Been following this with interest, so, are you leaving it at 53.2v

What is the expectation? Is there any guidance from the manufacturers as to what should happen when the batteries are fully charged? Are you sure this is an actual problem? 

1 hour ago, DeepBass9 said:

What is the expectation? Is there any guidance from the manufacturers as to what should happen when the batteries are fully charged? Are you sure this is an actual problem? 

It was @SolarNoob who said this is jot balanced. I didn't see it as a problem. I'm just data gathering to see how the battery behaves in different conditions.

I would be inclined to use a lower charge voltage on the basis that Victron did so, and because avoiding extremes od charge and discharge is good for cell life. 

 

Hi Elbow,

if I get it correctly, the original problem is:

1) When fully charged and kept in float, one of your Pylons will throw and error and will disconnect itself.
2) You see that as the battery is being charged to the top, there's a visible difference in the voltage between the lowest and highest cell.

Am I Right?
Question: Did the Pylon throw an error and disconnect itself during a discharging phase too? I assume that the answer is NO.

 

Well, I experienced a similar issue with other brand's intelligent battery in the past and the root cause was that I was basically overcharging it. When applied to Pylon US2000B Plus:

- Pylon is 15x LFP in series.
- When you charge over 3.48V per cell, then the balancers will start to act.
- These balancers are meant to level the voltage of all the cells when fully charged. They are doing this, but cannot keep-up for a long time, especially if the charger is still pushing the current into the battery.

Given we can use 2 charging states, CC + CV, it makes sense to set charging like this:
CC = 15x 3.55V = 53.2V
CV = 15x 3.48V= 52.2V

For the CC phase, it's pretty safe to set even higher voltage, up to 54V for Pylon (3.6V per cell).
But the CV phase is critical and you shouldn't hold the batteries on the higher voltage for too long.

With the above settings, you should be able to get to 100% SoC, where you will start to notice a difference in voltage of the individual cells. Then, the balancers will kick-in and once the charger will go into the CV stage, you should see that all the cells are on the same voltage of 3.48V. Also, there should not be an error, nor battery self-disconnect issue.

My 2cents.

Just a note, for my 16S LFP packs I'm using CC=56V (3.5V per cell), CV = 55.6V (3.475V per cell).
But I had the luxury of seeing the LED on each balancer, so I knew whether balancers were fully engaged for a long time, or whether they were just acting here and there (as designed).

Edited March 3, 20197 yr by Youda

Just now, Youda said:

 

1) When fully charged and kept in float, one of your Pylons will throw and error and will disconnect itself.
2) You see that as the battery is being charged to the top, there's a visible difference in the voltage between the lowest and highest cell.

Am I Right?
Question: Did the Pylon throw an error and disconnect itself during a discharging phase too? I assume that the answer is NO.

 

Well, I experienced a similar issue with other brand's intelligent battery in the past and the root cause was that I was basically overcharging it. When applied to Pylon US2000B Plus:

- Pylon is 15x LFP in series.
- When you charge over 3.48V per cell, then the balancers will start to act.
- These balancers are meant to level the voltage of all the cells when fully charged. They are doing this, but cannot keep-up for a long time, especially if the charger is still pushing the current into the battery.

Given we can use 2 charging states, CC + CV, it makes sense to set charging like this:
CC = 15x 3.55V = 53.2V
CV = 15x 3.48V= 52.2V

For the CC phase, it's pretty safe to set even higher voltage, up to 54V for Pylon (3.6V per cell).
But the CV phase is critical and you shouldn't hold the batteries on the higher voltage for too long.

With the above settings, you should be able to get to 100% SoC, where you will start to notice a difference in voltage of the individual cells. Then, the balancers will kick-in and once the charger will go into the CV stage, you should see that all the cells are on the same voltage of 3.48V. Also, there should not be an error, nor battery self-disconnect issue.

My 2cents.

 

Hi @Youda,

Yes, I didn’t have any alarms before I was leaving the batteries on 52v float.  But I can’t say if it’s related and didn’t have a chance to figure out if the bms has a log and how to get it.

Your suggestion also floats at around that voltage but maybe using a higher bulk charge voltage as a "step" is a good idea that might help the balancer, that I will try.

