Schneider Conext SW 4024 charger setting

[dustonlarsen]

I have a conext sw 4024 inverter/charger with a midnight classic off grid. I have 4 6v agm batteries for 24v and 260 amp hours. When I use the generator, rarely, the sw4024 will start in bulk but immediately go to abosorb after it’s allotted 3 minutes of being at bulk max voltage, 28.4v. I am trying to figure out why once I am charging the batteries the SW4024 is reading the batteries at full voltage and switching to absorb. Absorb seems to work fine and kicks off when appropriate. @GXMnow maybe you have insight? I did call Schneider and they said my batteries were bad but that just didn’t make sense to me. Below are pics of charge settings:

Before generator is manual turned on

Once generator kicks on

3 minutes later switches to absorb


Settings

 

[sunshine_eggo]

If this is happening when you're battery is essentially full or near full, this is normal.

If that's not the case, there's a malfunction, or you have excessive voltage drop between the inverter and battery.

Use a voltmeter and measure DC voltage AT the battery terminals and AT the inverter terminals. This can occur during charge or discharge, and it's best if you can do it with a constant current. Take a few measurements and find the average voltage drop.

If you measure a voltage drop, carefully check that all connections between the battery and inverter are properly torqued.

Lastly, breakers and fuses can produce far more resistance than they should if they are in the process of failing.

 

[GXMnow]

It looks to me like you are charging at too much current, and/or you have too much resistance somewhere in the battery circuit.

Typical AGM batteries should be charged at a 0.1C rate. For a 260 amp hour bank, that would be just 26 amps. 100% charge rate on the SW-4024 is 90 amps. That is way to much. That is pulling the voltage up and triggering the end of bulk charging. Try setting the maximum charge rate down to just 29% which should be close to 26 amps, and see how it goes. That works out to about 750 watts of charging power. If the battery bank was drained down to 50% charge, it will take 5 hours to charge it back up to full. In your pictures, the battery current never even got up to 20 amps, so it does look like you have a resistance issue. Like sunshine-eggo said, check the voltage drop and all the connections.

Are you running a state of charge meter? It also looks like your batteries are close to full. Yes, resting at 25.2 volts is close to full. 100% state of charge, after the battery has ben sitting at no load or charge current, should be about 25.7 volts. Your 25.2 volts is about 80% charged. It sounds like the SW is doing what it can to not boil all the acid out of your cells.

 

[dustonlarsen]

It looks to me like you are charging at too much current, and/or you have too much resistance somewhere in the battery circuit.

Typical AGM batteries should be charged at a 0.1C rate. For a 260 amp hour bank, that would be just 26 amps. 100% charge rate on the SW-4024 is 90 amps. That is way to much. That is pulling the voltage up and triggering the end of bulk charging. Try setting the maximum charge rate down to just 29% which should be close to 26 amps, and see how it goes. That works out to about 750 watts of charging power. If the battery bank was drained down to 50% charge, it will take 5 hours to charge it back up to full. In your pictures, the battery current never even got up to 20 amps, so it does look like you have a resistance issue. Like sunshine-eggo said, check the voltage drop and all the connections.

Are you running a state of charge meter? It also looks like your batteries are close to full. Yes, resting at 25.2 volts is close to full. 100% state of charge, after the battery has ben sitting at no load or charge current, should be about 25.7 volts. Your 25.2 volts is about 80% charged. It sounds like the SW is doing what it can to not boil all the acid out of your cells.

I’ll check that stuff. The odd thing for me is when it’s charging through the midnite CC from PV panels it works perfect, bulk-absorb-float, or what seems normal to me. I have a wizbang jr for my SOC meter on the Classic. It’s a new system just over 1 year old.

When I am active charging from Midnite/pv panels and I take meter readings from the batteries I will get actual volt readings and watch them rise with the charge until it gets to 28.4. With the generator on, no pv charge, meter readings from the batteries show 28.4 no matter then once the generator is off they will drop to whatever volt they were at or charge to. The generator I have can only put out around 20amps, it’s just a temp to get by while installing a permanent propane one.

I did slightly kill my batteries last winter. I lost the top 10 or 20 percent. I left power on and they never fully charged for over a month when I wasn’t there. They will float at 27v but the second a charge is off they drop to 25.3. Not a big deal. My friend said, don’t buy expensive batteries at first. Trust me you’ll f’em up. I sure did. Just more info.

