Schneider CSW4024 Battery Charging Fault

[Nitr0]

So now that I have the powerblock in use and charging appropriately does anyone know how to get the Conext Battery Monitor to read the proper SOC for the battery? I synchronized it after the battery dropped down to its normal 26.7v but a full charge only ever puts the SOC back to 62-67%. I went and verified all my settings for the battery monitor against settings I could find on Youtube tutorials but same result. Also shows the wrong percentage when in use compared to what I believe the DoD is for the block. This is what I've been going off of.

80% - 27.2v
60% - 25.6v
40% - 24v
20% - 22.4v

 

[GVSolar]

So now that I have the powerblock in use and charging appropriately does anyone know how to get the Conext Battery Monitor to read the proper SOC for the battery? I synchronized it after the battery dropped down to its normal 26.7v but a full charge only ever puts the SOC back to 62-67%. I went and verified all my settings for the battery monitor against settings I could find on Youtube tutorials but same result. Also shows the wrong percentage when in use compared to what I believe the DoD is for the block. This is what I've been going off of.

80% - 27.2v
60% - 25.6v
40% - 24v
20% - 22.4v

View attachment 40938

Here's another chart that looks at SOC differently - one that I more closely adhere to.

 

[GVSolar]

And all those numbers depend on whether the battery is under charge/discharge, at rest (for how long) and general condition/balance of the battery. YMMV, but I tend to go with more conservative numbers.

 

[GXMnow]

I am not using the Schneider Battery Monitor in my system, so I don't have any hands on time with one. With your battery bank being LFP, using the voltage to estimate the state of charge is not very accurate. You can easily have a 20% charge in state of charge with basically no change in voltage. The battery monitor actually counts the amp hour going in and out of the battery to get a more accurate estimate of the true state of charge.

From the manual, you do need to tell it your actual battery capacity. If you are not full cycling, it is common to set this a little smaller, so 20% is 20% of what you want to use, not 20% of the maximum. You also need to input the float charge voltage. Since you are running LFP, set this to your absorb volts. The default reading when you power up the battery monitor should be 75%. Then you fully charge the battery and then do the synchronization. With a fully charged battery, you hold the left and right arrows in for three seconds, and the display should change to "Full". At that point it should read 100% and count down correctly. It can auto synchronize each time the battery reaches full charge, but for that to work, several settings need to be correct to match your charging settings. These are under the "System Properties Settings" menu. The first entry F1.0 is "Charger's Float Voltage", or in your case, absorb voltage, or maybe the voltage the cells rest back to after absorb cuts off. This might be an issue as it seems the instruction are written for lead acid. I would think setting this to 3.4 volts per cell x 8 in your case = 27.2 volts should work. The next value is the float current. Again, you should not be running any float current on LFP cells. This value is a percentage of battery capacity. Current has to fall below this number, with the battery above the float volts. Your pack is 170 amp hour, so setting this to 5% would mean it has to see charge current fall below 8.5 amps while in absorb mode. You might have to experiment to see what works well on your system. The third value is "Auto Sync Time". It has to see volts above the first, and current under the second for this amount of time, then it will reset to 100% full. Try 60 seconds and see if it will auto sync next charge cycle. The 4th value is the discharge floor. This is the bottom percentage of your amp hour capacity where you want the battery monitor to go to zero remaining. The default with lead acid is 40%. You can safely go down to 20% on your LFP system. The next 2 are battery temp averaging and your time remaining filter settings. Then the 7th value (F1.6) is "Auto Sync Sensitivity". It just has a range of 1-10 with 5 being the default. A lower value will allow it to trigger a resync quicker. But if it resets too often, raise it to slow it down.

I have thought about getting one of these so the XW-Pro would have a better idea of my battery state of charge, but as it turns out, my NMC cells have a nice voltage slope, so working off of voltage alone is pretty good. This is very different than LFP cells. My voltage goes from 51 to 57 volts in 6 hours of charging, and is nearly linear at my slow 26 amp charge rate. But I am curious if you do get the Batt Mon working right, how well does it track. I may still add it to get the amp hour data and state of charge into my Insight monitoring. Now I have to go into my garage and use the Blue Tooth app on my BMS.

 

[Nitr0]

Here are all the settings that Schneider had me set. I'm going to go back over all the values with what you stated above. My question from the start is setting the sync. Schneider had me set the sync at the battery top end when the bulk stopped. Thats why I think it settled down from 100% to 67%.

