EG4-Lifepower4 Short Circuit Protection

[dgjonesy]

So sten I had the exact same battery behavior happen to me last night.

I have a Lifepower4 and MPP LV6048 that has been running fine since early Apr. 2022. I noticed last night that I couldn’t contact my Raspberry Pi Running SolarAssistant to check on the system. Went down stairs and saw inverter off and battery alarm on. Tried to turn battery back on and it tries to run but goes into Alarm Mode. I am able to run battery and inverter with 100W 8 Ohm resistor in pos supply line.

I could not get to SS Support line thru phone today so sent them an email. Waiting to see what happens.

 

[sten]

@dgjonesy message @RichardfromEG4 he's awesome at helping out

 

[dgjonesy]

Ok after disconnecting my PV array from the MPP LV6048 I was able to turn on the Lifepower4 without it going into alarm mode and then turn on the LV6048. Everything is running fine after then reconnecting the PV array.

SS support was useless and they said exactly what Robby said they would here : one battery is not enough for this inverter

 

[z_zk_z]

Ok after disconnecting my PV array from the MPP LV6048 I was able to turn on the Lifepower4 without it going into alarm mode and then turn on the LV6048. Everything is running fine after then reconnecting the PV array.

SS support was useless and they said exactly what Robby said they would here : one battery is not enough for this inverter

Can I ask you a question? Are you completely off- grid or is the input of your inverter connected to the grid? I am trying to figure out where the circuit board of your inverter (its control logic) is getting its electricity for its operation. Thanks ?

 

[dgjonesy]

Can I ask you a question? Are you completely off- grid or is the input of your inverter connected to the grid? I am trying to figure out where the circuit board of your inverter (its control logic) is getting its electricity for its operation. Thanks ?

Z,

I am completely off grid. I’m pretty sure the circuit board gets power from the battery.

 

[ncsolarelectric]

Sten agrees, connecting two 450w panels pulling basically no power shouldn't brick an inverter.

When you connect the battery, it has a pre-charge resistor that you can use to pre-charge the inverter. Since you didn't have the battery turned on, do you know for certain that it had already been precharged before you connected the PV string? Eventually, the energy still needs to go to that capacitor bank, and if it's discharged, then the PV will charge it with its maximum current, and that can blow the FET just as easily as a spark from the battery.
When I designed inverters, the pre-charge resistor was always in the inverter and was not "user-dependent". The capacitors got precharged every time before the relay would bypass the resistor.

 

[Shimmy]

I'm starting to hate the idea of all-in-one units. It seems like you really need a bunch of external parts to make it work properly (introducing opportunities for screw-up). Also feels like the EG4 could really use something like Schneider's Mini-PDP to integrate the breakers into a less constrained package, but keeping it neat.

 

[chess-equality]

Sten agrees, connecting two 450w panels pulling basically no power shouldn't brick an inverter.

This third person reference made my day ?

 

[z_zk_z]

When you connect the battery, it has a pre-charge resistor that you can use to pre-charge the inverter. Since you didn't have the battery turned on, do you know for certain that it had already been precharged before you connected the PV string? Eventually, the energy still needs to go to that capacitor bank, and if it's discharged, then the PV will charge it with its maximum current, and that can blow the FET just as easily as a spark from the battery.
When I designed inverters, the pre-charge resistor was always in the inverter and was not "user-dependent". The capacitors got precharged every time before the relay would bypass the resistor.

There are a few YouTube videos showing one is able to energize electrical loads only from solar panels by feeding an inverter, without using a single battery (assuming it is a sunny day). Under this situation (and being off grid), the inverter circuit boards (including its FET drivers) are not energized until they somehow get electricity from the solar panels (people have posted the inverter uses ~80 watts itself). If the inverter is not designed correctly (with input relays), it is very dangerous to take up to 500 Volt DC coming from the solar panels and apply it to an inverter which is NOT somehow ALREADY energized (and with its FET drivers in a known off state). Same thing can be said when connecting batteries to the inverter. One needs to make 100% sure that the built-in circuit boards of the inverter are fully enerzied before applying source voltages or have any loads on the inverter. One easy check is to see if the inverter is drawing ~80 watts from the batteries or solar panels before closing any load circuit breaker.