 

[dustonlarsen]

Minor update. I did just check the volt drop and that was fine. It was an all pre wired kit and same length battery cables. Everything is tight. When I was charging I set the charge rate down and that didn’t change anything. I did though notice while gen was on my third battery in line was reading 7.18-7.2 volts while the other 3 were reading 7.03-7.04. That’s probably what’s causing it to go from bulk to absorb? I still don’t comprehend why the batteries read full voltage when charging though. I would assume they would show the actual voltage like when they are being charged from the PV array. This is all still foreign to me even though I’ve been running it for a year.

 

[sunshine_eggo]

I did slightly kill my batteries last winter. I lost the top 10 or 20 percent. I left power on and they never fully charged for over a month when I wasn’t there. They will float at 27v but the second a charge is off they drop to 25.3. Not a big deal. My friend said, don’t buy expensive batteries at first. Trust me you’ll f’em up. I sure did. Just more info.

This is probably the most important information you've posted on this matter and gives insight into why Schneider says your batteries are bad. Initially, it was easy to dismiss it as mediocre customer support wanting to get rid of you, but this confession casts it all in a new light.

On the surface, the situation doesn't sound like a death sentence, but unless we can understand what really happened, it's hard to say. If they drop to 25.3 with no load on them after an extended float at 27V, you just plain need new batteries, and the behavior you're observing is consistent with trashed batteries.

 

[sunshine_eggo]

Minor update. I did just check the volt drop and that was fine. It was an all pre wired kit and same length battery cables. Everything is tight. When I was charging I set the charge rate down and that didn’t change anything. I did though notice while gen was on my third battery in line was reading 7.18-7.2 volts while the other 3 were reading 7.03-7.04. That’s probably what’s causing it to go from bulk to absorb? I still don’t comprehend why the batteries read full voltage when charging though. I would assume they would show the actual voltage like when they are being charged from the PV array. This is all still foreign to me even though I’ve been running it for a year.

That's a pretty horrific disparity in voltages. They should all be very nearly the same. The 7.2 is likely being over charged, and the 7.0X are likely being under-charged. Consistent operation in this manner ensures rapid battery deterioration.

The best course of action would be to charge each 6V battery individually or in parallel to full and then reconfigure in series.

 

[dustonlarsen]

This is probably the most important information you've posted on this matter and gives insight into why Schneider says your batteries are bad. Initially, it was easy to dismiss it as mediocre customer support wanting to get rid of you, but this confession casts it all in a new light.

On the surface, the situation doesn't sound like a death sentence, but unless we can understand what really happened, it's hard to say. If they drop to 25.3 with no load on them after an extended float at 27V, you just plain need new batteries, and the behavior you're observing is consistent with trashed batteries.

? agree. my cells are somewhere in a boat. I got caught up in the group buy debacle but it all worked out in the end. Now waiting on eve cells from shenzen luyan.

 

[dustonlarsen]

That's a pretty horrific disparity in voltages. They should all be very nearly the same. The 7.2 is likely being over charged, and the 7.0X are likely being under-charged. Consistent operation in this manner ensures rapid battery deterioration.

The best course of action would be to charge each 6V battery individually or in parallel to full and then reconfigure in series.

It’s only when the gen charge is applied which is strange. I’ll check again tomorrow when the suns out but PV charging I have seen them slip a little but not that much. Plus or minus .02. once the charge is removed they all equal out. Not saying I am ok with the 7.2 just readings I say. Right now they are 6.20-6.18-6.18-6.20. Thanks for all your insight. Appreciate it.

 

[sunshine_eggo]

My guess is the period of excessive discharge essentially bottomed out those batteries, and they've never been in "synch". Since they can't be equalized in series safely (AGM), they've just never recovered. You might see some improvement if you get each of them to 100% as I described.

Additionally, consider increasing your float to 27.6V. This is a safe float voltage for AGM, and the lower batteries can take on additional charge while posing less risk of damage to the highest battery.

 

[Skip]