Charger Settings
Charge Cycle:		2 Stage
Force Charger State:		No Float
Max Charge Rate:		20%
Bulk/Boost Voltage:		28.8v
Max Bulk Charge Current:
Bulk Termination Voltage:		28v
Bulk Termination Time:		180s
Absorption Voltage Set Point:		27v
Max Absorption Charge Current:
Absorption Time:		1 min
Float Voltage Set Point:		26.6v
Max Float Charge Current:
Battery Settings
Battery Type:		Custom
Battery Bank Capacity:		170
Battery Temperature Coefficient:		-54
Recharge Voltage:		25v
Low Battery Cut Out:		23v
Low Battery Cut Out Delay:		10s
Low Battery Cut Out Hysteresis:		2v
High Battery Cut Out:		31
Battery Monitor
Charger Settings
Charger Float Voltage		26.6v
Charger Float Current		2%
Discharge Floor		20%
Auto Sync Time		240
Auto Sync Sensitivity		5
Battery Settings
Nominal Temp		20 C
Temp Coefficient		0.5
Nominal Discharge Rate		20
Self Discharge		0
Shunt Rating		500
Shunt Voltage		50
Charger Efficiency Factor Mode		Enabled
Nominal Voltage		24
Time Remaining Average Filter		Faster
Default Temp		26
Battery Capacity		170
Peukert Exponent		1

 

[Nitr0]

And thank you for the voltage chart.

 

[Nitr0]

Also, I don't have an SCP (forever backordered everywhere) so all the settings are basically how they appear in the Conext Gateway (InsightLocal)

 

[Nitr0]

Ok, so I read back over the proposed settings and the voltage chart and here is what I've come up with. Let me know where I've messed up as its been a long windy day here.

Charger Settings
Charge Cycle:	2 Stage
Force Charger State:	No Float
Max Charge Rate:	20%
Bulk/Boost Voltage:	28.8v
Max Bulk Charge Current:
Bulk Termination Voltage:	27.2v
Bulk Termination Time:	60s
Absorption Voltage Set Point:	27.2
Max Absorption Charge Current:
Absorption Time:	1 min
Float Voltage Set Point:	26.6v
Max Float Charge Current:
Battery Settings
Battery Type:	Custom
Battery Bank Capacity:	170 Ah
Battery Temperature Coefficient:	-54
Recharge Voltage:	26.2v
Low Battery Cut Out:	23v
Low Battery Cut Out Delay:	10s
Low Battery Cut Out Hysteresis:	2v
High Battery Cut Out:	31v
Battery Monitor
Charger Settings
Charger Float Voltage	26.6v
Charger Float Current	2%
Discharge Floor	20%
Auto Sync Time	60s
Auto Sync Sensitivity	5
Battery Settings
Nominal Temp	20 C
Temp Coefficient	0.5
Nominal Discharge Rate	20
Self Discharge	0
Shunt Rating	500
Shunt Voltage	50
Charger Efficiency Factor Mode	Enabled
Nominal Voltage	24
Time Remaining Average Filter	Faster
Default Temp	26
Battery Capacity	170
Peukert Exponent	1

 

[Nitr0]

My other question is what is the difference in these values? Which is my actual bulk voltage that should be 28.8v

Bulk/Boost Voltage:	28.8v
Bulk Termination Voltage:	27.2v

 

[GXMnow]

Yeah.... I questioned Schneider about that too. My Bulk Termination voltage is maxed out at just 54 volts in the custom menu, but my Bulk Boost let me dial it up and I am currently at 57.2 on my 14S NMC pack. Same with Absorption Voltage 57.2 volts. For some reason, they felt the Bulk Charge should stop short, and going higher is called a Boost Charge.

I am running no float but the float voltage is 56.7volts. On LFP, that might come into play as they do settle back down when the charge completes, but my NMC cells only lose a few millivolts if they sit for days. Overnight, I don't see any change in the 2 decimal places. I have it set to stop exporting power at 51 volts, the battery summary stops at 50.94 volts, and 10 hours later, it is still 50.94 volts. My system charges from 9 am to about 3 pm. Today, it terminated at 57.19 volts at 2:54 PM, The absorb only lasted 3:10 PM where it fell under 8 amps, and the voltage ticked up to 57.21 volts. It only sat at no load to 4:33 pm where I started exporting as the solar fell off. The battery voltage was still sitting at 57.21 after well over an hour at zero current.

For your 8S LFP pack, your numbers look pretty good.
The 27.2 volts is 3.4 per cell, that is a good resting point for LFP.
The Bulk/Boost Voltage going to 28.8 works out to 3.6 volts per cell. I would not go any higher.
Bulk termination time, and absorption time of just a minute seems a little short. Might want to give that a bit more time to get the cells to top up together as the BMS balances. Try maybe 15 minutes.

