What Causes Batteries to Not Even Charge to 50% Capacity?

[AgroVenturesPeru]

I've been dealing with some LiFePO4 battery problems for months now. The first twelve months following initial off-grid system installation everything was fine. Not a single problem. Then somewhere around the 12-13 month mark I noticed the battery bank would consistently top out at 88% according to the Touch50. Long story short, over the course of the past few months the battery bank would charge less and less. Every once in a while (seemingly randomly) the system would decide to charge the batteries up significantly higher than all other days. But still the downward trend continued.

Oh yeah, I didn't change anything prior to this problem starting.

Out of the bank of four batteries, one is now in the shop of the distributor being looked at. It was generating lots of low temperature alarms even when ambient temps were 80 degrees or 25C. The occasional internal failure alarm as well.

Well sent that unit in and down to three now, so reconfigured the capacity from 296ah down to 222ah using VEconfigure.
Then the next master battery generated an internal failure alarm.
We're operating with only three batteries now in a narrow band of about 20% to 40% charge and the recharge capacity still seems to be going down. They won't charge higher than about 40% now. It's not the solar or mppt, because when we run an appliance like an electric oven or water heater during the day, the MPPT will show going from an output of somewhere around 200w to 3000-4000w once the appliance is turned on.

Today I just decided to try running with only two batteries to see if that makes a difference. I know it's a long shot, but I want to see if maybe the bottom two batteries are free of errors. No one has any answers. At this rate it looks like we'll be in the dark in a couple months.

Here's some info about the batteries in case anyone's curious. They are the Pylontech US3000

Victron & Pylontech UP2500, US2000, US3000, US2000C, US3000C, US5000, US5000B, US5000C, Pelio-L, UP5000, Phantom-S, Force-L1 & L2 [Victron Energy]

www.victronenergy.com

 

[sunshine_eggo]

So are they controlling your GX?

Is each battery hitting 52V?

Have you tried disabling remote control and manually programming the absorption/float voltage?

Can you share your VRM?

 

[AgroVenturesPeru]

Mppt pretty much always displays the absorption light during the day. However, Daily History for the mppt on the Touch50 shows charge time being bulk 100% of the time (~12 hours).
At night the light for bulk flashes intermittently

 

[AgroVenturesPeru]

So are they controlling your GX?

Is each battery hitting 52V?

Have you tried disabling remote control and manually programming the absorption/float voltage?

Can you share your VRM?

"So are they controlling your GX?"
Who?What?

"Is each battery hitting 52V?"
I didn't pay particular attention to that, but I'm pretty sure that's a big fat NO. ~40% state of charge is not even 50V.

"Have you tried disabling remote control and manually programmingm the absorption/float voltage?"
That's doable on the VeConfigure software. And I think it's something I've tried before. What would you recommend the absorption and float be set to? I think it's currently set to 52 and 51 if I remember correctly. The other parameters I'm not even sure what they refer to when talking about hours and days. Are you familiar with VeConfigure software? I'm definitely a bigger fan of VeConfigure over VictronConnect.
On VeConfigure, I've thought about re-configuring the battery bank capacity and setting it as something extremely high like 888ah instead of the 148ah that two battery units would be, just to see if maybe the system will kick itself into high gear and start doing some proper charging if it thinks it still has a long way to go to a full charge. Then again, there may be some bad cells, which could cause the whole system to explode.

Do you think it's possible that all four batteries are garbage? They were all sold new/unopened from the factory.

"Can you share your VRM?"
Short answer, no.
Long answer: Can't remember how to even get VRM to display any of the information from my system. I logged on to my VRM the other day starting from the VictronConnect software, and my computer said the cerboGX was paired with my laptop's bluetooth, but the VRM website was not displaying any current information from my system at all. Is there an extra step I'm missing there?

 

[sunshine_eggo]

"So are they controlling your GX?"
Who?What?

I assume you have the BMS interfaced with the GX, and the BMS is in control of the system as a result.

"Is each battery hitting 52V?"
I didn't pay particular attention to that, but I'm pretty sure that's a big fat NO. ~40% state of charge is not even 50V.

Important to answer with a value vs. a guess.