This thread has been helpful. I'm having a similar issue. System is a conext SW 4024, four 12v Kilovault AGM batteries - 2 series in parallel for 24v. Total 360 Ah. Midnite Classic 150 with 6 Q cells- total of about 2500 watts solar at 48v.
New system installed June of this year.
Everything was great until the short cloudy days set it. I did my best from the manuals to set the conext charger to all the right settings. Fired up the generator and had 29 volts at the SCP readout. That didn't seem right. Checked the voltage at the conext battery terminals and at the batteries themselves - both locations at about 28 volts (analog volt meter).
Using a 4.5Kw running watt generator.
After two weeks, four different tech support with two different companies, I finally got my hands on the Kilovault/Context Integration Guide. Corrected a few settings and things got a lot better.
What does not seem right is that despite the level of solar during the day, I'm down to 50% DOD on the batteries by 8 pm (sunset here around 5 pm). This is with less that 400 watts of load, typically. A 10 cu ft refrigerator set to warm, laptop, computer speakers and a few LED lights.
During my several weeks of trial and error getting the AC charging figured out, I had maybe 3 or 4 two hour charge sessions where the readout said 29 volts. Not wanting to do more, I had one morning where the batteries went to 40% and another where they went to 30%. Solar charging brought them back each day, I've been running periodic equalization sessions of 90 minutes each on solar, particularly after those low DOD nights.
Based on the advice above, I set my rate of charge on the conext to 29% and ran a 2.5 hour charge session this morning (heavy cloud cover) until the solar was able to take over, so the batteries got a fair amount (but not great) of Bulk and Absorption today. I get about 30 minutes of Bulk and the Absorption. Still down to 50% by 8 pm with minimal load. This doesn't seem right.
I checked the voltage at each battery as suggested above and I have the same reading at each battery: 13v during Absorption stage on AC (again, not precise due to analog meter).
Is there something different I can do to rebuild the batteries? Is it possible they will heal over time with proper charging from here on out?

One more note - I installed a Primus Air 40 wind turbine a month ago and it charges at Bulk rate when there is wind until the batteries reach max charge of 28.2v. On those nights when there is sufficient wind it can keep the batteries up in the 60% to 80% range.

Thanks

There is no such thing as a free education.

 

[Skip]

One thing I've noted in the Kilovault documentation is that they want the Bulk rate set to 24.4v (12.2*2) for 50% DOD. The conext charger does not have a variable for that - only the Classic.

PLC Manual Corrections

Greetings,There are some typos in the PLC 2100 manual that need to be corrected. Page 9 Float Voltage - 13.6V Bulk Voltage - 14.1V Recharge/Rebulk for a …

kilovault.com

Since my AC charge is set to start at 50% discharge, I'll set the bulk rate to 24.4v and see if that helps.
I think I've been overcharging on AC for the past 2 months.
The conext/Kilovault integration guide specifies 24.6v for recharge volts. But, when you carefully study the conext user manual, they have a different definition for recharge. In the conext, recharge voltage"sets the recharging volts to tell the charger to initiate charging when the battery drains past the value setting." In the Kilovault documentation, Recharge/Rebulk is the charge voltage for charging from a 50% DOD. They are not speaking the same language. If I follow the conext or the integration guide settings, the batteries are always going to get too much bulk charge if I only start AC charging at 50% DOD.

 

[sunshine_eggo]

What does not seem right is that despite the level of solar during the day, I'm down to 50% DOD on the batteries by 8 pm (sunset here around 5 pm). This is with less that 400 watts of load, typically. A 10 cu ft refrigerator set to warm, laptop, computer speakers and a few LED lights.

I didn't see it if you mentioned it, what is reporting 50% SoC?

During my several weeks of trial and error getting the AC charging figured out, I had maybe 3 or 4 two hour charge sessions where the readout said 29 volts.

Assuming I looked up the right battery, they recommend 28.2V bulk.

Not wanting to do more, I had one morning where the batteries went to 40% and another where they went to 30%. Solar charging brought them back each day,

Did you check voltage and confirm? Did you check each of the 12V elements to see if they had a significant disparity?

I've been running periodic equalization sessions of 90 minutes each on solar, particularly after those low DOD nights.

Equalization of AGM should generally be avoided unless it's just a slight elevation above typical bulk.

Based on the advice above, I set my rate of charge on the conext to 29% and ran a 2.5 hour charge session this morning (heavy cloud cover) until the solar was able to take over, so the batteries got a fair amount (but not great) of Bulk and Absorption today. I get about 30 minutes of Bulk and the Absorption. Still down to 50% by 8 pm with minimal load. This doesn't seem right.

Have you confirmed all voltage/current readings with different tools?

I checked the voltage at each battery as suggested above and I have the same reading at each battery: 13v during Absorption stage on AC (again, not precise due to analog meter).

13V absorption is way too low. Absorption should be 14.1V; float 13.7V.

Is there something different I can do to rebuild the batteries? Is it possible they will heal over time with proper charging from here on out?

They won't "heal" but their performance might improve if you're charging them properly. If you've abused them, or you've consistently under-charged/over-discharged, then they won't get any better.

