Costa

In summary: with Battery Capacity Test Tool V2.0,  have been turning the 600W light ON-OFF manually by hand. Start the test, the datalogger records the battery voltage vs time. Listen out for the buzzer, then go and witness the last few minutes of discharge till the cut-off voltage and finally switch off the lights (manually).
 
Spoiler alert 1: I have used this setup to revive and evaluate my old Deltec 200Ah batterieis and another set of Allgrand 200Ah that are installed at my father-in-law (more about those results in a future post).
Spoiler alert 2: I am busy playing with an ESP8266 (similar to Arduino) + OLED screen + INA219 current & voltage sensing board + microSD card, to build a comprehensive datalogger setup (V3.0). Im already sitting at over 900 lines of Arduino code. The baby shunt on the INA219 will eventualy be replaced with my 100A shunt. This is intended to also switch the 50A load via a software controlled cut-off voltage.

Part 2 – My Desulfation efforts and mixed results
Armed with the following desulfation tools:
Adjustable PSU CTEK charger MXS5 Multimeter And a desulfation strategy summarised as follows:
     Step 1 – Bulk, absorb and float charge the battery (with either the PSU or CTEK)
     Step 2 – Use PSU re-check float charge and confirm that battery has absorbed (float charge current should drop to less than 0.2A)
     Step 3 – Pre-Set the PSU to an open circuit voltage of 15.89V (check with multimeter)
     Step 4 – Connect the PSU to the battery to start the desulfation.
                    At this point, the battery would accept all 10A but I set the PSU to CURRENT LIMIT @ 4A (roughly based on the Lifeline battery guidelines)
     Step 5 – Monitor the desulfation process and stop/abort:
                    a)       If there is excessive venting/gassing (subjective). The Allgrand batteries make a whistling sound when they vent.
                    b)      If the battery becomes abnormally warm/hot (subjective)
                    c)       If the battery voltage drops below 15v (desulfation only effective above 15v)
                    d)      After 8 hours (based on the guidelines from Lifeline)
 
The following voltage and current curves indicate the principle behaviour observed when my Allgrand batteries were being desulfated:

Hello Guys and Girls,
I am new to the forum…this is my second post. I gave a brief intro in my first post (Power Forum - Axpert King 5kW - Warning 32 )
 
In this writeup, I would like to share my experiences with trying to revive (desulphate) my otherwise kaput 200Ah AGMs!
 
 
Part 1: Background Info
 
My current system (V2.0) consists of a 5kW Axpert King & 4x 200Ah Allgrand AGMs. It’s purpose is to provide clean power and UPS to the essential stuff in my home. I installed it in Dec 2018 as an upgrade/replacement of my 1kW 24v Microcare & 2x 200Ah Deltec AGMs, which have served me since Dec 2014. The upgrade was triggered because after 4 years service, the Deltec’s had lost capacity and the backup runtime had become unaceptable!
My definition of “essential stuff” is all home lighting, alarm system, electric fence, gate motors, CCTV, computers, network, internet, TV and last but not least the fridge. My average load is approx. 400W-500W. It drops to minimum of 280W and climbs to a max of around 600W (ignoring the startup load of the fridge).
My required max runtime is between 9-12hours, ie to make it through the night. We have occasional power disruptions (once or twice a year) that last 24 hours and every other year we loose power for 2-4 consecutive days! This lovely reality is courtesy of City of Jhb and the aging infrastructure combined with cable theft and substation vandalisms!
I have a 9KVA generator that enables me to bulk charge my batteries for 4h in the morning and 4h hours at night and make it through the couple of days of ESKOM power disruption.
My upgraded system migrated to:
48v, in order to double up on the previous battery capacity (and hopefully improve the disappointing 4y service life of the Deltecs). The Axpert KING inverter, because of the 0ms transfer time as well as the healthy AC charging amps (for a good dose of 30A bulk charging during those 4hours of generator run-time). The built in MPPT is a nice to have for future upgrade/expansion. Back to Reality
 
The 200Ah Allgrand AGMs barely lasted 2 years (disappointment is an understatement). They did not work hard during these two years. From my recollection and perception, they were not cycled many times either, unfortunately I do not have exact data to refer back to. They most definitely were not deep cycled “hundreds of times” as per the performance promises indicated on their datasheet!
I will discuss my speculations of the root cause of their failure in a later part of this writeup.
After experiencing a premature shutdown during load shedding, I started investigating and ran the following capacity load tests with a >2kW load (courtesy of a two element air heater):
 In summary, with a draw of 50A from the batteries I was getting less than 15min runtime!
These batteries are truly kaput! Specifically battery no 1 was collapsing prematurely and it's voltage was rapidly falling off below 10v!



 

In summary: with Battery Capacity Test Tool V2.0,  have been turning the 600W light ON-OFF manually by hand. Start the test, the datalogger records the battery voltage vs time. Listen out for the buzzer, then go and witness the last few minutes of discharge till the cut-off voltage and finally switch off the lights (manually).
 