I searched a lot, and I could not find a temp coefficient. Everyone just says set it at Zero for lithium batteries. Mine does not have an entry for Peukert Exponent. That is also much better on lithium compared to lead acid batteries. Just using 1 should be good.

 

[Nitr0]

Thanks again for all the information. I'm going to make some of the recommended adjustments and test in the morning.

 

[Nitr0]

So here is the feedback I got from Schneider since they are finally responding to my case.

"During the Bulk Voltage, the battery voltage will increase from the Bulk/Boost Voltage to the Bulk Termination Voltage where the Absorption Stage starts.

Please be sure the batteries are 100% charged when you Sync the Battery Monitor. We will suggest performing a charge cycle before synchronizing."

My charging worked fine with all the settings adjusted up just a little to Bulk/Boost of 29.2v, Bulk term of 28.8v and absorb of 27.2v as Schneider had me adjustment. Then it all stopped working again on my second rundown and charge. They had me raise the HBCO but it still failed then they sent me this.

"In order to prevent any damage to the batteries, you should contact your battery distributor to check all the battery specifications.

In my opinion, 10 minutes for the absorption stage is too low compare with the normal 180 min other Li-ion batteries used to manage. Please check all the battery specifications carefully.

We are afraid we can not help you furthermore from here."

I've just turned everything back down to how it was discussed previously in the forum with Bulk/Boost of 28.8v, Bulk term of 27.2v and absorb of 27.2v

 

[GXMnow]

Schneider tech support is not very good. (being nice)

Going by the battery specs you posted back at the beginning of this thread, here is what I would suggest...

Custom
2 stage no float
Bulk/Boost Voltage Set Point 28.4 volts (this is 3.55 volts per cell, which is still 99% full on LFP)
Absorption Time 3,600 seconds (1 hour seems plenty on Lithium cells)
Absorption Voltage Set Point 28.4 volts
Float Voltage Set Point 26.4 volts (The cells should not settle this low, 3.3 volts per cell) Float is turned off anyways.
Bulk Termination Voltage What is the limit? 28.0 volts would be good, but it probably won't go that high
Bulk Termination Time Mine is set to just 10 seconds. When the cells reach full voltage, we want to reduce the current fairly quick.
Absorption Period Timeout 60 minutes (1 hour again, seems good, mine is typically done in 20 minutes)

For the battery monitor, try these settings
f1.0 Charger Float Voltage 27.2 volts (that is 3.4 per cell which is where LFP cells tend to rest after a charge)
f1.1 Charger Float Current Try 10% The current has to fall below this value for the battery monitor to sync. 10% of 170 Amp Hours is 17 amps.
f1.2 Auto Sync Time The default if 4 minutes, try dropping it to 60 seconds, 1 minute to see if that helps it sync up.
f1.3 Discharge Floor How low do you want to run your batteries? 50% for lead acid is normal, with LFP you can safely go down to 20%
f1.4 Battery Temperature Set this to the temperature where the battery is. It has basically no effect on lithium cells
f1.5 Time Remaining Averaging Filter As loads change it calculate how long you have until the battery runs out. How fast do you want this
to move? It only has 3 settings, 1 is the middle, 0 faster, 2 slower
f1.6 Auto-Sync Sensitivity Default is 5, going lower will more likely trigger an auto sync, higher will make it take longer to auto sync.

f2.0 Battery Capacity The logical choice is 170 Amp Hours, but you might need to lower it a bit to get accurate readings.
f2.1 Nominal Discharge Rate At what rate are your cells spec'd? 20 hour is normal for lead acid, with LFP, 5 hour is probably closer.
f2.2 Nominal Temperature +20C is probably good, but does not matter much, this is for temp compensation, and LFP zero comp
f2.3 Temperature Coefficient Set this very low or even off. LFP cells don't lose capacity as long as they stay above freezing.
f2.4 Peukert's Exponent 1 is normal for LFP, but we might get slightly more accurate readings at high loads with a slight increase here.
I have found people recommending 1.01 to 1.03 on good cells. The higher the current draw, you do lose a little capacity
f2.5 Self Discharge Rate This only matters if the system sits with no load. How much does it lose per month. Off or a small number for LFP
f2.6 Charge Efficiency Factor My cells measured 98% This is how many Amp Hours you get out, for each Amp Hour charged in.

Hopefully that should work for you.

 

[GVSolar]

FWIW - Some thoughts about using float/no float from @Steve_S . Since I'm 100% off-grid I am a "floater". Best.