After reading various things about Lithium including some Pylontech info, I had previously setup my system to charge to 51.5v and then turn off the charger and let the batteries drift down to 80% SOC or so and then cycle them.  Like a mini-cycle.  That seemed to work quite well and I did it that way on the basis that Pylontech said that the best way to store batteries is with mid-charge rather than full or empty.

I will try your approach.

Once my PV is in it will become moot since then I’ll use them as intended rather than floating them all the time.

 

Just one thing to add - Pylontech's alarm LED has just two meanings:

1 - charging protection
2 - discharging protection

So, if the LED is ON and you are charging, it basically tells you that you are pushing too much

 

I was just having the same issue with my bank of 4 Pylons and an Axpert MKS5 - every few days, the master Pylon alarms red and disconnects the batteries. No loads used from the battery side, so no discharging, only float charging. Back to normal after a switch off/on of the master battery. Couldn't see anything triggering this in ICC graphs/logs.

My two charging states were on 53.2V for each, but see @Youda has answered the question I was going to ask - will try setting the CC + CV to 53.2V/52.2V and see if it stops the alarm/disconnect ever few days.

Couple of weeks ago, I just switched my battery bank from 20kWh Winston to 4x Pylon US3000, 14kWh total. And these are the parameters that are working okay for me:

C.C. = 52.5V
C.V.  = 52.0V

No unexpected shutdowns are occuring, batteries are being charged to full, no auto-draining of the battery when it's in the C.V. state.
I will monitor the batteries over couple of months, whether the cells will start to be unbalanced on not. If not, I will stick to this lower charging voltage as I prefer longevity rather than stretching the capacity of the batteries to it's limits

51 minutes ago, Youda said:

C.V.  = 52.0V

That's around 3.45V per cell, which is a really good voltage to work with. Most suppliers take them up to 3.55V per cell, but by then you are past the elbow point and the battery doesn't store much additional energy.

1 hour ago, HowardB said:

I was just having the same issue with my bank of 4 Pylons and an Axpert MKS5 - every few days, the master Pylon alarms red and disconnects the batteries. No loads used from the battery side, so no discharging, only float charging. Back to normal after a switch off/on of the master battery. Couldn't see anything triggering this in ICC graphs/logs.

My two charging states were on 53.2V for each, but see @Youda has answered the question I was going to ask - will try setting the CC + CV to 53.2V/52.2V and see if it stops the alarm/disconnect ever few days.

I've pretty much always uses 52v.

But since I've been cycling my batteries there have been no issues.

 

2 hours ago, Elbow said:

I've pretty much always uses 52v.

But since I've been cycling my batteries there have been no issues.

 

Thanks, have changed to 53.2V for bulk charging and 52.2 for float charge - will see how it goes

5 hours ago, HowardB said:

I was just having the same issue with my bank of 4 Pylons and an Axpert MKS5 - every few days, the master Pylon alarms red and disconnects the batteries. No loads used from the battery side, so no discharging, only float charging. Back to normal after a switch off/on of the master battery. Couldn't see anything triggering this in ICC graphs/logs.

My two charging states were on 53.2V for each, but see @Youda has answered the question I was going to ask - will try setting the CC + CV to 53.2V/52.2V and see if it stops the alarm/disconnect ever few days.

That would be very annoying in an off grid situation.

Quick update:

When set to 53.2V for bulk charging and 52.2V for float charge, the Pylon's SOC shows 99.50% and never gets to 100%. If the float charge is increased to 52.3V it gets to 99.75% SOC and on 52.4V it gets to 100% SOC at 3.5V per cell.

So I've set it to 52.4V on Thursday and so far no alarm - will watch over the next week or so to see if it happens again.

2 hours ago, HowardB said:

52.4V it gets to 100% SOC at 3.5V per cell

In my experience it depends on the internal balance of the batteries. It seems to reset to 100% at 53V (sometimes earlier, but 53V seems to be the voltage if you want to get there "for sure"). 52V on a new battery can show as little as 94%, and over time tends to improve to 96% or more. In the end, the SOC remains an estimation based on  number of internal measurements, and it's one you should perhaps not worry about too much.

All was going well since 20 April with the float charge set to 52.4V, however, got another battery disconnect alarm yesterday morning... any ideas what could be causing this? The load is only 200w or so average (on utility power), and the inverter is effectively a UPS at this stage until I can get the solar panels ordered and installed. 