 

[McRod]

Sten, did this get resolved? I am having a similar issue and want to know if/how it was fixed?

Thanks.

 

[ncsolarelectric]

There are a few YouTube videos showing one is able to energize electrical loads only from solar panels by feeding an inverter, without using a single battery (assuming it is a sunny day). Under this situation (and being off grid), the inverter circuit boards (including its FET drivers) are not energized until they somehow get electricity from the solar panels (people have posted the inverter uses ~80 watts itself). If the inverter is not designed correctly (with input relays), it is very dangerous to take up to 500 Volt DC coming from the solar panels and apply it to an inverter which is NOT somehow ALREADY energized (and with its FET drivers in a known off state). Same thing can be said when connecting batteries to the inverter. One needs to make 100% sure that the built-in circuit boards of the inverter are fully enerzied before applying source voltages or have any loads on the inverter. One easy check is to see if the inverter is drawing ~80 watts from the batteries or solar panels before closing any load circuit breaker.

Or the manufacturer could be relying on an external DC disconnect switch, and that wiring is not being done with "Live" PV wires directly from the panels in direct sunlight. In companies I've worked for, safety protocols require all wiring must be done "de-energized" before the panels are connected. That's the last step after all the wiring is checked and signed off. Not saying the results would be different but just be safe. Safety First!

 

[McRod]

So sten I had the exact same battery behavior happen to me last night.

...I am able to run battery and inverter with 100W 8 Ohm resistor in pos supply line...

How did you wire in this resistor? Is this your solution? Did SS get back to you?

I found an 8 ohm resistor on Amazon, is that where you purchased?

 

[z_zk_z]

How did you wire in this resistor? Is this your solution? Did SS get back to you?

I found an 8 ohm resistor on Amazon, is that where you purchased?

Sorry McRod for jumping in, this YouTube video has the parts... PS. you may not need those parts, if your battery has a built-in current limiting resistor and its own circuit breaker...

 

[McRod]

Sorry McRod for jumping in, this YouTube video has the parts... PS. you may not need those parts, if your battery has a built-in current limiting resistor and its own circuit breaker...

Ok, thanks for that. As I understand, the EG4 battery has both a breaker/switch and pre charge resistor. So I don't see how any of that would help.

Also, this simply seems to reduce the spark on connecting cables. Once the system is connected and operational, I don't see a need for this.

 

[z_zk_z]

Ok, thanks for that. As I understand, the EG4 battery has both a breaker/switch and pre charge resistor. So I don't see how any of that would help.

Also, this simply seems to reduce the spark on connecting cables. Once the system is connected and operational, I don't see a need for this.

True, you don't need any of the parts mentioned in the video with EG4 batteries. You just need to follow the power-up (start-up) procedures mentioned in SS and YouTube videos (every time you energize your system)... the extra pre-charge resistor/switch (mentioned in the video) only helps, if you don't trust how the battery starts up and charges the input capacitors of the inverter...

 

[dgjonesy]

How did you wire in this resistor? Is this your solution? Did SS get back to you?

I found an 8 ohm resistor on Amazon, is that where you purchased?

McRod,

I placed one end of the resistor on the EG4 + terminal and connected the other end of the resistor to the + battery wire. That allowed me to turn on the EG4 without a short circuit alarm being tripped, which then allowed the LV6048 to power up. Of course this
was not a real solution to the problem but a trouble shooting test. Funny thing is that the EG4 Lifepower4 is supposed to already have a pre charge resistor. I did purchase the resistor from Amazon.

SS was useless in helping to solve this issue, they just said I needed to get another battery because 1 battery is not enough for the LV 6048.

I did finally resolve the issue by disconnecting my PV array and all loads before trying to turn on the EG4. No precharge resistor needed.

Hopefully this helps someone who may have the same issue.

 

[McRod]

McRod,

I placed one end of the resistor on the EG4 + terminal and connected the other end of the resistor to the + battery wire. That allowed me to turn on the EG4 without a short circuit alarm being tripped, which then allowed the LV6048 to power up. Of course this
was not a real solution to the problem but a trouble shooting test. Funny thing is that the EG4 Lifepower4 is supposed to already have a pre charge resistor. I did purchase the resistor from Amazon.

