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EG4 8k Inverter problems

J

John98642

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Washington State
I am brand new to the forum.

I purchased the new EG4 8kexp-240 inverter, Lifepower4 batteries and solar panels a few months ago and I am in the process of getting the system up and running now.

The inverter runs part of my shop (lights, drill press, chop saw, battery charger) just fine, but the air compressor and car lift are not running correctly. I am off-grid with it so far, but everything ran on-grid just fine last week.

The air compressor is 240 Volts and 15 Amps. The car lift is 120 Volts and 15.5 Amps. I have tested both on-grid with a clamp meter and both stay within the abilities of the 33 amp inverter ratings even when starting on grid power. Both units shoot the volts and amps all over the place when run with inverter and battery power(grid disconnected). The volts drop very low and the amps jump very high.

Interestingly, the chop saw is also 15 amps and 120 volts. It works great. No issues even under load.

I have tried the instructions with no success.

I have been trying to work with signature solar to get this figured out. So far no luck.

Please help,
John
 
Your start up amps may be 5 times higher that what your seeing, you may need soft starts on those units, hf inverters don’t have the start up power the lf heavy transformer units do
 
Do you have a label on the compressor and car lift with LRA? How much battery do you have? Can you measure the battery voltage at the inverter when trying to start one of them?
 
rodrick said:
Your start up amps may be 5 times higher that what your seeing, you may need soft starts on those units, hf inverters don’t have the start up power the lf heavy transformer units do
Click to expand...
Thanks for the input. I have reconnected the grid and ran a test with a clamp meter. The lift started at 18 amps and ran fine with 15 amps. Running the off grid should work since the specs say 33 amps delivered. It has a short start up of almost 50 amps available for a few seconds. I do not understand since it is within specs on the inverter and the observed use on grid is reasonable numbers.
 
Shimmy said:
Do you have a label on the compressor and car lift with LRA? How much battery do you have? Can you measure the battery voltage at the inverter when trying to start one of them?
Click to expand...
455F5048-A472-4790-88C5-581E32BA3A0D.jpeg4ABC0D63-2530-48FA-9364-0606973E8C6A.jpeg
Here are the labels. I have 6 - eg4 Lifepower4 batteries and the voltage never dropped below 51 V during the test.

Any help is greatly appreciated.
 
John98642 said:
Thanks for the input. I have reconnected the grid and ran a test with a clamp meter. The lift started at 18 amps and ran fine with 15 amps. Running the off grid should work since the specs say 33 amps delivered. It has a short start up of almost 50 amps available for a few seconds. I do not understand since it is within specs on the inverter and the observed use on grid is reasonable numbers.
Click to expand...
The unit has the ability to do 50 amps for one second and my guess is your exceeding that on startup
not all of the clamp meters can catch that split second surge that the inverter is seeing you may have to use a soft start to run those items some of these inverters are not very tolerant of surges
 
rodrick said:
The unit has the ability to do 50 amps for one second and my guess is your exceeding that on startup
not all of the clamp meters can catch that split second surge that the inverter is seeing you may have to use a soft start to run those items some of these inverters are not very tolerant of surges
Click to expand...
Good to know. I will do some more checking.

Thank you!
 
John98642 said:
Here are the labels. I have 6 - eg4 Lifepower4 batteries and the voltage never dropped below 51 V during the test.

Any help is greatly appreciated.
Click to expand...
Inrush on that motor should be around 80-90A, so a soft start or capacitor is the only option. Battery should be fine for starting though.
 
Shimmy said:
Inrush on that motor should be around 80-90A, so a soft start or capacitor is the only option. Battery should be fine for starting though.
Click to expand...
The breaker in the breaker box that it has been running on for years is 20 amps. Data plate says 15 amps (see pic above) and the clamp meter said 18 and then 15. Wire is 12 gauge and about 80’ long. None of that is good for 80-90 amps??? Really confused now!
 
John98642 said:
The breaker in the breaker box that it has been running on for years is 20 amps. Data plate says 15 amps (see pic above) and the clamp meter said 18 and then 15. Wire is 12 gauge and about 80’ long. None of that is good for 80-90 amps??? Really confused now!
Click to expand...
The inrush current is the maximum, instantaneous current draw by a device when you first power it on. It’s not sustained current, which would then cause all sorts of issues on 12ga wire. It’s the startup current, and it only lasts for a split second. Like @rodrick said, a lot of meters (cheaper ones) can’t detect the inrush current because it’s so fast.
 
John98642 said:
The breaker in the breaker box that it has been running on for years is 20 amps. Data plate says 15 amps (see pic above) and the clamp meter said 18 and then 15. Wire is 12 gauge and about 80’ long. None of that is good for 80-90 amps??? Really confused now!
Click to expand...
Inrush just lasts a few cycles through a few seconds. A 15A breaker can typically handle 6-10x inrush current.

