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Costa

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  1. 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
  2. Note 2: My subsequent (hasty) attempt to replace the automotive relay with a high power solenoid/contactor used on a motorbike starter motor ... also failed miserably. In my haste, I completely overlooked the duty-cycle! The starter solenoid is designed to deliver 300-400 amps for 4 seconds and then cools down till the next time. The starter solenoid will effectively cook itself to destruction, just from being energised continuously – even with ZERO amps current draw from the battery! I wasted way too much time and money on this dead end...but I did have lots of fun!
  3. Hi Paulus, Funny you should mention this Yes, I eventually ended up looking at the Arduino ecosystem…I actually started playing with them for the first time a few weeks ago…more about this in a moment; The tests that I conducted between Nov – Dec 2020 were crazy time consuming! Not a sustainable nor practical way to do it….but I didn’t want to spend the next few weeks-months figuring out the Arduino stuff…so I opted for a different interim solution: Battery Capacity Testing Tools v2.0 Step 1: I upgraded my 600W “light emitting heater” with a 100A s
  4. Richard, I think you are correct. The classic "wet cell" lead-acid batteries probably deliver a decently long life (assuming you put in the required effort to rigorously maintain them). Since the average consumer neglects the batteries (due to the laborious effort required to maintain them) it is understandable that the emergence of “maintenance free” sealed type lead-acid batteries have been very well received. In effect, the design of sealed batteries have struck a different balance of compromises between user convenience vs “ultimate long life”! Yup...good for battery sa
  5. 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 + batt
  6. Part 2.4 – Summary and status of what has been done so far My 48v inverter + 4x200Ah batteries were installed in Dec 2018 (without a battery balancer) My average load on the inverter is ± 500W – therefore the average current draw on the battery bank is ±10A According to the battery datasheet, these batteries are able to provide 10A continuously for 20hours (100% DOD - depth of discharge) Based on my required runtime of 9-12 hours @ ±10A, we can roughly expect a 45% - 60% DOD Less than 2 years after installation, the battery capacity is unable to sustain ±10A for 4
  7. Hi Speedster. Thank you for sharing the link to the charger. Despite the cryptic details and specs, you’ve got me pondering to get one too. The price is pretty good too at the moment. You say you have had good success with it on the 7Ah batteries? If you’ve been able to extend the life of two-three batteries then it’s basically paid itself off!
  8. Part 2.2 – Actions taken BEFORE proceeding to evaluate the desulfated batteries “Insanity: Doing the same thing over and over again and expecting different results!” So, before proceeding to reconnect the freshly rejuvenated batteries, I was still concerned with understanding “why” my AGM batteries failed prematurely (failed to achieved 2 full years service) in the first place! · The inverter is always on/standby (AC power from the grid). Therefore the batteries are always fully charged and maintained/floated by the multi-stage char
  9. 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)
  10. 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
  11. Part 1.3 – What Exactly is Sulphation and De-Sulphation? In summary: 1) What is Sulfation? According to the Battery University (BU-804b: Sulfation and How to Prevent it “During use, small sulfate crystals form, but these are normal and are not harmful. During prolonged charge deprivation, however, the amorphous lead sulfate converts to a stable crystalline and deposits on the negative plates. This leads to the development of large crystals that reduce the battery’s active material, which is responsible for the performance.
  12. Before delving into Part 2 (Desulphation stuff etc), I need to first fill you in on the following details; Part 1.2 - Individual Battery Capacity Testing and the DIY Tools (V1.0) used. I think everyone would agree, that the performance indicated by the tests dated 14 - 18 Nov 2020 are terrible. But what exactly is the theoretical “normal” performance that I should have seen? According the datasheet for the Allgrand 200Ah AGM battery: This battery is rated as a 200Ah battery because it is able to deliver 10A continuously for 20hours (10A X 20h = 200Ah). It is consider
  13. 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.
  14. 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 200
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