"Have you tried disabling remote control and manually programmingm the absorption/float voltage?"
That's doable on the VeConfigure software. And I think it's something I've tried before. What would you recommend the absorption and float be set to? I think it's currently set to 52 and 51 if I remember correctly. The other parameters I'm not even sure what they refer to when talking about hours and days. Are you familiar with VeConfigure software? I'm definitely a bigger fan of VeConfigure over VictronConnect.

If you're charging with grid, yes, it's done in part in VEConfig as well as the GX Remote console.

On VeConfigure, I've thought about re-configuring the battery bank capacity and setting it as something extremely high like 888ah instead of the 148ah that two battery units would be, just to see if maybe the system will kick itself into high gear and start doing some proper charging if it thinks it still has a long way to go to a full charge.

This is not advised and will have no benefit.

Then again, there may be some bad cells, which could cause the whole system to explode.

Even so, the BMS should protect the cells.

Do you think it's possible that all four batteries are garbage? They were all sold new/unopened from the factory.

Anything is possible, but it's more probable that routine failure to charge to full has not permitted the BMS to balance the cells.

"Can you share your VRM?"
Short answer, no.
Long answer: Can't remember how to even get VRM to display any of the information from my system. I logged on to my VRM the other day starting from the VictronConnect software, and my computer said the cerboGX was paired with my laptop's bluetooth, but the VRM website was not displaying any current information from my system at all. Is there an extra step I'm missing there?

https://vrm.victronenergy.com/login to access VRM from a web browser.

There is also a VRM phone app.

Here's how you can share on VRM world:

VRM World [Victron Energy]

www.victronenergy.com

Do you have any assistants installed?

Can you access cell level voltage information?

 

[AgroVenturesPeru]

I assume you have the BMS interfaced with the GX, and the BMS is in control of the system as a result.

Couldn't say for sure. The BMS is internal and proprietary to each pylontech battery unit. I have a communication cable that was made by the distributor which connects the master battery's CAN port to the GX.

Important to answer with a value vs. a guess.

I looked today when it was at 40%. The voltage was 49.55.

If you're charging with grid, yes, it's done in part in VEConfig as well as the GX Remote console.

There is no grid here. Just PV power. MPPT 250/100. Multiplus 48/5000. Even still, it is possible to set the absorption and float votage to whatever one feels is appropriate using Veconfigure.

This is not advised and will have no benefit.

ok

Even so, the BMS should protect the cells.

ok

Anything is possible, but it's more probable that routine failure to charge to full has not permitted the BMS to balance the cells.

In that case, back to the original question: What would cause the batteries to progressively charge less and less over time?
Also, I don't see how that would explain the wacky alarm issues like low temperature alarm going off multiple times per day with temperatures in the upper 70s to 85 degrees fahrenheit, as well as the internal failure alarm that I've now seen on two of the four battery units. I think these are just shoddily built chinese batteries. I don't see why you would give them the benefit of the doubt at this point, unless you can brainstorm a few logical reasons why batteries would just decide to progressively charge less and less during their second year of use, while the first year they ran flawlessly. Nothing was reconfigured in the system, so I assume if the installation was the problem, we would've encountered some problems during the first 12 months.

https://vrm.victronenergy.com/login to access VRM from a web browser.

There is also a VRM phone app.

Here's how you can share on VRM world:

VRM World [Victron Energy]

www.victronenergy.com

Do you have any assistants installed?

I don't think so.

Can you access cell level voltage information?

No, I cannot. I was told by the distributor a few months ago, that if I purchased the necessary cable to run the batteryview software and view such information that they would no longer honor my warranty. Distributor has not been communicating well with us about the battery that they're supposedly testing in their shop. I will insist they comment regarding cell level voltage tomorrow. Their engineer just said, "we haven't gotten the error yet." Basically ignoring the main issue is the battery's inability to charge fully. If they really aren't going to do anything helpful with the battery we sent, then I will just go ahead and get that cable.

It looks like all four batteries have this same problem of not charging. We've had just two batteries installed for the past couple days. I paid attention today as they charged in the morning sun. Starting from 16% I watched as they charged moderately with currents of around ~25 amps, but then once they get into the upper 30 percentile, the current goes down and they charge in a range of 0.5-3 amps. Topped out again at 40% today. It is telling though, when the battery charge level shows 38 percent and charging @ 2 amps, and the wattage output of the MPPT shows about 200watts, and then the second you run an electric stove or water heater and the output on the mppt instantly climbs up to 1000-2000w +

 

[sunshine_eggo]

Couldn't say for sure. The BMS is internal and proprietary to each pylontech battery unit. I have a communication cable that was made by the distributor which connects the master battery's CAN port to the GX.