SS was useless in helping to solve this issue, they just said I needed to get another battery because 1 battery is not enough for the LV 6048.

I did finally resolve the issue by disconnecting my PV array and all loads before trying to turn on the EG4. No precharge resistor needed.

Hopefully this helps someone who may have the same issue.

Ok, I think that's a different problem than what I have. I can turn on the batteries without them tripping if I have DC power. My problem is the batteries trip when I turn OFF the AC power input (i.e shore power or generator).

 

[sten]

Sten, did this get resolved? I am having a similar issue and want to know if/how it was fixed?

Thanks.

Not yet.... Waiting for a solution. Gonna try to add another battery and see.

 

[Lilikoi_Heavy_Industries]

Not yet.... Waiting for a solution. Gonna try to add another battery and see.

sten, please let me know if unwelcome or unhelpful and I'll just delete this, best wishes with resolution on the issue!!!

I don't think there's another real solution other than adding another battery, replacing the BMS, or moving to 3kw inverters instead... Personally I don't think they're going to tune the BMS shutdown timing to be more aggressive, because the packs still work if you buy enough of them and get the wiring just right. They made a video on youtube I believe more recently--stating your inverter size should be 80% or less of your battery capacity. 6500 is 130% of 5120w (1 Lifepower4 51.2V doesn't pass), but 63% of 10240 watts (2 Lifepower4 51.2V).

The overly aggressive BMS shutdown timing could be addressing a known limitation of their BMS hardware, but it just doesn't make sense because our favorite youtube electronics experts are always telling us "wow the build looks so good!" etc (need a drinking game for these phrases).

But I was shopping for these batteries the same time as you, or maybe a month or two after? And I just don't think this kind of information was available at the time from Signature Solar. They had published that the outback 3kw inverter needed two batteries by May? but I'm not sure ANY of this was published as early as you started using them, I'm very sorry this has become a pain point in your setup.

When I ordered I remembered thinking they were cheap enough that replacing the BMS could be an option if that was the failure point, I was definitely nervous about issues like this.

 

[Subdood]

sten, please let me know if unwelcome or unhelpful and I'll just delete this, best wishes with resolution on the issue!!!

I don't think there's another real solution other than adding another battery, replacing the BMS, or moving to 3kw inverters instead... Personally I don't think they're going to tune the BMS shutdown timing to be more aggressive, because the packs still work if you buy enough of them and get the wiring just right. They made a video on youtube I believe more recently--stating your inverter size should be 80% or less of your battery capacity. 6500 is 130% of 5120w (1 Lifepower4 51.2V doesn't pass), but 63% of 10240 watts (2 Lifepower4 51.2V).

The overly aggressive BMS shutdown timing could be addressing a known limitation of their BMS hardware, but it just doesn't make sense because our favorite youtube electronics experts are always telling us "wow the build looks so good!" etc (need a drinking game for these phrases).

But I was shopping for these batteries the same time as you, or maybe a month or two after? And I just don't think this kind of information was available at the time from Signature Solar. They had published that the outback 3kw inverter needed two batteries by May? but I'm not sure ANY of this was published as early as you started using them, I'm very sorry this has become a pain point in your setup.

When I ordered I remembered thinking they were cheap enough that replacing the BMS could be an option if that was the failure point, I was definitely nervous about issues like this.

So, is this statement of theirs about needing an inverter that's less than 80% of the battery bank have any electrical reasons behind it? Does any other inverter and/or battery manufacturer make such a statement? I mean, it doesn't make sense to me. Their 6.5kW inverter's not always going to start up with full load on it, maybe it won't have any load on it, and may never get close to full load, so then it would meet their <80% requirement. It seems like they're just making it up as they go along.

I actually was in Texas last week visiting some friends and was going to pick up one of these Lifepower4 48v batts from their facility on the way back home. But, they were out of stock despite one of their salespersons kind of intimating that they did have them available. I had ordered it on-line from them, but had to cancel the order, as I wasn't going to pay $300 shipping it here, when I could've picked it up for free (after sales tax). They're on back order and won't be in until the middle of July, and the inverter won't be available until early August.

I've really wanted to get a system installed for our place using their battery and inverter, but these issues I seen regarding this battery have got me a bit gun shy.