In past I have wasted 3 batteries in a row. It all started with a solar max 1000 watt Inverter. My Electrician gave it when my desi UPS went bad and ruined my AGS 175 after a good run of 2 years. Next, Osaka 200'ish model 27 plate I remember faired so well for 2.5 years on solarmax inverter with 340 to 400 watt load on daily basis. When backup reduced to 1 hour I decided to let the battery go. I had been using that Solarmax for free so I decided to return to my Electrician with thanks and purchased Homage neon 900 watt Inverter.
From here badluck started which actually forced me down the path of battery and Inverter know-how and interest taking in it to some extent. My new Osaka UGS series got ruined by my Homage in almost 8 months when backup reduced to 1 hour. While Homage people said inverter was fine and the battery had the flaw. After some research I concluded battery was culprit and more specifically the electroyte and 1st incomplete charging was reason of its premature death.
I bought VRLA battery 150 AH crown micro and used it along Homage. Battery worked very good in all summers and never went below 50% initially. But I noticed homage would always charge it whenever I checked it. It seemed my draw was more than the time it had available to recharge the battery before next power cutt. Homage had 10-15 amp charging switch which was kept at 15 all the time. I actually have a PC with bigger power supply and a 3d graphics card which activates when I play any video. Load exceeds 500 watt when that graphics is decoding videos for playback.
Anyways summer went by and during winters didn't use inverter much only to come to know in next summers that my VRLA a 25k investment had gone kaput giving only 1 hour of backup. Immediately claimed the warranty and got replacement for free. New sealed lead acid battery repeated the same story worked well for 1st year or two seasons and backup started to reduce. I changed my routines and stopped using my PC on the battery power. Somehow I used that for another year and got rid of it when backup time hit 30 mins. During this time I keenly watched it go down so did good research afterwards to conclude on reason of death of my 2 VRLA and 1 FLA battery. Well to me it was Under Charging vs. load I ran on it vs. the time slots available in between consecutive power cuts.
So this time I wanted something planned and thoughtout beforehand. I went APC this time. 980 watt as per my usage requirements. Model APC Smart UPS SMT-1500i lcd one. Bought new Phoenix XP-145 batteries in pair as I had jumped from 12v to 24v backup plan. Used Phoenix on APC for 1 month and discarded Phoenix as well. Voltage seemed to drop at 11.8vdc underload on 1 of the 2 batteries. Other was perfectly fine though. This left so much bad taste in my mouth. Why would I feed by great APC Ups with malfunctioned pair of batteries. So got rid of those Phoenixis. Another problem I had was Specific Gravity of them set to 1230 at purchase time and never exceeded 1250 max with full charge. Either the electrolyte solution was weaker or its 1st charge by dealer was not Full as required. Remember this first charge is the deciding factor on life of a FLA battery after electroyte is poured in and most important after the electroyte quality and specific gravity. Moreover, APC had max charging current of 12 amps which is just hardly enough for a 120 A.H size battery if its given ample of Recharge times. Example, 1 hour loadshedding​ then 4 hours relaxation and so on. But here it is not the case. Sometimes light comes n goes so frequently that C/10 charging current method (capacity in AH divided by 10) is truely not enough to fix your problem. You need almost C/5 charging current to keep up with loadshedding here. That is, for a 100 AH battery in 12v single battery system you need atleast (100/5) 20 amps charger power and in 24v system it would be similar 20 amps charging is required on a pair of 100 AH batteries connected in series. So my next plan was to implement C/5 charging which is true for true deep cycling...
Now I want my batteries to be long life as I maintain them good with voltage readings, specific gravity readings and have temperature gauge on battery to measure battery temps. Heat is the biggest threat to any kind of battery. We can't change Pakistan's weathers however there is another thing you can do to increase battery life is to control depth of discharges in such a way that your typical loadshedding hour usage do not exceed 20% of your battery bank capacity in most instances and in few cases where you need high use it shouldn't go below 50% state of charge. Even knowing what you got is a deep cycle battery still avoid going 80% Dod if you are looking at 3 years of life.
Next came the decision on battery size with above recommendation of DoD and Battery type (FLA, AGM, VRLA). Here cost factors also play role. Material wise I knew there is nothing tougher than Fat Tubular plates in a tubular FLA battery. On other hand those Gel Agm and Vrla types wouldn't like to see below 50% Dod frequently and also recover with efficiency as that of Tubular. Li-ion batt would serve all purposes the best way but due their cost upfront not included them in the mix. So finally Tubular with minimal 160 AH capacity on 24v system would serve well. Almost equal to a 320 AH backup. I would now enjoy quite a few less than 20% DoDs. Yes! --- Also the Osaka comes filled up with branded electrolyte and 1st charge is already done at factory is a BIG plus point for me. Osaka mesures 12.65 volts on open circuit out of the box new in complete cold resting state. I stress testes before purchase at shop and they stood 12.5 at 100 watt halogen bulb load for 3 minutes. Specific gravity measured 1255 out of the box and 1280 after full charge state after 72 hours of Float mode on charger.
Now came APC charging current problem, its charger didn't support my bigger fatter tubular battery bank of Osaka Tr1600s. Therefore, let the good guy depart from us. And bought new micro processor controlled fully adjustable variables charger with 30 amperes of power minimum by C/5 formula on my Tubular bank. This wasn't charger alone rather chinese new generation hybrid inverters which have this grade of charging where user can set Bulk, absorption, float voltages to suit different types of batteries i.e. AGM, VRLA, Flooded Lead acid (common one) and also have Battery Profiles to select to automatically select suitable charging profile. This is what saves a battery from under charging that you provide it correct voltage that it requires as per its type with good amount of current (C/5) to fight away with Loadshedding schedules in Pakistan. Which is in other words Intense Cycling to medium intense cycling depending upon your Load requirements and frequency of power cuts. These hybrids are mostly imported by Voltronic Power and APT China and sold here under different distributions like Inverex, Solarmax and Crown micro. One I got is Crown Nero 3kW model with solar low grade charging that I also do not require at this time. It has Battery Equalization function as well and has Equalization scheduling. Equalization is actually a controlled timed over charge done on batteries to refresh them after 2 or 3months when they get stressed due to frequent cycling and heavy usage.
Here goes my new setup Osaka 160 AH Tubular batteries on Crown Micro Nero Hybrid 24vdc inverter 3kw, with my old APC setup as well shown with an external Eltek Rectifier I installed sadly it didn't have float stage in it so not safe for usage as battery maintainer charger.
Old APC with Eltek 24/48v 30 amps charger on pair of TR1600 Osaka Tubulars
New Crown Nero Hybrid inverter 24v 3kw.
