04 fault

[Jmaccracken]

I keep getting a 04 fault code on a midnight solar mn3024 diy inverter. The battery is fully charged, it’s a Big Battery 24v Falcon Elite. The inverter powers up ok, but shortly after I switch on a breaker the code comes up even if nothing is turned on and it doesn’t seem to matter which breaker I turn on. What could be causing this? TIA.

 

[OffGridForGood]

What does the Midnight Solar MN3024 manual identify for a fault 04 to occur?

 

[42OhmsPA]

What does the Midnight Solar MN3024 manual identify for a fault 04 to occur?

My SRNE manual shows battery low voltage, but that's for a different model.
We need to know battery voltages and inverter set points.
The mention of shortly after a breaker has me curious.

 

[OffGridForGood]

The mention of shortly after a breaker has me curious.

If the inverter 'thinks' the battery voltage is low, it would cut off AC output, but I wanted the OP to confirm just what fault 04 actually is, and I didn't feel energetic enough tonight to go searching for myself! LOL. Agree, on several of my inverters F04 is battery low. but not sure about MN 3024.

Okay looked up the manual for the 3024, Fault 04 is low battery voltage, stop discharge alarm.

So, time to put a digital multimeter on this battery and see what it actually is reading - at rest.
Then put some load on the battery and check voltage again. Often when a battery is near end of service this is the type of failure we first notice, the battery may appear to be "50% SOC" at rest, but as soon as we put a load on the battery the voltage drops like a rock.
If the OP doesn't have a DMM to check the battery, they could try charging it up to 100% and see if the fault clears.

 

[Jmaccracken]

What does the Midnight Solar MN3024 manual identify for a fault 04 to occur?

The manual says “LowBattEod Battery undervoltage stop discharge alarm” but the battery is fully charged. It does cut off AC output with the code.

 

[Jmaccracken]

My SRNE manual shows battery low voltage, but that's for a different model.
We need to know battery voltages and inverter set points.
The mention of shortly after a breaker has me curious.

Tha battery is fully charged at 27-28 v. The set points are where the seller said they should be.

 

[OffGridForGood]

Testing a battery at rest means nothing.
Put a load on that battery and test the voltage drop with a digital multimeter.

(this came up just a few weeks ago, our eldest daughter calls, 'car will not start but it's not the battery'
Really ? I said, how do you figure it is not the battery? - oh a guy in the parking lot put his meter on it and shows 12.6 volts so all good"
Sure, I said, now have that "Guy" measure with his meter while you turn the key to engage the starter motor- yupp 7 volts.

 

[42OhmsPA]

Tha battery is fully charged at 27-28 v. The set points are where the seller said they should be.

So the inverter is already powered from the battery and it errors out when you turn on / close an AC breaker?

 

[Jmaccracken]

Yes.

 

[42OhmsPA]

Hmmm. Have you measured voltage at the inverter output before turning on the AC output breaker?
Is this a new setup? Have you verified settings are correct and triple checked wiring?