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EG4-Lifepower4 Short Circuit Protection

sten

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May 24, 2022
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I have a EG4 6.5k and 1 EG4 48v Lifepower4 battery. Everything was working fine until yesterday when i went to plug in my solar array (2 panels) it was still partially shaded so it was pulling prob 15w of power and 0.1a so barely anything. I pluged in the array to the inverter before i had my battery turned on, the inverter immediately started up and i immediately turned on my battery. The battery went into Alarm mode and upon diagnostic it showed

1 Charging MOS off
2 Discharge MOS off
3 Short Circuit Protection

I turned everything off and tried again without the panels but with inverter still connected, same issue alarm and errors.

I removed the inverter from the circuit and turned everything on and no alarm everything green with a SOC of 41%.

So i tried again reseting the battery and connecting the negative to see if that would work, again same issue alarm.

Another attempt with a 25w 30ohm 5% resister which didnt trigger the alarm but the resister got so hot i couldnt hold it... so i disconnected it again. Tried to hook up battery and same issue - alarm.

Everything works fine apart, but once together the battery short circuit protection kicks in.

ideas?

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Are you turning on the battery first and then turning on the Breaker?
Do you have an load attached to the Inverter when your powering it up?
Do you have another battery that you can use to precharge the inverter with?

This problem has been happening to several people but I just want to eliminate those possibilities.
 
Are you turning on the battery first and then turning on the Breaker?
Do you have an load attached to the Inverter when your powering it up?
Do you have another battery that you can use to precharge the inverter with?

This problem has been happening to several people but I just want to eliminate those possibilities.
I dont have the nader breaker in between - hooking it up now to test.

no load except inverter

I only have 1 battery.
 
Did you watch this video??? Search YouTube for

Proper Start Up Procedure Using EG4 LifePower4 Batteries and More!​

 
They are probably going to tell you that one battery is not sufficient!
It should be but that is what they will say.
 
Your battery has a circuit breaker which is mechanically connected to the BMS switch, which means, you turn-on the BMS when you close the battery circuit breaker and at the same time you electrically connect the battery to the inverter. The battery built-in current limiting resistor should be in the circuit when you colse the battery circuit breaker, in order to limit the in-rush current to the inverter and switches out a little later. So you want to make sure the inverter is off and then close the battery circuit breaker (have you tried this???).

You said " Another attempt with a 25w 30ohm 5% resister which didnt trigger the alarm but the resister got so hot i couldnt hold it... so i disconnected it again. Tried to hook up battery and same issue - alarm." Did you have the inverter on when you did this??? Something is wrong here because the in-rush current will last for a very short time and no continouse current unless you had the inverter on. Power=voltage * currrent = (V*V)/R= (i*i)*R. You see, you shouldn't have much current, if you plug in your numbers into those power formulas (25w 30ohm 48Volt).

You said " i went to plug in my solar array (2 panels) it was still partially shaded so it was pulling prob 15w of power". You are not meeting the minimum input PV voltage requirement by having only two solar panels in series. Did you measure the PV voltage to make sure that you have at leaset 90Vdc (look at the inverter PV array specification)???
 
Your battery has a circuit breaker which is mechanically connected to the BMS switch, which means, you turn-on the BMS when you close the battery circuit breaker and at the same time you electrically connect the battery to the inverter. The battery built-in current limiting resistor should be in the circuit when you colse the battery circuit breaker, in order to limit the in-rush current to the inverter and switches out a little later. So you want to make sure the inverter is off and then close the battery circuit breaker (have you tried this???).
Yes this is what i tired - worked with Richard from EG4 as well to test this.

You said " Another attempt with a 25w 30ohm 5% resister which didnt trigger the alarm but the resister got so hot i couldnt hold it... so i disconnected it again. Tried to hook up battery and same issue - alarm." Did you have the inverter on when you did this??? Something is wrong here because the in-rush current will last for a very short time and no continouse current unless you had the inverter on. Power=voltage * currrent = (V*V)/R= (i*i)*R. You see, you shouldn't have much current, if you plug in your numbers into those power formulas (25w 30ohm 48Volt).
I didnt have the inverter on. Always off, waiting for the battery to turn on the device.

Ill check it out the math...

You said " i went to plug in my solar array (2 panels) it was still partially shaded so it was pulling prob 15w of power". You are not meeting the minimum input PV voltage requirement by having only two solar panels in series. Did you measure the PV voltage to make sure that you have at leaset 90Vdc (look at the inverter PV array specification)???

I have 87V coming into the array which is enough to turn on the inverter (80V according to signature solar) but yeah not enough to ideally run the device.
 
It def was not on... Tried it a few times.

It could definitely be a fault at the inverter in that case. Not sure how it happened, but maybe some inrush blew a FET on the input, shorting it. That explains why the resistor gets hot: the capacitors don't hold the charge since they're shorted out.
 
@upnorthandpersonal is right - the inrush should literally be a few seconds at most - if it's trying for a long time and getting hot that is worrisome. I remember reading in a previous post you had the system up and running and then it stopped working after you connected solar - when you connected solar was it a hot connection or did you have the breaker closed etc? It very well could be that if you had solar plugged directly into your inverter that a FET was damaged and is now causing a short and the other ongoing issues. Typically you pre-charge prior to any DC input and if you didn't that might explain these issues. Let me know how the last test we tried went when you finish. Thanks!
 
I connected solar, but a very low wattage (shaded panels) but enough to turn on the inverter, when i realized inverter turned on i quickly turned on battery. Battery went into alarm, so i turned off entire system. Been stuck in that state ever since.
 
@upnorthandpersonal is right - the inrush should literally be a few seconds at most - if it's trying for a long time and getting hot that is worrisome. I remember reading in a previous post you had the system up and running and then it stopped working after you connected solar - when you connected solar was it a hot connection or did you have the breaker closed etc? It very well could be that if you had solar plugged directly into your inverter that a FET was damaged and is now causing a short and the other ongoing issues. Typically you pre-charge prior to any DC input and if you didn't that might explain these issues. Let me know how the last test we tried went when you finish. Thanks!
I don't know what "sten" has done to his inverter but there are multiple YouTube videos showing one can power loads just from the solar panels (of course, assuming the Sun stays around) without using a single battery. I have the same inverter and I like to know what would happen by just connecting my PV array to the inverter (and not closing the battery circuit breaker). I am assuming there will be no in-rush current issue at the inverter's PV input because the maximum current coming from the solar panels is limited to ~ 10 amps (one series string).
 
I don't know what "sten" has done to his inverter but there are multiple YouTube videos showing one can power loads just from the solar panels (of course, assuming the Sun stays around) without using a single battery. I have the same inverter and I like to know what would happen by just connecting my PV array to the inverter (and not closing the battery circuit breaker). I am assuming there will be no in-rush current issue at the inverter's PV input because the maximum current coming from the solar panels is limited to ~ 10 amps (one series string).
Sten agrees, connecting two 450w panels pulling basically no power shouldn't brick an inverter.
 
Sten agrees, connecting two 450w panels pulling basically no power shouldn't brick an inverter.
Yes, I am just trying to ensure there isn't something missing and cover all our bases. Were you ever able to complete the breaker install etc and test that yesterday?
 
@RichardfromEG4 no worries - dont take my comment the wrong way. I dont have a crimper for open ended lugs that came with the 4awg cable from the battery enclosure, needed to order. Good ol' amazon should have them here today. Will let u know asap! Thanks again!
 
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