As far as the grid input even being triggered (full battery), the only thought I had was that it was driven by the deep well pump starting current. But the system should be able to handle that transient per spec's and it only happens occasionally.

I purchased the inverter and battery from Signature Solar.

​

 

[SignatureSolarJess]

Hi! I'm sorry you're having trouble! I think getting you connected with the tech team would be best. I'm going to send you a DM for your name and order number, and we'll get you sorted out

 

[macdaman]

Those threads seem to show the same symptoms as what I'm hearing. Thanks for tracking them down. I thought that the noise was coming from the 6000xp inverter or EG4 battery, but it's possible that the source is some other electronics or transformers downstairs. The furnace is in the same area ... so a possibility. I could never get downstairs fast enough to make an exact ID of the source.

It appears that I should be able to shut off my PV input and trigger the inverter Grid charge function (1-hour) and then monitor what happens when the inverter switches back from grid input to inverter. At least I'd be in the area to identify the exact source of hum. Make sense?

As far as the grid input even being triggered (full battery), the only thought I had was that it was driven by the deep well pump starting current. But the system should be able to handle that transient per spec's and it only happens occasionally.

I purchased the inverter and battery from Signature Solar.

​

I ended up having to discontinue using two particular devices due to the hum. Some say no harm no foul, just a noise. Others wonder if long term damage may occur since this is behavior is not seen in the "real world". For now, I don't run any expensive items on the inverter.

 

[TM48]

But the system should be able to handle that transient per spec's and it only happens occasionally.

Have you measured it? What size motor?

 

[Kornbread]

Running one battery ... current limit of battery? Not looking at specs but guessing it has a max charge/discharge of 100amps. 100a(53v)=5300watts, or if the battery is low, 100a(50v)=5000w. The blue line is the well pump which looks to be pulling right around 5000w. That's probably why the aio sometimes pulls from grid when the well pump kicks on and runs. It might be a good idea, if finances afford, to invest in more storage capacity.

Odd noise, that's something concerning. Don't like any odd noises coming from electrical stuff as it makes me think something isn't right, and/or it's under a lot of load.

 

[Steelart99]

Have you measured it? What size motor?

1.5HP 240V, 11.6 full load amps. I have not measured the starting surge current but below are the battery and inverter specs

EG4 Wallmount Battery

EG4 6000xp Inverter

 

[Steelart99]

Running one battery ... current limit of battery? Not looking at specs but guessing it has a max charge/discharge of 100amps. 100a(53v)=5300watts, or if the battery is low, 100a(50v)=5000w. The blue line is the well pump which looks to be pulling right around 5000w. That's probably why the aio sometimes pulls from grid when the well pump kicks on and runs. It might be a good idea, if finances afford, to invest in more storage capacity.

Odd noise, that's something concerning. Don't like any odd noises coming from electrical stuff as it makes me think something isn't right, and/or it's under a lot of load.

EG4 Wallmount battery: 200A continuous charge/discharge rate. I only see this issue happening when the battery is at or near fully charged, which is when inverter switches from AC grid input back to inverter (PV input), i.e., 100% SOC.

FWIW, the yellow line (consumption) is made up of two primary loads. A lower level short frequency load which is my furnace blower kicking on/off and a somewhat random higher level spike which is my well pump. It comes on periodically to recharge my water pressure tank.

The blue line is solar PV.

I've been watching pricing on the same EG4 battery to purchase and install another in parallel to the existing battery.

Yesterday, after my battery was at 100% SOC, I went through multiple cycles of shutting the PV input off, waiting for the battery to drop to about 97% SOC and then manually starting the grid input. I monitored the inverter locally as the battery charge (from grid) rose up to 100% and then cycled off automatically. This is when I typically heard the hum ... upon changing from grid back to inverter. I did this 7 times and the hum only happened one time ... unfortunately, it was the one time I left the inverter location after my wife started yelling about an ant infestation ... sigh. I even ran the water until the well pump had kicked on for some of the cycles. Since I failed to catch and video the one time it happened, I'll have to try this experiment again.