The battery SOC shows 99.75% per BMS/ICC, with the highest cell voltage at 3.5v and the lowest cell at 3.47v - average is 3.49 according to ICC, so well within the Pylon's range. 

20 hours ago, HowardB said:

All was going well since 20 April with the float charge set to 52.4V, however, got another battery disconnect alarm yesterday morning... any ideas what could be causing this? The load is only 200w or so average (on utility power), and the inverter is effectively a UPS at this stage until I can get the solar panels ordered and installed. 

The battery SOC shows 99.75% per BMS/ICC, with the highest cell voltage at 3.5v and the lowest cell at 3.47v - average is 3.49 according to ICC, so well within the Pylon's range. 

From my side i’ve had no more trouble - probably since I’ve been cycling them after my panels went in.

Set the float down to 52v.  The 1% imbalance is a lot but for me imbalance tended to go away as soon as the cell voltages went down a bit.

@HowardB

How about to run BatteryView.exe when you experience the alarm? BV gives you a bit more insight on what's going on then ICC does.

You will need to disconnect ICC cable as BV uses the same (console) port too...

 

@Youda

Thanks will try that - where do I find BatteryViewer.exe?

Checked all the discs that came with the hardware, but nothing like that included. Can't find anything on the forum either.

Message sent

And here's the cable pinout that you will need probably...

Edited May 7, 20197 yr by Youda

On 2019/04/18 at 12:54 PM, Youda said:

Couple of weeks ago, I just switched my battery bank from 20kWh Winston to 4x Pylon US3000, 14kWh total. And these are the parameters that are working okay for me:

C.C. = 52.5V
C.V.  = 52.0V

No unexpected shutdowns are occuring, batteries are being charged to full, no auto-draining of the battery when it's in the C.V. state.
I will monitor the batteries over couple of months, whether the cells will start to be unbalanced on not. If not, I will stick to this lower charging voltage as I prefer longevity rather than stretching the capacity of the batteries to it's limits

This is quite valuable information. For both the Victron and Voltronic inverters, the manuals state that float voltage should be 53.0V or 53.2V respectively and not 52, or thereabouts as you say. 

Hi Guys (and Gals)

Lately i have been getting an over-voltage alarm on my set up. it's not much, but it's been as high as 54.06. this usually lasts for a minute or 2.

My bulk charge is set at 53.2 and my float charge is set at 52.5

is this something to be concerned about and also why does this happen?

Many thanks in advance

Jason

24 minutes ago, jasonvanwyk said:

My bulk charge is set at 53.2 and my float charge is set at 52.5

That's why we recommend lowering the charge voltage. At 53.2V it's at 3.55V per cell, which is already past the "elbow" point on the voltage chart, that point where LFP cells spike up easily in voltage. Lower it to a lower 3.45V per cell, or 52V.

IMHO C.C. voltage 53.2V is too high for Pylontech. Yeah, I know that they state in their papers that you can charge up to 54,  but that's the very top limit of the BMS itselfs, not the number that's safe to be set on the inverter-charger. When the charger is pushing current into the LFP cell, the voltage raises veeery slowly, but once you reach 3.5V, then the voltage has a tendency to jump-up in a second. Once a cell is above 3.6V, it generates an alarm. So, if couple of cells in the battery are undercharged, then they are still pulling the current. But since they are in series with other cells (that may be already almost charged) this passing current causes overcharging. Pylon BMS can normally stop this with it's internal ballancers, but if the charger is pushing too hard, the balancers cannot keep-up.

I would suggest you to set:
C.C. = 52.5 V
C.V. = 52.0 V

Also, you can monitor your battery during the error with the diagnostic software available here: https://powerforum.co.za/topic/2322-youdas-off-grid-lab/page/2/?tab=comments#comment-53641

By the way - there's an OLD Pylontech paper flying around the internet, that is suggesting too high charging voltages. I bet that you are just another victim of that paper...

Edited May 11, 20197 yr by Youda

On 2019/05/11 at 1:39 PM, Youda said:

 

Also, you can monitor your battery during the error with the diagnostic software available here: https://powerforum.co.za/topic/2322-youdas-off-grid-lab/page/2/?tab=comments#comment-53641

By the way - there's an OLD Pylontech paper flying around the internet, that is suggesting too high charging voltages. I bet that you are just another victim of that paper...

Thanks Youda!