diy solar

diy solar

EG4 18K - Air Conditioning won’t run without grid

A

AW1511

New Member
Joined
Aug 8, 2021
Messages
12
I have run almost 1MWh through the 18k+ 2x PowerPro (400A, 20kW peak) Batteries + 18kw panels and it’s been working great (mainly off grid). Now that we are hitting a couple hot days in Texas I have tried to use my 4ton lennox xp21-048-230-04. It will not run while I have the inverter disconnected from the grid. I have purchased a soft start and will go into details.

The units RLA=21A(5kW) and LRA=104A(25kW). After installing the soft start I read ~41A(10kW) peak startup while on grid power (By grid power I mean grid connected through 18k to the load) and everything runs fine. This is within the capability of the inverter so that’s expected.

After this testing I turned off my grid disconnect(running on batteries and solar) and the air conditioning will not startup and run. I thought this was odd so I re-connected the grid and the ac started up fine. I let it run for a few minutes and the data shows that ~5kW is being pulled from the batteries as expected with no grid power being used. Now I turn off my grid disconnect and the air conditioning shuts down. I can’t figure out why the 18k can’t keep the air conditioning running while it is in its 5kw steady state or why it is not capable of starting it with the soft start.

My 2-ton unit runs on the 18k perfectly fine with grid power turned off.

My dad is working through the troubleshooting process with signature solar, but wanted to see if anyone here could help.

Firmware version is fAAB-1717
 
Last edited:
Whilst this is not your problem, just note that my Easy Start will disconnect the compressor if the inverter switches modes, you then will have to wait for the protection timeout.
Can you list/dump your settings for the EG4 18k.
 
I'm watching this with interest because this has always been my question with all of these newer hi frequency inverters. Starting large inductive loads consistently, time and again, for several years.

Perhaps it has nothing to do with the load, but it will be interesting how this thread plays out.
 
AW1511 said:
I have run almost 1MWh through the 18k+ 2x PP Batteries + 18kw panels and it’s been working great (mainly off grid). Now that we are hitting a couple hot days in Texas I have tried to use my 4ton lennox xp21-048-230-04. It will not run while I have the inverter disconnected from the grid. I have purchased a soft start and will go into details.

The units RLA=21A(5kW) and LRA=104A(25kW). After installing the soft start I read ~41A(10kW) peak startup while on grid power (By grid power I mean grid connected through 18k to the load) and everything runs fine. This is within the capability of the inverter so that’s expected.

After this testing I turned off my grid disconnect(running on batteries and solar) and the air conditioning will not startup and run. I thought this was odd so I re-connected the grid and the ac started up fine. I let it run for a few minutes and the data shows that ~5kW is being pulled from the batteries as expected with no grid power being used. Now I turn off my grid disconnect and the air conditioning shuts down. I can’t figure out why the 18k can’t keep the air conditioning running while it is in its 5kw steady state or why it is not capable of starting it with the soft start.

My 2-ton unit runs on the 18k perfectly fine with grid power turned off.

My dad is working through the troubleshooting process with signature solar, but wanted to see if anyone here could help.

Firmware version is fAAB-1717
Click to expand...

If you could DM your inverters serial number, I can take a look at this.
 
Could the Soft Start be bad,(incompatible) because the grid would not need it to run?
 
Last edited:
AW1511 said:
I have run almost 1MWh through the 18k+ 2x PP Batteries + 18kw panels and it’s been working great (mainly off grid). Now that we are hitting a couple hot days in Texas I have tried to use my 4ton lennox xp21-048-230-04. It will not run while I have the inverter disconnected from the grid. I have purchased a soft start and will go into details.

The units RLA=21A(5kW) and LRA=104A(25kW). After installing the soft start I read ~41A(10kW) peak startup while on grid power (By grid power I mean grid connected through 18k to the load) and everything runs fine. This is within the capability of the inverter so that’s expected.

After this testing I turned off my grid disconnect(running on batteries and solar) and the air conditioning will not startup and run. I thought this was odd so I re-connected the grid and the ac started up fine. I let it run for a few minutes and the data shows that ~5kW is being pulled from the batteries as expected with no grid power being used. Now I turn off my grid disconnect and the air conditioning shuts down. I can’t figure out why the 18k can’t keep the air conditioning running while it is in its 5kw steady state or why it is not capable of starting it with the soft start.

My 2-ton unit runs on the 18k perfectly fine with grid power turned off.

My dad is working through the troubleshooting process with signature solar, but wanted to see if anyone here could help.

