Need Help Setting up Schneider Conext SW with EG4 Battery

[Old_Skewler]

I have a XW6848pro with some screenshots - I followed the signatureSolar youtube guide to add BMS with upgraded firmware and appears to be working propert

Beautiful installation, it looks very clean. I want to ask you many questions about the wiring but let me first focus on the Conext programming.

Few questions I would like to ask you:

1. did you get the proper network cable from Signature Solar? I was told there is a link to request that cable. Could you send me the link?
2. Where did you get the proper EG4-LP firmware to use with the Schneider? When I went to their website I was not able to find it. The only EG4 firmware upgrade found under their site does not match the firmware listed under the video.
3. Why under "Battery Setting" you have "SOC Control" disabled? I thought the final goal would be to have SOC control over the battery but it seems like you are not using it? Could you please clarify?

Thank you in advance!

 

[BentleyJ]

I understand a battery monitor or battery communication (BMS) would be ideal, but until I get there, how else should I monitor battery level other than voltage?

Unfortunately, we are both in the same situation, I don't have a whole system shunt either. While not ideal voltage is still useful as a rough guide to battery SoC.

I do not understand how the charger current settings disappeared, but you are correct, the "Max Charge Rate" controls the current. At 50% I get about 25 amps. I am currently running at 80%, which gives me about 36 amps - my memory/numbers could be off a bit but the general concept is correct.

Excellent so that setting is working as expected.

I am not sure I fully understand what that means. Shouldn't they match, AGS Triggers & Recharge Voltage? What would happen if Recharge Voltage is HIGHER than AGS Trigger? Or vice-versa? I currently have recharge voltage set at 52V & AGS trigger at 51V.

Perhaps I'm mistaken. I thought your only means of charging was the generator. Do you also have a utility AC input? In any case, the AGS and the Inverter are separate devices. The Recharge Voltage setting on the Inverter is the setting for when the internal charger will turn on and recharge the batteries from an AC source but there is no AC source when the gen is off so basically nothing happens until the gen comes on at 51V. I agree with you it does make sense to have them both set at the same voltage. So maybe 51V for each. The other issue that could come up is the opposite of this scenario. What would happen if the AGS were set to 52V but the Inverter were set to 51V. Would the Gen start but not charge until the batteries got all the way down to 51V? I believe the answer is NO because the Schneider (at least this is how my XW+ works) initiates a recharge cycle whenever an AC source becomes available after there was an interruption regardless of battery voltage.

I have the AGS Trigger Auto ON/OFF based on DC voltage and it seems to be working after I went thru an entire 51V > 55.6V cycle at 85% current (36 Amps). I don't want to experiment too much out of the basics, unless it is confirmed that I have a wrong setting.

Good to hear this is working well. Ya don't change it then.

 

[Old_Skewler]

Here are the latest settings that I will try for the next couple of days:

CONEXT SETTINGS_INVERTER
Maximum Charge Rate: 75%
Bulk/Boost Voltage Set Point: 56.8V
Bulk Termination Voltage: 56V
Absorption Voltage Set Point: 56V
Recharge Voltage: 52V
Low Battery Cut Out: 47V
High Battery Cut Out: 58V

CONEXT SETTINGS_AGS
Starting Battery Voltage: 51V
Stop Voltage: 55.6V

 

[BentleyJ]

You are correct, I am currently charging off a generator and would like to find that sweet spot between charging current & voltages and generator runtime.

Follow up question: how does one actually know that the voltage is too high? What are the symptoms or side effects that I should be on the look out for?

I am setting it to 56.8V & 56V as recommended as a starting point, to be on the safe side.

If your voltage gets too high like into the 57.6 V and above range it can trigger a BMS shut down. You definitely don't want that.

 

[Old_Skewler]

Unfortunately, we are both in the same situation, I don't have a whole system shunt either. While not ideal voltage is still useful as a rough guide to battery SoC.

Got it! My plan is to eventually get a Schneider Battery Monitor next spring when I will also add more battery capacity. Until then i'll be messing with the voltages.

I also hope to be able to eventually connect the EG4 to the Conext via BMS - just waiting for Signature Solar to get their shit together and provide the correct firmware and steps to get this done.

Perhaps I'm mistaken. I thought your only means of charging was the generator. Do you also have a utility AC input? In any case, the AGS and the Inverter are separate devices. The Recharge Voltage setting on the Inverter is the setting for when the internal charger will turn on and recharge the batteries from an AC source but there is no AC source when the gen is off so basically nothing happens until the gen comes on at 51V. I agree with you it does make sense to have them both set at the same voltage. So maybe 51V for each. The other issue that could come up is the opposite of this scenario. What would happen if the AGS were set to 52V but the Inverter were set to 51V. Would the Gen start but not charge until the batteries got all the way down to 51V? I believe the answer is NO because the Schneider (at least this is how my XW+ works) initiates a recharge cycle whenever an AC source becomes available after there was an interruption regardless of battery voltage.

You are correct, I only have one generator as AC source. And I agree with the explanation and will set both to 51V. This makes more sense now.