 

[GVSolar]

Oops. Forgot this:

You have Absorb at 56.4V - 3.525 per cell. Of course you will get HVD, cells WILL run above 3.450 and there is always one.
Try these settings to see what happens,
Absorb: 56.0 (3.500 per cell)
Float: 55.8 (3.487 per cell) YES FLOAT - Constant Voltage - variable amp pending on draw.
Re-Bulk / Re-Absorb: 55.40 (3.46 per cell)
EQ - OFF
Cutoffs: Hi = 58.40, Lo = 41.6

Voltage Cuve IS 3.000-3.400 where the majority of power lives. Above 3.5 and below 3.0 only represents <10% of capacity which we normal prefer to reserve anyways for longevity & maximum cycles.

BMS settings:
If possible set a 10-second delay for LVD Cutoff as a surge demand could pull cells below cutoff momentarily due to voltage drop.
20mv differential is between cells is quite comfortable for them. They can diverge as much as 1mv per AH capacity, so be aware of that, this is usually in the "runner space".

Bulk/Absorb is High Current and will charge you to 80-85% with little issue but once your close to the top Constant Voltage (float) is the key to get the cells up to full "gently". Even EV Systems do this internally for charging ! The top 15% is slowed to prevent runners and out of balance as a result.

Float will also keep feeding your inverter demand as long as the solar watts/amps are available.
My Battery bank reaches 100% and SCC goes to float, I turn on my coffee maker which is drawing 50A, the SCC will provide that 50A while the battery bank get's 1A on trickle. Coffee pot finishes and if ANY battery power was used, it may rebulk or renter float to top off and then it will only feed what my inverter is demanding + a little as the battery cells in the packs balance, they draw a little as needed. Since implementing the use of float and these parameters I have NOT seen an HVD, all packs come up to 3.48-3.49 per cell happily and level out to 10mv diff.

Specifics:
I use Passive Balancing ON during Charge allowing for 30mv difference starting at 3.300v per cell. Courtesy of Chargery BMS.
I also have a QNBBM Active Balancer on every pack and that does take care of levelling up the cells as well, it is observable & tangible.
I am using EVE 280's Bulk Cells & used 175AH EV Grade LFP. All have been Top Charged & Top Balanced.

 

[GVSolar]

Also this from @Steve_S :
One REALLY IMPORTANT THING: Make sure your system is Calibrated, so when you look at the battery voltage at the terminals which say 50.0V that the Inverter & SCC also see it as 50.0V or have compensation for it. Best to check this when there is 0 Load, then with a moderate Load say of 20A, then again when a charge is happening. If the Inverter or SCC are not matched up to read the voltages properly, they can over/under perform resulting in problems.

FLA is less picky and 0.1 or 0.5V wouldn't make much difference but with anything Lithium that has a BMS the devil IS in the details and precision is a must. So many people just ignore calibrating their gear and wonder why stuff happens...

Contained in this discussion:

You do not need a high current balance current or "active balancer". Here is more proof

While I agree with several sentiments I do NOT fully agree with everything. 1) New "Matched & Balanced" cells do not diverge much and more often than not Passive Balancing is more than sufficient. 2) Bulk/Commodity cells tend to diverge more at both the Top (above 3.40 and below 3.00). I...

diysolarforum.com

 

[Steve_S]

Also this from @Steve_S :
One REALLY IMPORTANT THING: Make sure your system is Calibrated, so when you look at the battery voltage at the terminals which say 50.0V that the Inverter & SCC also see it as 50.0V or have compensation for it. Best to check this when there is 0 Load, then with a moderate Load say of 20A, then again when a charge is happening. If the Inverter or SCC are not matched up to read the voltages properly, they can over/under perform resulting in problems.

FLA is less picky and 0.1 or 0.5V wouldn't make much difference but with anything Lithium that has a BMS the devil IS in the details and precision is a must. So many people just ignore calibrating their gear and wonder why stuff happens...

Contained in this discussion:

You do not need a high current balance current or "active balancer". Here is more proof

While I agree with several sentiments I do NOT fully agree with everything. 1) New "Matched & Balanced" cells do not diverge much and more often than not Passive Balancing is more than sufficient. 2) Bulk/Commodity cells tend to diverge more at both the Top (above 3.40 and below 3.00). I...

diysolarforum.com

LOL, I'm a ghost hehehe...
There is a link in my Signature for LFP Voltage Chart & on Calibrating your systems
Now visible to anyone looking for them.

 

[Nitr0]

Schneider tech support is not very good. (being nice)

Going by the battery specs you posted back at the beginning of this thread, here is what I would suggest...