Firmware version is fAAB-1717
Click to expand...
What is a PP battery?

Ability to start loads depends on available power. How much are the panels producing and how much can be pulled from batteries? I think you need more battery power than just a pair of 48V batteries even if the panels are producing.

The 18Kpv is not an 18Kw inverter. It is 12Kw when on battery power and claimed to be 15Kw with PV. Your LRA surge even with soft start could be higher than 15Kw.
 
Zwy said:
What is a PP battery?

Ability to start loads depends on available power. How much are the panels producing and how much can be pulled from batteries? I think you need more battery power than just a pair of 48V batteries even if the panels are producing.

The 18Kpv is not an 18Kw inverter. It is 12Kw when on battery power and claimed to be 15Kw with PV. Your LRA surge even with soft start could be higher than 15Kw.
Click to expand...
The eg4 power pro battery. 2x of these have a peak discharge capability of 400A or ~20kW.

The panels at the time of testing were putting out >5kW

I thought it may be the startup current issue even with the soft start and that is why I tried starting with the grid and then turning off the disconnect. This indicates to me it’s not just a startup problem, but a running problem. Although the running shutdown may be due to a mode switching that happens when the grid is disconnected. Understand it’s a 12kW AC output, but should run this steady state just fine. And with a soft start and 15kW peak it should be able to start it with the soft start
 
Quattrohead said:
Whilst this is not your problem, just note that my Easy Start will disconnect the compressor if the inverter switches modes, you then will have to wait for the protection timeout.
Can you list/dump your settings for the EG4 18k.
Click to expand...
Can you explain this one in more detail? How long does it take to bring the compressor back?

Best way to dump setting here?
 
AW1511 said:
The eg4 power pro battery. 2x of these have a peak discharge capability of 400A or ~20kW.
Click to expand...
Power Pro- thank you.

You most likely need more battery as has been mentioned.

AW1511 said:
The panels at the time of testing were putting out >5kW

I thought it may be the startup current issue even with the soft start and that is why I tried starting with the grid and then turning off the disconnect. This indicates to me it’s not just a startup problem, but a running problem. Although the running shutdown may be due to a mode switching that happens when the grid is disconnected. Understand it’s a 12kW AC output, but should run this steady state just fine. And with a soft start and 15kW peak it should be able to start it with the soft start
Click to expand...
How are you measuring peak LRA?
 
Do you know what Power Factor is?

Maybe your unit is recognizing bad power factor as the compressor starts and it's refusing to run.

Wattage is based on a power factor of 1. As soon as you power a heavy motor like a compressor the power factor goes off and you start to draw inductive power. This is typically measured in VA (Volt Amps). If you see something measured in Volt Amps it's not reliant on a power factor of 1. I'm thinking you can draw 12k of resistive power at a PF of 1 but you likely can't draw 12k of inductive power at a PF of say 45 degrees.

You can google power factor yourself but as a general indication, pulling the power factor off by 45 degrees with a motor will reduce your power from 12k to about 8500. (Cos 45 = .707, 12000 * .707 = 8484.).

Drawing the PF off from 1 is also really hard on the MOSFETS that are used to make inverter power, the commutator diodes work really hard and it gets noisy in there. I've worked on dozens of blown inverters that were hooked up to air conditioners, the two just don't get along very well. The software in yours may be saying NO just to save the circuitry.

In the end, not having AC when the power goes out is definitely a first world problem so my advice would be to consider how much time and money you want to spend solving this 'problem'.

Then again my unsolicited advice is worth exactly what you paid for it!
 
AW1511 said:
Can you explain this one in more detail? How long does it take to bring the compressor back?

Best way to dump setting here?
Click to expand...
This timeout depends on which soft start you have and any possible delay the compressor itself may have, 2 to 5 mins is typical.
Seems like Jared is going to help you out with it, please let us know what happens.
 
You must log in or register to reply here.

Similar threads

W
EG4 24v LifePower4 batteries with 18K inverter
Replies
0
Views
126
Warden
W
B
Eg4 18K generator start options
Replies
7
Views
521
bryanmccoy57
B
B
EG4 18K Automatic Grid Charge of EG4 Batteries
Replies
4
Views
397
TomC4306
TomC4306
V
Limitation to AC coupling with EG4 18K, help required...
3 4 5
Replies
88
Views
3K
SolarCzar
SolarCzar
H
My 18K PV Experience (Part 1)
2 3
Replies
48
Views
3K
WorldwideDave
WorldwideDave
Back
Top