Spoiler alert 1: I have used this setup to revive and evaluate my old Deltec 200Ah batterieis and another set of Allgrand 200Ah that are installed at my father-in-law (more about those results in a future post).
Spoiler alert 2: I am busy playing with an ESP8266 (similar to Arduino) + OLED screen + INA219 current & voltage sensing board + microSD card, to build a comprehensive datalogger setup (V3.0). Im already sitting at over 900 lines of Arduino code. The baby shunt on the INA219 will eventualy be replaced with my 100A shunt. This is intended to also switch the 50A load via a software controlled cut-off voltage.

In summary: with Battery Capacity Test Tool V2.0,  have been turning the 600W light ON-OFF manually by hand. Start the test, the datalogger records the battery voltage vs time. Listen out for the buzzer, then go and witness the last few minutes of discharge till the cut-off voltage and finally switch off the lights (manually).
 
Spoiler alert 1: I have used this setup to revive and evaluate my old Deltec 200Ah batterieis and another set of Allgrand 200Ah that are installed at my father-in-law (more about those results in a future post).
Spoiler alert 2: I am busy playing with an ESP8266 (similar to Arduino) + OLED screen + INA219 current & voltage sensing board + microSD card, to build a comprehensive datalogger setup (V3.0). Im already sitting at over 900 lines of Arduino code. The baby shunt on the INA219 will eventualy be replaced with my 100A shunt. This is intended to also switch the 50A load via a software controlled cut-off voltage.

Thanks Costa for your post, it was helpful in trouble shooting my Warning 32 , on an Axpert 5kw King after installing some fresh Pylontech batteries.
After several attempts to boot without this Warning 32 , I gave up and called it a day.  It was highly frustrating , I disconnected batteries and PV solar strings and attempted a clean boot many a time from the battery power, to no avail.
On return the next day I decided the only thing left to do to get a clean boot without this error is to FIRST disconnect my AC Input voltage completely, the PV string and batteries were already off the entire night . And presto, on first start I had no Warning 32 the next day!
I surmise that the AC Input was keeping something alive in the Axpert enough to hold the warning in memory, even though the batteries were off for longer than 5 minutes the day before, and the unit appeared absolutely powered off. Perhaps you really need to rest the unit for a stubbornly long time to get all the caps drained!   i.e. hours ! We know that this unit can ONLY be powered up by a battery , but this situation perhaps suggest that the AC input has a small enough effect to keep the warning 32 in memory?  -Just my opinion.
My suggested solution for anyone else having this problem, would be to disconnect the PV solar strings, AC Input, and then the batteries and watch the unit power off. Wait as long as you can . Then power up the batteries only to get the clean boot and no warning 32. Switch on your PV Input and AC Input once the unit has settled.
 
 

The improvement in battery capacity indicates that, to some degree, sulfation had been reversed. My hypothesis for the root cause of the pre-mature battery failure is that, in the absence of a battery balancer within a bank of batteries, the weak battery will keep getting undercharged and will progressively sulfate and get weaker and weaker. This will eventually spiral out of control and lead to the destruction of the whole bank of batteries! I added the HA02 battery balancer, then reconnected and powered-up the inverter. I repeated the capacity tests with the inverter + battery bank at an average inverter load of 450W (the current draw from the batteries was on average around 10A). The runtime had improved to 8h 40min! Not too shabby! (refer to the graph below for moredetails):  

 
8hours 40min runtime @ 10A vs a theoretical maximum 20h @ 10A indicates a battery bank health/capacity of 43%  
I also installed a shunt and an energy meter (ill share closeup photos in a future post) and recorded that the batteries had in fact delivered 3896Wh during the above test. A crude estimate of the (theoretical) maximum stored energy in a 48v 200Ah battery bank = 48*200 = 9600Wh. Interestingly, the measured capacity vs theoretical capacity also indicate a battery bank health/capacity of 40%! Not a bad improvement for batteries that are technically kaput!
 
I wouldn't trust them to carry me through the night, but they should be fine for 2h or 4h of load shedding!

So after desulfating the batteries one by one, I repeated the individual battery capacity tests. The following graphs show the performance:
Before desulfation:    29-30 Nov 2020
After desulfation:       01-06 Dec 2020

All 4 batteries achieved a runtime of more than 2.5hours with the same 50A continuous current draw!
Taking a closer look at Battery #1   Before & After:
29 Nov 2020 - Runtime         14m30s - 12Ah (8% capacity relative to the datasheet 150Ah)
01 Dec 2020 - Runtime     2h36m10s - 130Ah (86.6% capacity relative to the datasheet 150Ah)
 
Needless to say, I was really chuffed with these results!
I couldnt wait to power up the inverter and repeat the system test.
I was also exhausted from the old-school "paper, pencil & stopwatch" method of data capturing. This required urgent action to automate the testing and also to add datalogging (I was planning to run more tests...more on that in the next part)
 

Lol. I see my link failed. This is the one I bought
https://banggood.app.link/RNqckiQSYdb

Really fun project to read. Thanks for sharing!
I bought one of these a while back, the pulse repair function helped save some of my small (7Ah) lead-acids. 