One more note - I installed a Primus Air 40 wind turbine a month ago and it charges at Bulk rate when there is wind until the batteries reach max charge of 28.2v. On those nights when there is sufficient wind it can keep the batteries up in the 60% to 80% range.

What does the turbine do when it hits absorption? Is there a dump load?

 

[Skip]

50% DOD for my battery bank is 24.6 volts
Yes. Bulk charge for the Kilovault is 28.2v, EXCEPT following 50% discharge, in which case they specify 24.4v
When I'm on AC charge, the absorption phase only runs for about 90 minutes and then switches to float. Absorption voltage is set to 28.2v.
That 13v reading was at the beginning of the Absorption cycle.
Interesting that on the SCP, during AC charging, the meters screen reads out 28.2v, but on the status screen, the BatLev E--F bar graphically represents the true battery level.
I initially suspected inaccurate readings with my volt meter, but checked them with a borrowed digital volt meter and confirmed they give the same readings. A new digital meter is on my shopping list.

The conext charger isn't giving any more than about 90 minutes of Absorb. I have it set to 480 minutes. My AC house load reads out at less than 1 amp.

The wind turbine has an internal charge controller and only charges Bulk. There is no dump load. It simply applies the electromagnetic brake when batteries reach full charge of 28.2v. Not happy with the Primus turbine. Power output is much lower than advertised and the brake failed in a 54 mph wind gust and it burned itself up. I am thinking that a Hurricane Wind Power turbine with another Classic 150 is in my future.
As Dustin noted in his setup above, I get proper charging with solar through the classic, but the conext charger does not seem to handle charging correctly.

I'm suspecting that the batteries are simply not getting enough charge everyday. Kilovault wants an 8 hour AC charge session - that's just simply too much generator time everyday. Even though they appear to come up to full charge, as soon as the charging is removed, either AC or solar, they quickly drop to 80% and then more gradually drop to 50% where they seem to hold pretty well.

I was concerned about regular undercharging, but then came across some Kilovault marketing info: "Partial State of Charge Applications - Pure Lead + carbon = greater life cycle in both PSoC and non PSoC off-grid operations. In PSoC/daily cycling applications, the batteries do not need to be fully charged every day, and they will still get 3000 cycles." Given that, I guess the proof will be how they perform in another 4 months when we get back to 12 hours a day of full sunlight.

On the Equalization, Kilovault states that equalization should be rarely used, EXCEPT following discharge of more than 80% - well, that's pretty much every day. I feel like they could offer some more education on that point.

Ran a 2.5 hour generator AC charge session last night. 30 minutes Bulk, 90 minutes Aborb and remainder float. Turned off the refrigerator, so the only thing running all night was my CPAP machine, which draws minimal load. Batteries at about 25v when I went to bed, but at 24.7v this morning.
Sounds like they may be just toast and all need to be replaced, unless it's just a chronic undercharge situation. Not enough sunlight this time of year and I haven't been able to bring myself to run the generator for 8 hours a day. Maybe I'll try some 4 hour sessions when I get the new propane fueled generator installed.

I feel like I have learned just about everything there is to know about these batteries and the conext charger. Where I'm really lacking is understanding what has been going on for the last 5 and a half months and the long term affect that history has had on the batteries. For most of that time, Midnite Solar seems to have done a fine job of managing the batteries. The conext charger, not so much.

 

[Skip]

Here is the Kilovault documentation source: https://kilovault.com/kilovault-plc-2100/

https://kilovault.com/wp-content/uploads/2021/10/KiloVault-2100-PLC-Installation-and-User-Manual-Rev-1.05-a.pdf

In this manual, on page 16, the graph shows that each individual cell has a 50% state of charge of about 2.05v. Each battery has six cells, so each battery 50% level should be 12.3v * 2 = 24.6 for a 24v system - this is what tech support is telling me.
Read the overview on page 9 of the installation guide - these Kilovaults are a little different from run of the mill AGM's. That's why the conext has be be custom programmed for them.

Here is the Integration Guide to configure the Conext SW charger for these particular batteries: https://kilovault.com/wp-content/up...-4048_KiloVault_Integration_Guide_May2021.pdf

I'm not seeing any disparity between the two sets of batteries, or between the individual batteries, but I have considered charging the two pairs individually.

These are still under warranty. Purchased from AltEstore.com. Interestingly, the street address for Altestore and Kilovault is the same. So, I surmise that altestore has designed and manufactured these batteries under a division of their own organization.