 

[Kornbread]

EG4 Wallmount battery: 200A continuous charge/discharge rate. I only see this issue happening when the battery is at or near fully charged, which is when inverter switches from AC grid input back to inverter (PV input), i.e., 100% SOC.

FWIW, the yellow line (consumption) is made up of two primary loads. A lower level short frequency load which is my furnace blower kicking on/off and a somewhat random higher level spike which is my well pump. It comes on periodically to recharge my water pressure tank.

The blue line is solar PV.

I've been watching pricing on the same EG4 battery to purchase and install another in parallel to the existing battery.

Yesterday, after my battery was at 100% SOC, I went through multiple cycles of shutting the PV input off, waiting for the battery to drop to about 97% SOC and then manually starting the grid input. I monitored the inverter locally as the battery charge (from grid) rose up to 100% and then cycled off automatically. This is when I typically heard the hum ... upon changing from grid back to inverter. I did this 7 times and the hum only happened one time ... unfortunately, it was the one time I left the inverter location after my wife started yelling about an ant infestation ... sigh. I even ran the water until the well pump had kicked on for some of the cycles. Since I failed to catch and video the one time it happened, I'll have to try this experiment again.

Just an fyi if it comes time to replace the pump, some of the grundfos deep well pumps have a soft start built in which helps eliminate startup inrush. Being on a well for the past 30+years, we've replaced several pumps. Unfortunately, when it came time to replace the pumps, it was always an unplanned emergency and we used whatever brand the local well contractor had on hand.

Something about adding that second battery that makes life on an inverter easier, even if the specs don't call it out.

Hope that hum is just a loose part vibrating @60Hz and not something like a relay going freakazoid. Home security system pointed that direction?

 

[Kornbread]

After some reading ... what @macdaman posted. More specifically, post #23 by RCinFLA in macdaman's above post #2. It sounds like the aio's internal inverter takes a while to sinc with the grid and the hum depends on just how far out of sinc the two are at contact. The further out of sinc, the more they fight. Also sounds like this is normal for the eg4 6000xp.

Reposting RCinFLA below:

 

[Lprantner]

1.5HP 230V, 11.6 full load amps. I have not measured the starting surge current but below are the battery and inverter specs

EG4 Wallmount Battery
View attachment 298323
EG4 6000xp Inverter
View attachment 298329

Actually, the 6000xp's max continuous output current is 12.5A per leg, NOT 25A. So, 240V (both legs of 120v) x 25A is 6000W. I could be wrong. It seems to be the same a my Sungold 6kw inverter. Go over 3kw on either leg and the inverter will fault.

 

[shopman]

Actually, the 6000xp's max continuous output current is 12.5A per leg, NOT 25A. So, 240V (both legs of 120v) x 25A is 6000W. I could be wrong. It seems to be the same a my Sungold 6kw inverter. Go over 3kw on either leg and the inverter will fault.

P=E x I so 3000/120=25 amps per leg.

 

[TM48]

1.5HP 240V, 11.6 full load amps. I have not measured the starting surge current but below are the battery and inverter specs

EG4 Wallmount Battery
View attachment 298323
EG4 6000xp Inverter
View attachment 298329

My old 1 hp well pump had a 43 amp startup amperage. It ran at about 8.5. I replaced it with a Grundfos 1 hp which runs at 7-8 amps and startup is 11.3. You are definitely overloading your inverter causing it to switch to grid which is not conducive to it's longevity. I have a pair of 6000's for this reason. Your pump probably pulls more that 60 amps on startup which exceeds the surge capability of a single 6000.

