EG4-LL (V2) pre-charge resistor - how to do correct pre-charging?

[fmeili1]

Hi,

I wonder if the EG4-LL (V2) still has the pre-charge resistor and if it does, is the procedure the same to activate it like in the EG4 LifePower4? I found Signature Solar videos about the correct pre-charge cycling of the EG4 LifePower4 battery, but NOT for the EG4-LL (V2). Also, in the manual of the EG4-LL (V2) there is no pre-charge resistor and sequence mentioned but it is in the EG4 LifePower4 manual!

If I try to use the same procedure for the EG4-LL (V2) which is described for the EG4 LifePower4, I don't have the LED lights cycle and also don't hear a click noise like the EG4 LifePower4 does?

Until now, I've only done some "dry" tests to activate the pre-charge cycle on the battery - without the inverters connected. Maybe the pre-charge cycle only starts, if an inverter is connected (I guess this is not the case, but I don't really know)?

For EG4 LifePower4 I found the following procedure to activate the pre-charge cycle:

1. Turn off the batteries (the BMS buttons and the breakers on the front of the batteries) - this step I've not done yet.
2. Connect the inverters to the batteries (switch on the breakers between the batteries and the inverters)
3. Switch on the BMS of the batteries
4. Switch on the breakers on the batteries - this step should start the pre-charge cycle for a couple of seconds.

Maybe I need to activate the pre-charging in the BMS-Settings?
In the BMS Tool I found in the tab "BMS Control" a section labeled "Charge OCP Model" with the following possible radio-button options:

• No Current Limit Protection (this is activated!)
• Current Limiting Charging
• Precharge Protection
• After Charging Limit
• Precharge+Charge Limit

I wonder if the wording Precharge in this "Charge OCP Model" section is what I'm looking for? Do I need to activate it manually?


So the important questions in short are:

Does the EG4-LL (V2) has a pre-charge resistor and cycle mechanism at all?
Do I need to enable it in the BMS settings or should it be just there?
Is the same pre-charge sequence used for the EG4-LL (V2) batteries like described for the LifePower4?
Is it ok to not see LED's cycling and no clicking noise like the LifePower4 does or should this happen also with the EG4-LL (V2)?
Does the pre-charge cycle happen even if no inverter is connected (I'm aware, that it would not charge anything even, if the cycle would happen)?

Thanks!

 

[timselectric]

Turn on everything else before turning on the battery breaker.

 

[fmeili1]

Turn on everything else before turning on the battery breaker.

Thanks, that sounds easy. Do you get visual and/or acoustic feedback on the EG4-LL (V2) while pre-charge cycle runs (like the LifePower4 does)?

 

[timselectric]

Not sure.
I don't have one.

 

[fmeili1]

There is something not like it should. Today, I used all 6 inverters in parallel (no load, just idle consumption) for the first time in the following startup order:

1. Switched all external battery breakers ON (breakers between bus bar and inverters)
2. Switched all 9 batteries ON with their BMS switches (breakers in front of the batteries are still OFF)
3. Switched ON the first breaker on the first (master) battery and it ended up with a fault (over current protection)
4. Switched all 8 other breakers in front of all other batteries to ON (no more faults)
5. Switched the 1st battery OFF and back to ON and no more fault

This behavior looks like there was no pre-charging and current limitation involved. So I think the pre-charging resistor in the EG4-LL V2 does NOT work like in the LifePower4 (just by using the integrated battery breaker). Next time I will try to switch the battery integrated breaker first and the BMS switch as last to see if the behavior will be different (maybe the LL V2 pre-charging is initiated with the BMS switch and no with the integrated breaker?).

Does anybody really know if and how the pre-charging resistor functionality is working with the EG4-LL V2 batteries?

 

[timselectric]

There is something not like it should. Today, I used all 6 inverters in parallel (no load, just idle consumption) for the first time in the following startup order:

1. Switched all external battery breakers ON (breakers between bus bar and inverters)
2. Switched all 9 batteries ON with their BMS switches (breakers in front of the batteries are still OFF)
3. Switched ON the first breaker on the first (master) battery and it ended up with a fault (over current protection)
4. Switched all 8 other breakers in front of all other batteries to ON (no more faults)
5. Switched the 1st battery OFF and back to ON and no more fault

This behavior looks like there was no pre-charging and current limitation involved. So I think the pre-charging resistor in the EG4-LL V2 does NOT work like in the LifePower4 (just by using the integrated battery breaker). Next time I will try to switch the battery integrated breaker first and the BMS switch as last to see if the behavior will be different (maybe the LL V2 pre-charging is initiated with the BMS switch and no with the integrated breaker?).

Does anybody really know if and how the pre-charging resistor functionality is working with the EG4-LL V2 batteries?