This suggests that you have the batteries in control of the system. They are providing information to the GX and dictating charging limits.

I looked today when it was at 40%. The voltage was 49.55.

Thank you.

There is no grid here. Just PV power. MPPT 250/100. Multiplus 48/5000. Even still, it is possible to set the absorption and float votage to whatever one feels is appropriate using Veconfigure.

VEconfig can set them, but the GX will override them because it's being controlled by the BMS.

One would need to first disable BMS control before charge voltages can be altered.

If you connect to the MPPT with VictronConnect, you will almost certainly see that it is under external control:

In that case, back to the original question: What would cause the batteries to progressively charge less and less over time?

All LFP batteries require to be regularly fully charged to allow the BMS to properly track the SoC AND balance any errant cells. Failure to fully charge repeatedly AND spend sufficient time at absorption voltage is a common cause of this.

BMS failure and cell failure are other possibilities.

Also, I don't see how that would explain the wacky alarm issues like low temperature alarm going off multiple times per day with temperatures in the upper 70s to 85 degrees fahrenheit,

That shoulds like a battery failure of some sort.

as well as the internal failure alarm that I've now seen on two of the four battery units.

This could be due to extreme imbalance that exceeds some limit.

I think these are just shoddily built chinese batteries.

They seem to be hit and miss. The cells are certainly not "EV Grade" but are generally accepted to meet capacity and perform acceptably. The brand is popular.

I don't see why you would give them the benefit of the doubt at this point, unless you can brainstorm a few logical reasons why batteries would just decide to progressively charge less and less during their second year of use, while the first year they ran flawlessly. Nothing was reconfigured in the system, so I assume if the installation was the problem, we would've encountered some problems during the first 12 months.

I am not giving the benefit of the doubt. I am troubleshooting.

I don't think so.

Given that you are off-grid it's not likely you have assistants installed. You can confirm this by connecting to the inverter with VEConfig and checking the Assistants tab.

No, I cannot. I was told by the distributor a few months ago, that if I purchased the necessary cable to run the batteryview software and view such information that they would no longer honor my warranty.

I'm speechless. They sound like total shitheads. The cable would get you to get additional data and empower you. They likely want you ignorant and helpless.

Does the warranty agreement forbid that in writing?

I would suggest that perhaps you could purchase the cable from another source and run the software to get additional information without making any changes.

Distributor has not been communicating well with us about the battery that they're supposedly testing in their shop. I will insist they comment regarding cell level voltage tomorrow. Their engineer just said, "we haven't gotten the error yet." Basically ignoring the main issue is the battery's inability to charge fully. If they really aren't going to do anything helpful with the battery we sent, then I will just go ahead and get that cable.

I recommend that you ask only two questions: 1) "have you fully charged the battery to 100% SoC?" If they say "no," then 2) "Why not?"

It looks like all four batteries have this same problem of not charging. We've had just two batteries installed for the past couple days. I paid attention today as they charged in the morning sun. Starting from 16% I watched as they charged moderately with currents of around ~25 amps, but then once they get into the upper 30 percentile, the current goes down and they charge in a range of 0.5-3 amps. Topped out again at 40% today. It is telling though, when the battery charge level shows 38 percent and charging @ 2 amps, and the wattage output of the MPPT shows about 200watts, and then the second you run an electric stove or water heater and the output on the mppt instantly climbs up to 1000-2000w +

The above describes the battery(ies) BMSs feeding a charge limit to the GX. The GX then restricts all attached devices to said limit (25A in your case). If loads require more, and it is available, the MPPT will output a higher limit.

From 3,000 miles away, it's essentially impossible to accurately diagnose what's going on, but here's what it sounds like to me:

1) Battery cells are imbalanced.
2) Due to imbalance, and one or more cells hitting upper voltage limit, BMS is telling the GX to restrict charging.
3) GX restricts charging.
4) Battery is unable to charge due to BMS imposed charge limit.

Why is this happening?