Custom
2 stage no float
Bulk/Boost Voltage Set Point 28.4 volts (this is 3.55 volts per cell, which is still 99% full on LFP)
Absorption Time 3,600 seconds (1 hour seems plenty on Lithium cells)
Absorption Voltage Set Point 28.4 volts
Float Voltage Set Point 26.4 volts (The cells should not settle this low, 3.3 volts per cell) Float is turned off anyways.
Bulk Termination Voltage What is the limit? 28.0 volts would be good, but it probably won't go that high
Bulk Termination Time Mine is set to just 10 seconds. When the cells reach full voltage, we want to reduce the current fairly quick.
Absorption Period Timeout 60 minutes (1 hour again, seems good, mine is typically done in 20 minutes)

For the battery monitor, try these settings
f1.0 Charger Float Voltage 27.2 volts (that is 3.4 per cell which is where LFP cells tend to rest after a charge)
f1.1 Charger Float Current Try 10% The current has to fall below this value for the battery monitor to sync. 10% of 170 Amp Hours is 17 amps.
f1.2 Auto Sync Time The default if 4 minutes, try dropping it to 60 seconds, 1 minute to see if that helps it sync up.
f1.3 Discharge Floor How low do you want to run your batteries? 50% for lead acid is normal, with LFP you can safely go down to 20%
f1.4 Battery Temperature Set this to the temperature where the battery is. It has basically no effect on lithium cells
f1.5 Time Remaining Averaging Filter As loads change it calculate how long you have until the battery runs out. How fast do you want this
to move? It only has 3 settings, 1 is the middle, 0 faster, 2 slower
f1.6 Auto-Sync Sensitivity Default is 5, going lower will more likely trigger an auto sync, higher will make it take longer to auto sync.

f2.0 Battery Capacity The logical choice is 170 Amp Hours, but you might need to lower it a bit to get accurate readings.
f2.1 Nominal Discharge Rate At what rate are your cells spec'd? 20 hour is normal for lead acid, with LFP, 5 hour is probably closer.
f2.2 Nominal Temperature +20C is probably good, but does not matter much, this is for temp compensation, and LFP zero comp
f2.3 Temperature Coefficient Set this very low or even off. LFP cells don't lose capacity as long as they stay above freezing.
f2.4 Peukert's Exponent 1 is normal for LFP, but we might get slightly more accurate readings at high loads with a slight increase here.
I have found people recommending 1.01 to 1.03 on good cells. The higher the current draw, you do lose a little capacity
f2.5 Self Discharge Rate This only matters if the system sits with no load. How much does it lose per month. Off or a small number for LFP
f2.6 Charge Efficiency Factor My cells measured 98% This is how many Amp Hours you get out, for each Amp Hour charged in.

Hopefully that should work for you.

So this confuses me...

For the battery monitor, try these settings
f1.0 Charger Float Voltage 27.2 volts (that is 3.4 per cell which is where LFP cells tend to rest after a charge)

If I'm already set to float disabled in the inverter, shouldn't this be set to 26.4v like I have on the inverter?

 

[GXMnow]

So this confuses me...

For the battery monitor, try these settings
f1.0 Charger Float Voltage 27.2 volts (that is 3.4 per cell which is where LFP cells tend to rest after a charge)

If I'm already set to float disabled in the inverter, shouldn't this be set to 26.4v like I have on the inverter?

The battery monitor is only using this value to compare to the battery voltage. The battery needs to go above this "Float Voltage" to detect that it has reached a full charge state. It will "Sync" to 100% state of charge when the current falls below the float current while the voltage is above the float volts. Setting this lower might allow it to r-sync quicker, but I don't know what effect it will have if it is set too low. The battery won't settle back down that low until there is a load on it. So you may need to experiment on it to get it to reliable auto sync after each full charge.

 

[GXMnow]

Now this is interesting....

I was just watching a cool video from Jehu Garcia with EV West converting a Karman Ghia to electric power. And they installed a Xantrex Battery monitor. It is a little different than the Schneider Conext Battery Monitor, but it seems to be using essentially the same software. Even the entry numbers were the same Here is the main page with the video.

https://www.youtube.com/channel/UCcMfCkN1juSa49DJFYltOTw

At about 16 minutes in, he talks about setting up the battery monitor. One part I did not even think about, you need to go to the F6.X entries first, and make sure those are correct for your shunt and voltage divider. He does a good job of explaining the float volts and amps settings. In their case, they are running 30S to the voltage is way up at 124.8 as he is setting it up.