I forgot that the LL has a separate BMS power switch.
The pre-charge is part of the BMS startup sequence.
So yes, it would be breaker first then BMS power switch.
Not sure if one pre-charge can handle 6 units starting at the same time. I don't remember if all BMS's startup when the master does.

 

[fmeili1]

I forgot that the LL has a separate BMS power switch.
The pre-charge is part of the BMS startup sequence.
So yes, it would be breaker first then BMS power switch.
Not sure if one pre-charge can handle 6 units starting at the same time. I don't remember if all BMS's startup when the master does.

Ok, thank's for confirming this. I'll try this by end of the week.
Btw. Each battery BMS must be switched on by itself, it does not autostart the others when starting the master.

 

[timselectric]

Ok, thank's for confirming this. I'll try this by end of the week.
Btw. Each battery BMS must be switched on by itself, it does not autostart the others when starting the master.

Easy enough to turn them on manually, at the same time. Or one after another, quickly.

 

[fmeili1]

I forgot that the LL has a separate BMS power switch.
The pre-charge is part of the BMS startup sequence.
So yes, it would be breaker first then BMS power switch.
Not sure if one pre-charge can handle 6 units starting at the same time. I don't remember if all BMS's startup when the master does.

Even when using the BMS power switch, the battery (the first which is switched on) will go in fault (over current). So I don't know if there exists really a pre-charge mechanism in the EG4-ll (V2) OR it's even with pre-charge mechanism too much current for 9 batteries.

 

[timselectric]

Even when using the BMS power switch, the battery (the first which is switched on) will go in fault (over current). So I don't know if there exists really a pre-charge mechanism in the EG4-ll (V2) OR it's even with pre-charge mechanism too much current for 9 batteries.

I guess that the other batteries aren't getting to the pre-charge mode fast enough to help the first one.
I know that I sometimes have issues trying to start up 3 Growatt's at the same time. With one Lifepower4 battery. I don't normally do it that way.
Usually I have all batteries on, and bring the Growatt's online one at a time.
Those capacitors take a lot of current, if allowed to.
And even though it's only for a half a second. It's enough to trip a BMS, easily.

 

[Koldsimer]

One workaround is to use your scc to help with charging the capacitors in the inverter. Turn of all loads that your inverter may power then use the scc to help. I know it's not recommended by most inverter manufacturers, but it was the only way i got my eg4 lifepower batteries to start my inverter (schneider xw pro 6848).

Even though you're using the eg4 ll v2, this may work for you.

Also, according to at James SS, the pre-charge resistor functions every time you turn the battery on.

 

[cdsolar]

So, does the EG4 LLv2 actually have a pre-charge resistor? (I'm interested in the 48v UL model specifically).

 

[timselectric]

So, does the EG4 LLv2 actually have a pre-charge resistor? (I'm interested in the 48v UL model specifically).

Yes

 

[ePowerBank]

@fmeili1 Did you ever sort out your "power-on" sequence?

I too have same question as I'm starting up new EG4-LL (V2) for first time, and also noticed new EG4-LL instructions don't mention like prior model.
So I phoned Signature Solar tech support and was told that EG4-LL does have built-in resistor, and use following power-on sequence:
1 - DC breaker
2 - EG4-LL Battery breaker
3 - EG4-LL Battery ON/OFF push button
4 - Solar (if applicable)
5 - AC (if applicable)
6 - Inverter

Also told to follow same order for powering down.

I'm curious what experienced users are doing?
Did I waste my money buying resistor(s)?
If people are using resistors, I'm curious how it fits in the sequence?

 

[Rusty959]

I have the 18kpv and 3x LLs.

Most importantly, the battery, before turning it on with the power button (on the left) MUST be connected to whatever is being charged, generally the inverter. It's not connected if ALL breakers aren't on. When the battery turns on and you see all the startup stuff on the screen, it will check voltages and do precharge if needed.

My process:
Connect everything with all breakers turned off. Inverters, batteries, etc.
While powered off, turn on ALL breakers, including batteries and inverters.
Power on the master LL battery and allow it to go through the startup sequence. Your inverter if not already on will power up.
Turn on the rest of the batteries at any rate or order you choose, it doesn't matter since the system is already charged.

Keep in mind once one battery is on and connected everything is charged. If you have powered up a battery and THEN turn on the breakers it's no different for the LL from turning on everything and just touching terminals which is why you got the overcurrent protection.

 

[wdwtx2.0]

As per EG4 6000EX manual: (In section about commissioning system)
Step 9 - Turn on the system's DC breaker (between inverter and batteries if equipped), all battery breakers and/or power buttons, and power on the inverter. (in that exact order)
Step 10 - Switch on all AC in breakers.
Step 11 - Ensure PV voltage meets specifications on page 9. Turn on PV power.
Step 12 - Switch on all AC out breakers

Has always worked for me (so far).