 

[SplitUniverse]

Yesterday, after my battery was at 100% SOC, I went through multiple cycles of shutting the PV input off, waiting for the battery to drop to about 97% SOC and then manually starting the grid input. I monitored the inverter locally as the battery charge (from grid) rose up to 100% and then cycled off automatically. This is when I typically heard the hum ... upon changing from grid back to inverter. I did this 7 times and the hum only happened one time ... unfortunately, it was the one time I left the inverter location after my wife started yelling about an ant infestation ... sigh. I even ran the water until the well pump had kicked on for some of the cycles. Since I failed to catch and video the one time it happened, I'll have to try this experiment again.

I would suggest you test this by reenacting the original scenario and not trying to emulate it.
Leave the system itself alone and just turn on a faucet until the pump kicks in. Turn off the faucet once the pump is on. if you need to recreate make sure to give the pump a few minutes of "rest" between the time it turn off and next reenactment.
There's a possibility that this is not related to the import from the grid but to the current distortions that the pump induces in the system at startup.

 

[Steelart99]

Just an fyi if it comes time to replace the pump, some of the grundfos deep well pumps have a soft start built in which helps eliminate startup inrush. Being on a well for the past 30+years, we've replaced several pumps. Unfortunately, when it came time to replace the pumps, it was always an unplanned emergency and we used whatever brand the local well contractor had on hand.

Something about adding that second battery that makes life on an inverter easier, even if the specs don't call it out.

Hope that hum is just a loose part vibrating @60Hz and not something like a relay going freakazoid. Home security system pointed that direction?

My well pump is 23+ years old and probably cycles 4-8 times daily for most of the year. More frequently when I have to water gardens (I'm in the high plains desert area of Colorado).

I've actually looked into the soft start pumps, but all pumps end up being expensive when your pump depth is 800-ft. I suppose I should look a bit more seriously. As you implied, it's probably better to get a good well pump before having to settle for what is available when there is a failure. And yeah ... I'm sure I'm getting near the end-of-life for current one.

 

[Steelart99]

I would suggest you test this by reenacting the original scenario and not trying to emulate it.
Leave the system itself alone and just turn on a faucet until the pump kicks in. Turn off the faucet once the pump is on. if you need to recreate make sure to give the pump a few minutes of "rest" between the time it turn off and next reenactment.
There's a possibility that this is not related to the import from the grid but to the current distortions that the pump induces in the system at startup.

I kinda have two issues ongoing:

1.) The grid input demand (short duration) when I don't think there should be upon well pump cycling, which is the scenario you noted. What you suggest is the scenario I tried to re-enact several times a couple of days back. That said, I was not rigorous in doing the cycle as "cleanly" as I should have. I'll redo this test cycle and put a surge-capable meter on the well pump to see what the actual load is. Of note, the well pump is on a 30-Amp circuit breaker.

2.) I also have the hum associated with the inverter switching from grid input to PV input/battery. That issue is not always associated with the well pump cycling. It has occurred several times just by the inverter making the switch from the grid-input when used to charge the battery on low PV days when it reaches 20% SOC. That switch from grid-input to PV/battery happens after the battery reaches 100% SOC.

Both issues have random occurrences.

 

[Steelart99]

My old 1 hp well pump had a 43 amp startup amperage. It ran at about 8.5. I replaced it with a Grundfos 1 hp which runs at 7-8 amps and startup is 11.3. You are definitely overloading your inverter causing it to switch to grid which is not conducive to it's longevity. I have a pair of 6000's for this reason. Your pump probably pulls more that 60 amps on startup which exceeds the surge capability of a single 6000.

Whoops, I missed your note above.

I agree that this part of my issue is likely due to the starting surge of the 1.5HP well pump. I had originally sized my inverter based on being able to handle the pump startup surge as the 6000xp has the ability to handle 12,000 watts for 3.5 seconds and 11,000 watts for 5 seconds.

Crudely, that means that the 6000xp should be able to handle ~45Amps (240V) for 5 seconds or ~50Amps for 3.5 seconds. Since the pump is 11.6 full load Amps (by spec), then the starting surge would seem to be 3.8x to 4.3x the operating current. Sounds like my pump is aging out ... sigh .... I'd always heard that starting surge is usually 3-4x the operating amperage.