BMS failure
Battery failure
Excessive cell imbalance due to insufficient time at voltages/SoC that allow cell balancing.
Bad data cable(s)
Unknown error

I have three final questions:

Can you:
Change inverter settings via VEConfig?
Change MPPT settings via VictronConnect?
Change GX settings via Remote Console or a touch screen?

If the answer is "Yes" to all three, we can proceed with additional troubleshooting. If the answer to any of them is "no," then we're dead in the water.

Lastly, VRM is an indispensable tool in troubleshooting. Full VRM function and logging should be enabled.

So, basically, to continue, you are going to have to make an effort. If not, this is a waste of everybody's time.

 

[AgroVenturesPeru]

I have three final questions:

Can you:
Change inverter settings via VEConfig?
Change MPPT settings via VictronConnect?
Change GX settings via Remote Console or a touch screen?

If the answer is "Yes" to all three, we can proceed with additional troubleshooting. If the answer to any of them is "no," then we're dead in the water.

Lastly, VRM is an indispensable tool in troubleshooting. Full VRM function and logging should be enabled.

So, basically, to continue, you are going to have to make an effort. If not, this is a waste of everybody's time.

Okay first of all, thank you for the very long, well thought out response. You definitely sound like someone who knows their stuff.

I think the answer is Yes to all three questions, but I want to caveat by saying (just as you recognized) that even though I can change some parameters like the absorption and float voltages by connecting the inverter to VeConfigure - the BMS or whatever might override this. Another example is that under settings on the Touch50 DVCC is "Forced On."

 

[AgroVenturesPeru]

This suggests that you have the batteries in control of the system. They are providing information to the GX and dictating charging limits.



Thank you.



VEconfig can set them, but the GX will override them because it's being controlled by the BMS.

One would need to first disable BMS control before charge voltages can be altered.

If you connect to the MPPT with VictronConnect, you will almost certainly see that it is under external control:

View attachment 142154

I connected to the Smart Solar MPPT using victronconnect via bluetooth, and it shows "External control" under battery>State just like in your image.

 

[AgroVenturesPeru]

This suggests that you have the batteries in control of the system. They are providing information to the GX and dictating charging limits.



Thank you.



VEconfig can set them, but the GX will override them because it's being controlled by the BMS.

One would need to first disable BMS control before charge voltages can be altered.

If you connect to the MPPT with VictronConnect, you will almost certainly see that it is under external control:

View attachment 142154




All LFP batteries require to be regularly fully charged to allow the BMS to properly track the SoC AND balance any errant cells. Failure to fully charge repeatedly AND spend sufficient time at absorption voltage is a common cause of this.

BMS failure and cell failure are other possibilities.



That shoulds like a battery failure of some sort.



This could be due to extreme imbalance that exceeds some limit.



They seem to be hit and miss. The cells are certainly not "EV Grade" but are generally accepted to meet capacity and perform acceptably. The brand is popular.



I am not giving the benefit of the doubt. I am troubleshooting.

Okay those are insights I hadn't heard before. I text chatted via whatsapp with the distributor's electrical engineer last night and suggested to him to consider that it might be an issue with the BMS.

Given that you are off-grid it's not likely you have assistants installed. You can confirm this by connecting to the inverter with VEConfig and checking the Assistants tab.

No. There are no assistants installed.

I'm speechless. They sound like total shitheads. The cable would get you to get additional data and empower you. They likely want you ignorant and helpless.

Does the warranty agreement forbid that in writing?

I would suggest that perhaps you could purchase the cable from another source and run the software to get additional information without making any changes.

When I spoke to the distributor's EE last night he shared that they only used batteryview software with the same cable they had threatened me not to get months ago. I didn't need to send a battery unit to them just for that. I told him I thought they were going to remove the housing and manually test each cell, and he said they don't do that. Apparently, they are using a multiplus on the charge setting to recharge the battery with grid power AC.

The warranty does not forbid that, and the rep from Pylontech I spoke with months ago, even sent me the rar file to download batteryview software as well as some info about the connection cable needed. The manual does say that it needs to be a "Pylontech certified" technician to do the installation. So, hush hush about that.

After reading, the info Pylontech sent me about the batteryview cable, I bought two separate cables here from mercadolibre that connect in the middle to use, but alas they were not compatible. So, if I need to, I will buy something from an online distributor outside the country who sells the cables specifically for this purpose next time.