I'm begging to see that these are so unique that I'm going to have to rely on the manufacturer to enlighten me about what is normal v. abnormal behavior for the batteries.

 

[sunshine_eggo]

My apologies... I thought I was responding to a different thread. I have deleted my post.

 

[dustonlarsen]

Just to close this out. It was my charge rate setting. This is the tricky part with these inverter/chargers. The default battery setting does not seem to work in most cases. Either the temperature compensation is wrong or the charge rate. In my situation, which my batteries are just renogy agm’s, I have to use custom battery settings. I more than likely damaged the batteries the first time a year ago I kicked on the generator with the charge rate set at default, ? or 90 amps.

Thanks @GXMnow thx for your help and was the solution. I had my charge rate at 17%, which was 15 amps(90x17%) and the voltage was still creeping too up quickly. I dropped it to 10% and it’s looking to charge correctly. I can probably bump it up to 11or 12 but I am going to see how this goes first.

Lesson learned set your charge rate at 10% and move up from there and glad I bought shitty batteries while I was learning. Charge rate, amps into the battery, is extremely important to know. The conext is not intuitive for a no vice like me. The Midnite charge controller is, and the settings are set so low on everything that you usually won’t damage anything if you miss a setting. That was my assumption. That the conext would have low settings like the Midnite.

@Skip and @sunshine_eggo thanks for your comments/questions as well

 

[dustonlarsen]

And just to clarify for future views, my generator could only push max 30 amps into the batteries so it had that surge which pushed the voltage to 28.4, triggered the conext 4024 charger to go to absorb and then throttled the amps down to 18-23. I think if it could have put 90amps into those batteries I could have potentially had a larger problem.

 

[JDFEARL]

This thread has been helpful. I'm having a similar issue. System is a conext SW 4024, four 12v Kilovault AGM batteries - 2 series in parallel for 24v. Total 360 Ah. Midnite Classic 150 with 6 Q cells- total of about 2500 watts solar at 48v.
New system installed June of this year.
Everything was great until the short cloudy days set it. I did my best from the manuals to set the conext charger to all the right settings. Fired up the generator and had 29 volts at the SCP readout. That didn't seem right. Checked the voltage at the conext battery terminals and at the batteries themselves - both locations at about 28 volts (analog volt meter).
Using a 4.5Kw running watt generator.
After two weeks, four different tech support with two different companies, I finally got my hands on the Kilovault/Context Integration Guide. Corrected a few settings and things got a lot better.
What does not seem right is that despite the level of solar during the day, I'm down to 50% DOD on the batteries by 8 pm (sunset here around 5 pm). This is with less that 400 watts of load, typically. A 10 cu ft refrigerator set to warm, laptop, computer speakers and a few LED lights.
During my several weeks of trial and error getting the AC charging figured out, I had maybe 3 or 4 two hour charge sessions where the readout said 29 volts. Not wanting to do more, I had one morning where the batteries went to 40% and another where they went to 30%. Solar charging brought them back each day, I've been running periodic equalization sessions of 90 minutes each on solar, particularly after those low DOD nights.
Based on the advice above, I set my rate of charge on the conext to 29% and ran a 2.5 hour charge session this morning (heavy cloud cover) until the solar was able to take over, so the batteries got a fair amount (but not great) of Bulk and Absorption today. I get about 30 minutes of Bulk and the Absorption. Still down to 50% by 8 pm with minimal load. This doesn't seem right.
I checked the voltage at each battery as suggested above and I have the same reading at each battery: 13v during Absorption stage on AC (again, not precise due to analog meter).
Is there something different I can do to rebuild the batteries? Is it possible they will heal over time with proper charging from here on out?

One more note - I installed a Primus Air 40 wind turbine a month ago and it charges at Bulk rate when there is wind until the batteries reach max charge of 28.2v. On those nights when there is sufficient wind it can keep the batteries up in the 60% to 80% range.

Thanks

There is no such thing as a free education.

did you connect the Primus to the batteries/separate charge controller/something else? Just curious, looking to do the same

 

[Skip]

The Primus turbines have an internal charge controller, so they hook up to the battery. You do need a stop switch, breaker and ammeter in line between the turbine and batteries. The turbines will apply the electromagnetic break under two conditions: when the batteries reach full charge (to protect the batteries) and when sustained winds exceed 35 mph (to protect the turbine from overheating).
Having said that, with what I've learned since, I'm not sure I would have gone this route. I think my next turbine will be an AC unit with rectifier, excess power dump(s) and another Classic 150. I think I could get a LOT more power this way and have more control as well.