 

[Steelart99]

After some reading ... what @macdaman posted. More specifically, post #23 by RCinFLA in macdaman's above post #2. It sounds like the aio's internal inverter takes a while to sinc with the grid and the hum depends on just how far out of sinc the two are at contact. The further out of sinc, the more they fight. Also sounds like this is normal for the eg4 6000xp.

I had read this also ... but I was hoping that there might be an "alternate" rationale for my issues. I've been trying to identify what piece of hardware is actually making the hum. I hear it from upstairs but can't make it down to the garage/basement area fast enough to figure out what is going on, i.e., is the actual inverter or battery making the hum, or might it be the furnace transformer due to the sync issue, or what???

The only other electronics in the area that I'm hearing the hum from are a stair-stepper and treadmill. Both have DC motors and thus transformers.

 

[TM48]

Whoops, I missed your note above.

I agree that this part of my issue is likely due to the starting surge of the 1.5HP well pump. I had originally sized my inverter based on being able to handle the pump startup surge as the 6000xp has the ability to handle 12,000 watts for 3.5 seconds and 11,000 watts for 5 seconds.

Crudely, that means that the 6000xp should be able to handle ~45Amps (240V) for 5 seconds or ~50Amps for 3.5 seconds. Since the pump is 11.6 full load Amps (by spec), then the starting surge would seem to be 3.8x to 4.3x the operating current. Sounds like my pump is aging out ... sigh .... I'd always heard that starting surge is usually 3-4x the operating amperage.

Depending on the brand you may be able to lookup the LRA of your pump. Given my old 1 hp Stayrite was listed at 43 I assume yours would be greater than 60 but unless you actually measure it it's guesswork.

 

[SplitUniverse]

Have someone turn on the faucet until the pump kicks in, hang out next to the Inverter in the meanwhile.
With the grid connected I would hope that the inverter is using the grid to keep synchronized even when not drawing from the grid, that would make the most sense, .....

 

[Steelart99]

Depending on the brand you may be able to lookup the LRA of your pump. Given my old 1 hp Stayrite was listed at 43 I assume yours would be greater than 60 but unless you actually measure it it's guesswork.

The LRA on my pump is 41 Amps. I'll be measuring the starting surge when I start testing again. Hopefully, I can find the right wire to put my clamp meter on . I think it is the yellow one based on the well pump info on my following post.

Yes, I have a meter made to grab the max starting surge current

 

[Steelart99]

This is my well pump

 

[TM48]

The LRA on my pump is 41 Amps. I'll be measuring the starting surge when I start testing again. Hopefully, I can find the right wire to put my clamp meter on . I think it is the yellow one based on the well pump info on my following post.

Yes, I have a meter made to grab the max starting surge current

Three wire pumps have a lower LRA then my 2 wire. Your close to the surge capability of a 6000. But that assumes nothing else is drawing power. One question I had is why do you charge to 100% with grid. How much PV do you have?

 

[Steelart99]

Three wire pumps have a lower LRA then my 2 wire. Your close to the surge capability of a 6000. But that assumes nothing else is drawing power. One question I had is why do you charge to 100% with grid. How much PV do you have?

I only charge via the grid during multiple day snow storms or cloudy days when my battery drops to 20% SOC. Then the inverter automatically kicks in the grid-input to charge the battery to 100% SOC (per my settings). The inverter then switches back to PV/battery. This has only happened about 6-8 times since I started my system up in early Dec-2024.

On clear spring/summer days PV usually takes about 2-3hours to recharge my battery while servicing all my loads. In the winter (short days), my overnight usage would typically push my battery SOC to about 30% before sufficient PV was available to handle my load plus recharge the battery.

I have twenty 400W bifacial solar panels (2 parallel 10-panel circuits). That is about the upper limit to work with the 6000xp. I have enough PV to keep a second battery charged ... most of the time. Second battery is on my to-buy list.