Here's the batteryview screenshot he sent me last night:


Looks just shy of 100% SoC. Though perhaps they took the screenshot before maybe getting to 100%
He did mention they discharged it to 10% which sounded a bit extreme to me. What do you think?

I recommend that you ask only two questions: 1) "have you fully charged the battery to 100% SoC?" If they say "no," then 2) "Why not?"

I asked, so we'll see what the answer is today. Edit: THIS JUST IN TODAY:

The above describes the battery(ies) BMSs feeding a charge limit to the GX. The GX then restricts all attached devices to said limit (25A in your case). If loads require more, and it is available, the MPPT will output a higher limit.

From 3,000 miles away, it's essentially impossible to accurately diagnose what's going on, but here's what it sounds like to me:

1) Battery cells are imbalanced.
2) Due to imbalance, and one or more cells hitting upper voltage limit, BMS is telling the GX to restrict charging.
3) GX restricts charging.
4) Battery is unable to charge due to BMS imposed charge limit.

Why is this happening?

BMS failure
Battery failure
Excessive cell imbalance due to insufficient time at voltages/SoC that allow cell balancing.
Bad data cable(s)
Unknown error

ok. I appreciate the insight.

The good news is that since we switched to only running the bottom two batteries in the stack, we haven't had any error messages or alarms. Bad news, is they have failed to charge above about 40%

 

[sunshine_eggo]

If they've had the unit on charge for an extended period, it may have resolved any cell imbalance.

Are you saying that you can't turn DVCC off? Some installers don't give all rights to the owner/user.

I'm guessing this value should be whatever the current is restricted to (25A, etc.), but I'm guessing:



Hopefully the battery cable will answer the questions. Cell imbalance issues really stand out with one or more cells at or above 3.65. On the Pylontech, they may be allowed to go as high as 3.9V.

Any success with getting VRM enabled and online?

 

[Horsefly]

I'm late to the game here, but... I thought I had heard that Pylontech LiFePO4 batteries used only 15 cells for their nominal 48V battery, which is one less than most of us would use. That would reduce the voltage across the entire charge / discharge curve. If the SoC estimate is using voltages that would apply to a 16 cell battery, that may translate to the battery never showing fully charged. Could that be part of the problem here?

 

[AgroVenturesPeru]

Will work on VRM after lunch today. What would you like to see on there?

Here's a quote:
"When DVCC is enabled, the battery (via the CAN-bms) is responsible for the charge voltage. The Pylontech battery requests a charge voltage of 53.2V. We have however found that in practice this is too high. The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell. This is very highly charged and makes the system prone to go overvoltage. It should also be noted that a LiFePO4 cell stores very little additional energy above 3.45V. For this reason we opted to override the BMS and cap the voltage at 52.4V. This sacrifices almost none of the capacity and greatly improves the stability of the system."
From this publication:

Victron & Pylontech UP2500, US2000, US3000, US2000C, US3000C, US5000, US5000B, US5000C, Pelio-L, UP5000, Phantom-S, Force-L1 & L2 [Victron Energy]

www.victronenergy.com

On my system (for whatever reason)
DVCC is forced on
SVS - Forced Off
STS -Forced Off
The Touch50 only shows Limit charge current, limit managed battery charge voltage, and SCS as able to modify.
SCS status, however, is "Disabled (External control)"

This just in: The distributor got the error messages: Low temp, internal failure, and another I hadn't seen before: something about low voltage.

 

[sunshine_eggo]

I'm late to the game here, but... I thought I had heard that Pylontech LiFePO4 batteries used only 15 cells for their nominal 48V battery, which is one less than most of us would use. That would reduce the voltage across the entire charge / discharge curve. If the SoC estimate is using voltages that would apply to a 16 cell battery, that may translate to the battery never showing fully charged. Could that be part of the problem here?

It doesn't. Victron communication with this type of battery was first developed for the Pylontech. The protocol has actually been problematic in trying to adapt it to the 16S SOK and EG4 server rack batteries due to something hard coded for 15S vs. 16S. IIRC, this has been corrected.

Will work on VRM after lunch today. What would you like to see on there?

The BMS should appear as a "battery monitor" device. Enable all widgets from that battery monitor.