So after desulfating the batteries one by one, I repeated the individual battery capacity tests. The following graphs show the performance:
Before desulfation:    29-30 Nov 2020
After desulfation:       01-06 Dec 2020

All 4 batteries achieved a runtime of more than 2.5hours with the same 50A continuous current draw!
Taking a closer look at Battery #1   Before & After:
29 Nov 2020 - Runtime         14m30s - 12Ah (8% capacity relative to the datasheet 150Ah)
01 Dec 2020 - Runtime     2h36m10s - 130Ah (86.6% capacity relative to the datasheet 150Ah)
 
Needless to say, I was really chuffed with these results!
I couldnt wait to power up the inverter and repeat the system test.
I was also exhausted from the old-school "paper, pencil & stopwatch" method of data capturing. This required urgent action to automate the testing and also to add datalogging (I was planning to run more tests...more on that in the next part)
 

Hello Guys and Girls,
I am new to the forum…this is my second post. I gave a brief intro in my first post (Power Forum - Axpert King 5kW - Warning 32 )
 
In this writeup, I would like to share my experiences with trying to revive (desulphate) my otherwise kaput 200Ah AGMs!
 
 
Part 1: Background Info
 
My current system (V2.0) consists of a 5kW Axpert King & 4x 200Ah Allgrand AGMs. It’s purpose is to provide clean power and UPS to the essential stuff in my home. I installed it in Dec 2018 as an upgrade/replacement of my 1kW 24v Microcare & 2x 200Ah Deltec AGMs, which have served me since Dec 2014. The upgrade was triggered because after 4 years service, the Deltec’s had lost capacity and the backup runtime had become unaceptable!
My definition of “essential stuff” is all home lighting, alarm system, electric fence, gate motors, CCTV, computers, network, internet, TV and last but not least the fridge. My average load is approx. 400W-500W. It drops to minimum of 280W and climbs to a max of around 600W (ignoring the startup load of the fridge).
My required max runtime is between 9-12hours, ie to make it through the night. We have occasional power disruptions (once or twice a year) that last 24 hours and every other year we loose power for 2-4 consecutive days! This lovely reality is courtesy of City of Jhb and the aging infrastructure combined with cable theft and substation vandalisms!
I have a 9KVA generator that enables me to bulk charge my batteries for 4h in the morning and 4h hours at night and make it through the couple of days of ESKOM power disruption.
My upgraded system migrated to:
48v, in order to double up on the previous battery capacity (and hopefully improve the disappointing 4y service life of the Deltecs). The Axpert KING inverter, because of the 0ms transfer time as well as the healthy AC charging amps (for a good dose of 30A bulk charging during those 4hours of generator run-time). The built in MPPT is a nice to have for future upgrade/expansion. Back to Reality
 
The 200Ah Allgrand AGMs barely lasted 2 years (disappointment is an understatement). They did not work hard during these two years. From my recollection and perception, they were not cycled many times either, unfortunately I do not have exact data to refer back to. They most definitely were not deep cycled “hundreds of times” as per the performance promises indicated on their datasheet!
I will discuss my speculations of the root cause of their failure in a later part of this writeup.
After experiencing a premature shutdown during load shedding, I started investigating and ran the following capacity load tests with a >2kW load (courtesy of a two element air heater):
 In summary, with a draw of 50A from the batteries I was getting less than 15min runtime!
These batteries are truly kaput! Specifically battery no 1 was collapsing prematurely and it's voltage was rapidly falling off below 10v!



 

Part 2 - My Desulphation efforts and the mixed results (to be continued tomorrow)
Teaser: The desluphation strategy that I applied resulted in the following improvements as achieved in the test results dated 20 Dec 2020
ie almost 9hours runtime while powering the normal loads connected to the inverter!
Details of the desulphation strategy and info on the DIY tools used will follow in Part 2.

 

I pushed the "Like" button for your pre-charge arrangement. Your setup was a bit easier as you only have 1x fuse.

Hello Coulomb, Thank You for your response.

Yes, the pre-charge was already in place and I have been using it meticulously.
Apologies for my oversight in refering to Warning 32 as an Error (I will edit the post and rectify accordingly).

 
Some additional info (possibly relevant) regarding the power down that preceded the occurrence of Warning 32;

I had just completed another round of individual battery capacity tests, but due to unforeseen delays, this had taken much longer than planned and I had started partially charging the 2x batteries that were sitting discharged for more than 5hours. Once the 4th battery was also ready for recharge, I powered up the KING to recharge the lot. I immediately observed an overvoltage condition on one of the batteries (>16V) due to the very unbalanced SOC’s of the 4 batteries. So in my haste/panic, I botched the power-down sequence. I first disconnected the DC fuse to stop the charging . I recall the KING hovering in charging mode, trying to deliver 56.8v into an open circuit. I waited a few seconds and it just hovered in charge mode. I then cut the AC supply to the KING and abruptly shut it down!

The more I think about it, it is most likely that this is what caused the Warning 32 which appeared on the next power-up! (ie interrupting the DC before the AC). (Doesn't the KING's display processor also handle the comms with external battery BMS's?....perhaps the Warning 32 was referring to loss of battery DC & comms as opposed to an LCD warning)