 

[BentleyJ]

Here are the latest settings that I will try for the next couple of days:

CONEXT SETTINGS_INVERTER
Maximum Charge Rate: 75%
Bulk/Boost Voltage Set Point: 56.8V
Bulk Termination Voltage: 56V
Absorption Voltage Set Point: 56V
Recharge Voltage: 52V
Low Battery Cut Out: 47V
High Battery Cut Out: 58V

CONEXT SETTINGS_AGS
Starting Battery Voltage: 51V
Stop Voltage: 55.6V

That looks good. Per the previous post feel free to set the AGS and Recharge Volts to the same value. Actually 51V is a good setting for both, that calculates out to 3.1875V per cell so you are definitely not over discharging and the generator is not cycling on and off.

 

[Old_Skewler]

If your voltage gets too high like into the 57.6 V and above range it can trigger a BMS shut down. You definitely don't want that.

Got it! If I was able to get a full cycle at 57.6V before and that saves me on generator runtime, should I keep it?

 

[BentleyJ]

Got it! If I was able to get a full cycle at 57.6V before and that saves me on generator runtime, should I keep it?

I think that falls into the category of a decision you have to make based on your set up. As the battery ages the cells will drift out of balance and the BMS will correct the imbalance but it does so with a small currents between cells. It needs some time to accomplish this task. If your charge cycles are too short then your high charge C rate is degrading the batteries faster and complete rebalancing is not happening. Eventually you will get a cell that exceeds the BMS threshold value and the BMS will disconnect. Its not really good for the system if the battery disconnects abruptly with current flowing.
You definitely need to monitor the BMS especially the individual cell voltages during the end of the charge cycle to make sure they are staying balanced.

 

[Old_Skewler]

You definitely need to monitor the BMS especially the individual cell voltages during the end of the charge cycle to make sure they are staying balanced.

How does one do that? And how do you determine the proper charge rate for these batteries? I see you mentioned 0.2C & 0.1C... how did you determine these things?

 

[BentleyJ]

How does one do that? And how do you determine the proper charge rate for these batteries? I see you mentioned 0.2C & 0.1C... how did you determine these things?

I scrolled back through the previous posts and noticed the particular model of EG4 you are using does not have the built in monitoring display. I was under the impression that Signature Solar had a stand alone device that could be connected to the BMS to get the internal info. Perhaps a Bluetooth module and app.

As far as the charge rate for LiFePO4 chemistry is a generally recognized industry standard that 0.2 to 0.3C charge rates prolong the life of the cells and reduce the tendancy for swelling. I've only had batteries in operation for about 4 years so I don't have any really long term experience with battery life vs. charge rates. What I can say is so far everything is working quite well with no problems so that leads me to believe the settings I'm using are proper.

 

[hammick]

Charger Settings:

Charge Cycle = 2 Stage (normally LiFePO4 does not need float and is considered detrimental if used continuously. At times I have used the float setting at low amperage over several hours to give the active cell balancer time to top balance when needed, like once every few months.)
Maximum Charge Rate =100% (is OK to leave this at 100% (45A) on this setting since it can be reduced in the Bulk and Absorption settings)
Equalize = Disable
Charger Override = Disable
Default Batt Temp = Warm
Bulk Voltage Set Point = 55V to 56V (This stage is also referred to as constant Current charging)
Max Bulk Chg Current = 20A to 30A (This is a 0.2C to 0.3C rate for the battery you have)
Bulk Termination Voltage = 0.8V lower than Boost Voltage Set Point, per manual.
Bulk Termination Time = 180 to 240 sec
Absorption Voltage Set Point = 55V to 56V (Given enough time the battery will reach over 95% SoC at 3.4V per cell, This stage is also referred to as constant Voltage charging)
Max Absorption Chg Current = 20A to 30A
Absorption Time = 120 to 180 min (This cycle may terminate early if the battery is charged and the current drops off to near 0)
Float Voltage Set Point = 54.4V to 54.8V (This setting is not active because we are using 2 stage charging but if you ever turn on 3 stage charging the settings are already correct)
Max Float Chg Current = 5A to 10A (This setting is only active when 3 stage charging is selected)
Charge Block (can be used to disable charging for example during certain times of the day were utility rates are higher. Leaving it as is basically disables the feature until new values are selected.)

Wouldn't float be a good idea if you only charge to 80% to keep the charge cycles down for maximum life? (bulk absorb and float all at 54.4v)

Without float I could see burning through two or more charge cycles a day.

 

[BentleyJ]

Wouldn't float be a good idea if you only charge to 80% to keep the charge cycles down for maximum life? (bulk absorb and float all at 54.4v)

Yes, this scenario would work.

Without float I could see burning through two or more charge cycles a day.

That post, if I remember correctly-been a while, is in response to a specific use case for that forum member. With Schneider inverters there is no built in Solar Charge Controller(s), they are separate. Therefore the settings for the solar charge controller, if any, and inverter charger may or may not be the same. Those settings were for the Inverter specifically.

There are 2 broad scenarios with solar storage batteries that would dictate different charge methods.
1) Back-up only for utility outages where the batteries are basically sitting virtually idle or in standby with only the parasitic loads from the inverter and BMS. Typically float would not be used continuously or the voltage would be set very low 54.4 or less.
2) Daily or frequent use of the batteries and inverter to offset utility usage, reduce Time-of-Use billing charges during certain seasons and time of day, Sell Back or even off-grid then for sure Float would be enabled so the solar charge controllers stay active and produce as much energy as possible.