Here's a quote:
"When DVCC is enabled, the battery (via the CAN-bms) is responsible for the charge voltage. The Pylontech battery requests a charge voltage of 53.2V. We have however found that in practice this is too high. The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell. This is very highly charged and makes the system prone to go overvoltage. It should also be noted that a LiFePO4 cell stores very little additional energy above 3.45V. For this reason we opted to override the BMS and cap the voltage at 52.4V. This sacrifices almost none of the capacity and greatly improves the stability of the system."
From this publication:

Victron & Pylontech UP2500, US2000, US3000, US2000C, US3000C, US5000, US5000B, US5000C, Pelio-L, UP5000, Phantom-S, Force-L1 & L2 [Victron Energy]

www.victronenergy.com

52.4V should be good, but it seems you're never getting there.

On my system (for whatever reason)
DVCC is forced on
SVS - Forced Off
STS -Forced Off
The Touch50 only shows Limit charge current, limit managed battery charge voltage, and SCS as able to modify.
SCS status, however, is "Disabled (External control)"

Correct. DVCC is what gives the BMS control over the GX, so my comments about disabling it are no longer value since you can't turn it off.

This just in: The distributor got the error messages: Low temp, internal failure, and another I hadn't seen before: something about low voltage.


View attachment 142241

That's good news. Hopefully, it's under warranty, and they'll replace it. It may also make them more receptive to your concerns about the batteries refusing to charge to 100%.

 

[AgroVenturesPeru]

Is each battery hitting 52V?

If you mean is the battery itself holding a voltage of 52v, right? If that is the question, then the answer is No, it is not. See my earlier comment telling you the voltage of the battery bank when it was at 40% SoC.

If however, you are asking if they Mppt is charging the batteries with 52V, then the answer is that right now as I'm typing the MPPT is charging the batteries with 52.4V (according to the status tab for my mppt on victronconnect).

Have you tried disabling remote control and manually programming the absorption/float voltage?

How can I do that?

 

[sunshine_eggo]

If you mean is the battery itself holding a voltage of 52v, right? If that is the question, then the answer is No, it is not. See my earlier comment telling you the voltage of the battery bank when it was at 40% SoC.

Yep. Just making sure. We need to look at SoC as a secondary value. Right now, what matters is voltage.

If however, you are asking if they Mppt is charging the batteries with 52V, then the answer is that right now as I'm typing the MPPT is charging the batteries with 52.4V (according to the status tab for my mppt on victronconnect).

So the charge controller is showing 52.4V output to the battery?
What does the battery(ies) report for voltage?
can you confirm the voltage by measuring with a voltmeter at a battery terminal?

VRM would provide a historical record of these data.

How can I do that?

You can't - because DVCC is forced on. You have to turn DVCC off to do this.

 

[AgroVenturesPeru]

The BMS should appear as a "battery monitor" device. Enable all widgets from that battery monitor.

Still working on getting connected. We have gotten on our VRM portal, but it's all info from 7 months ago, and I haven't figured out how to display the current info. It seems there's a problem with connecting to the CerboGX via bluetooth. Maybe the Cerbo needs a firmware update first. Do you happen to know the link to download its firmware updates?
I remember last time we did it we had to install via a usb flash drive.

Correct. DVCC is what gives the BMS control over the GX, so my comments about disabling it are no longer value since you can't turn it off.

Are you sure there's no way to turn off DVCC? Or at least override it another way?

That's good news. Hopefully, it's under warranty, and they'll replace it. It may also make them more receptive to your concerns about the batteries refusing to charge to 100%.

What I don't understand is how they were able to get the battery to charge to 100% SoC whereas I'm stuck with less than 40% SoC with the batteries here?

Also seems odd that all four of my batteries have this problem. Kind of makes me not want replacement Pylontech batteries. Besides, what are we supposed to do until then? Sit in the dark?

 

[AgroVenturesPeru]

Yep. Just making sure. We need to look at SoC as a secondary value. Right now, what matters is voltage.



So the charge controller is showing 52.4V output to the battery?
What does the battery(ies) report for voltage?
can you confirm the voltage by measuring with a voltmeter at a battery terminal?

VRM would provide a historical record of these data.



You can't - because DVCC is forced on. You have to turn DVCC off to do this.