*but* if you have #12 running 80' that could be your problem rather than the inverter (or in concert with).
 
Shimmy said:
Inrush just lasts a few cycles through a few seconds. A 15A breaker can typically handle 6-10x inrush current.

*but* if you have #12 running 80' that could be your problem rather than the inverter (or in concert with).
Click to expand...
Hi Shimmy, good info.

I purchased a clamp meter with “inrush” measuring. The 15 amp auto lift is spiking 76 amps on startup. Wow, I had no idea. No wonder the inverter has trouble.

First: I can physically reverse the lift to make the motor closer to the breaker box and the wire run shorter and/or I can rewire it to 230 (see data plate above). Will either or both of these bring the amp spike down below the inverter’s 50 amp startup threshold?

Second: Does adding a second inverter double the amp capacity for starting motors?

Thank you for enlightening me on the finer points with inverters and motors.


Thanks for helping,
John
 
So that pulls just over 9kw inrush @120v. I can’t imagine many, if any, split phase inverters that can pull that across one leg. I would wire in 240v to evenly distribute the load first across both legs and and try again. If that doesn’t work then look at another inverter.
 
John98642 said:
Hi Shimmy, good info.

I purchased a clamp meter with “inrush” measuring. The 15 amp auto lift is spiking 76 amps on startup. Wow, I had no idea. No wonder the inverter has trouble.

First: I can physically reverse the lift to make the motor closer to the breaker box and the wire run shorter and/or I can rewire it to 230 (see data plate above). Will either or both of these bring the amp spike down below the inverter’s 50 amp startup threshold?

Second: Does adding a second inverter double the amp capacity for starting motors?

Thank you for enlightening me on the finer points with inverters and motors.


Thanks for helping,
John
Click to expand...
Try 240V before moving the motor; it will reduce voltage drop and current, but the magnitude of inrush will be the same-- ~37A inrush vs ~7.5A running.
 
240v might work. Also adding an auto transformer would be probably work. Or soft starts. But adding another inverter might not help. Still high frequency.

Before I'd add another hi frequently inverter, I'd strongly consider getting a low frequency inverter like the Growatt 12kW or the Schneider XW pro.
 
I am running 2 lifts and a 120v air compressor off-grid with my 8k unit. My pumps have been wired for 240 and it is no issue. If your motor can be rewired to 240, you should have no problem.


I have since installed a 2nd unit and more batteries but 1 unit ran the shop just fine. Inverters are on back wall.
 
NCSolarGarage said:
I am running 2 lifts and a 120v air compressor off-grid with my 8k unit. My pumps have been wired for 240 and it is no issue. If your motor can be rewired to 240, you should have no problem.


I have since installed a 2nd unit and more batteries but 1 unit ran the shop just fine. Inverters are on back wall.
Click to expand...
Oh a dyno! how much power does that need to work ? ;-)
 
NCSolarGarage said:
I am running 2 lifts and a 120v air compressor off-grid with my 8k unit. My pumps have been wired for 240 and it is no issue. If your motor can be rewired to 240, you should have no problem.


I have since installed a 2nd unit and more batteries but 1 unit ran the shop just fine. Inverters are on back wall.
Click to expand...
So no issues like Will had with his 8ks?
 
fromport said:
Oh a dyno! how much power does that need to work ? ;-)
Click to expand...
Its on a 30A GFCI breaker. If only I could figure out how to rewire to it to charge the batteries :ROFLMAO:

ChrisG said:
So no issues like Will had with his 8ks?
Click to expand...
None. I also charge my Tesla at 30A for hrs on end with no issues. I admit there were plenty of firmware issues and I had to do a LOT of digging to get the modbus protocol working with my HA, but its mostly all good now. I'm on old firmware that limits power on mppt 3&4 when there is low sunlight, but I'm willing to deal with this tradeoff.
 
Update on my EG4 8k inverter in my shop. Still not powering my 1 hp car lift correctly.

Per the data plate on the motor, I rewired to 240 volts and cut the wire distance from the breaker box to the lift in half. It is plugged into the inverter circuit that I used last night to charge my EV at 32 amps for over 2 hours. I have been using it on grid power for years and it is a different sound on the inverter! I would describe it as a “warble”. It runs, but not right. See attached video.

Inrush current cut down from 76 amps on 110 volts to 47 amps on 220 volts (inverter good for 50 for 1 second). Running current is 8 amps now.

I am ready to move on with wiring more circuits, but this needs solved first.

Please help!

John
 

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