The battery reports 49.6v while the mppt is sending 52.4V to it. LOoks like we're topped out at 35% today. By the way, I flipped the master/slave order of the two batteries a couple hours ago. Doesn't look like it matters which of the two is the master - either way they're not charging properly. Still no alarms though...knock on wood.

Note, I did not take the above reading with a voltmeter. It is just what the cerboGX is showing. I suppose I could take multimeter reading, but my multimeter is in storage right now, and it's not something I'm eager to do. First things first, just trying to catch up with the other stuff you told me already (namely getting my VRM to show the actualized info).

Regarding the DVCC being forced on, I assume even if I knew how to override that, it would most likely invalidate the warranty.

 

[sunshine_eggo]

Still working on getting connected. We have gotten on our VRM portal, but it's all info from 7 months ago, and I haven't figured out how to display the current info. It seems there's a problem with connecting to the CerboGX via bluetooth. Maybe the Cerbo needs a firmware update first. Do you happen to know the link to download its firmware updates?

I don't have a Cerbo. I have a CCGX, but they are fundamentally very similar. If they are internet connected, they can download the firmware. There is a firmware update option somwhere in the menus.

I would not update the Cerbo firmware unless it is very old.

I remember last time we did it we had to install via a usb flash drive.

This implies the Cerbo is not Internet connected.

Are you sure there's no way to turn off DVCC? Or at least override it another way?

If you can't turn off DVCC, then your only option is to remove the GX from the system, i.e., disconnect the BMS, MPPT and MP from the Cerbo, and reboot the MPPT and MP.

What I don't understand is how they were able to get the battery to charge to 100% SoC whereas I'm stuck with less than 40% SoC with the batteries here?

You said yourself they were charging via grid. This allows them to apply a continuous charge and permit the BMS to balance the cells. As the high cells are bled down, the low cells are able to take on additional charge. Eventually, all cells can achieve full charge.

Also seems odd that all four of my batteries have this problem. Kind of makes me not want replacement Pylontech batteries.

I wouldn't be surprised if there's a batch problem. If you order four of something, there's a good chance they were made at or near the same time from a group of cells that were made at or near the same time. All it takes is one or more cells in a battery to have slightly higher self-discharge than the others. Couple that with potentially inconsistent charging and insufficient time at 100% SoC to enable balancing, and it's just a matter of time until a problem surfaces.

Besides, what are we supposed to do until then? Sit in the dark?

I would hope that you have a backup power source like a generator.

 

[sunshine_eggo]

The battery reports 49.6v while the mppt is sending 52.4V to it.

That is highly irregular. In a DVCC enabled system, the MPPT should be getting voltage data from the BMS... though you did indicate SVS (shared voltage source) is forced off. not sure if that matters in your case, but that's still odd.

LOoks like we're topped out at 35% today. By the way, I flipped the master/slave order of the two batteries a couple hours ago. Doesn't look like it matters which of the two is the master - either way they're not charging properly. Still no alarms though...knock on wood.

Okay.

Note, I did not take the above reading with a voltmeter. It is just what the cerboGX is showing. I suppose I could take multimeter reading, but my multimeter is in storage right now, and it's not something I'm eager to do.

I just don't understand this. A multimeter is a fundamental piece of hardware that should be stored within 10 feet (or other ready access) of your system. It is too useful of a diagnostic tool to be in storage.

A ~3V difference between the MPPT and battery voltage may be indicative of a problem. You need to measure and compare:

1) voltage at battery terminals on battery.
2) Voltage reported by battery.
3) Current reported by battery.
4) Voltage at battery terminals on the MPPT.
5) Voltage reported by the MPPT.
6) Current reported by the MPPT.

The values should be recorded as quickly as possible with constant amps into the battery.

There will likely be a difference since the multimeter and components have different accuracy and calibrations. That's why it's important to get all values for comparison.

First things first, just trying to catch up with the other stuff you told me already (namely getting my VRM to show the actualized info).

The Cerbo should automatically upload data when it is internet connected. It should also have a MicroSD card that can record days/months of data for later upload.

Regarding the DVCC being forced on, I assume even if I knew how to override that, it would most likely invalidate the warranty.

I would take the position that if it isn't prohibited in writing, there is no justification for invalidating the warranty.