BATTERY IS NOT CAPABLE BEING CHARGED BY INVERTER. Review on Choosing an Inverter

An inverter does two main functions.

(i) It Converts 220V AC to  12V DC and stores the charge into battery.

(ii) When there is no power, it converts 12V DC to 220V AC.

Batteries are available in different capacity such as 100AH, 120 AH, 150 AH / 12V DC etc. Battery of 150 AH having 80% efficiency, should able to deliver 40A discharging current for 3 Hours.(i.e. 120/40).

If you connect the following loads: 3 Ceiling Fans and 4 Tube lights then  it would amounts to(3 x80 VA+ 4x60 VA)= 480VA.(to convert Watts into VA, apply additional 20% on watts. eg. Fan 60-70W= 72-84VA) .  So, the above load will take as near to 40A(480VA/12V) current from battery.(It can be very well confirmed by connecting DC ammeter).  If 150 AH battery is fully charged, then for the above load, it should support minimum of 3Hours and maximum of 3Hours 30Mins.(Another Eg: If you connect 2 Fan 2 Tube, ( 2 x 80+ 2 x 60)=  280VA= discharging current of 24Amps.  On this load, 150AH battery should support a back up of minimum 5 Hrs and maximum of 6Hrs 30 Mins.) The branded batteries are being sold specially for inverters. So, the battery must be capable of being fully charged by inverters. If 150AH  battery is charged for 24 hours(excluding power cut time) without used in Inverter Mode by charging voltage of 14.4 and initial charging current of 10-12Amps(most of the inverters available in the market are having above specifications), then theoretically the battery should be charged to its full capacity of 150AH.  But, practically when battery is charged by an inverter, it charges to maximum of 80-90AH only.  Applying above load, 80AH charged battery  gives only 2 hours backup. When above test is carried out, ONLOAD battery terminal voltage initially, is somewhere around 11.90V, after 1 hour around 11.70V  and after exactly two hours, it gets cut off at 10.50V(most of the inverters are designed for cutoff at 10.50V).

So, you pay money for 150AH battery but actually you get only 80-90AH capacity out of 150AH.  Even, you charge the battery for 5 days, the above condition still prevails. I have tried with  many batteries and different inverters, but the fact is that so far, no inverter could able to charge the battery to its full capacity. When I take the issue to my battery supplier, they  simply escape by saying that due to power cut, battery is not able to charge to its full capacity.  That is not a real fact. Today, not a single branded battery(ordinary or tubular) is designed to charge to full capacity BY AN INVERTER(14.4V Charging Voltage and initial charging current of 10-12A).  But, when I made this as a serious complainant with battery supplier, in order to convince me,  they put the  battery on'Bench Charge' i.e. constant current charge with ultimate peak charging voltage of 16.5V at their shop(which is not possible by inverters) and brought the battery to full capacity of 150AH. Now, when I tested with the above load, it gave 3H 30Min backup.  There is no doubt that battery is actually manufactured to have 150AH capacity BUT  NOT DESIGNED TO CHARGE TO ITS FULL CAPACITY BY AN INVERTER. When the manufacturer  specifically state in their broucher  that   battery should be re-charged through an Inverter at constant potential mode of 14.4V and after battery potential reaches 14.4V, the battery should continue in float charge mode at constant potential of 13.8V, why the branded battery not being charged to its full capacity even if it is left for 5 days of continuous charge? A consumer cannot take the battery every time to the dealer for Bench charge to bring it to its full capacity?   Due to non charging of battery to its full capacity by an inverter, a consumer is at loss, for his 40-45% of money.  When Battery manufacturer  gives three years warranty, people are fascinated with warranty without knowing the charging ability of the battery.

Technically, if a new battery is being charged only to the maximum of 80-90 AH i.e. around 55-60% of capacity, after one year, the  unused portion i.e. remaining 45-40% capacity would be lost its chemical action, called sulphation, which cannot be get back in future. I have been discussing here, charging of a new battery  only to the level of  80-90AH  out of 150AH. Now, just imagine what would be the charging capacity after two years?   My battery supplier, when I argued this concept of backup, they initially complained about the inverter. So, asked them to connect whatever inverter they wish on their battery for charging the battery to its full capacity.  As the battery supplier couldn't succeed to my challenge,   he simply took his battery and paid me the cost. The battery manufacture takes advantage of the present power cut and sells the battery, which is not capable of being charged to its full capacity by an inverter. Sometime, battery supplier blame power cut and sometime they blame the inverter manufacturers. MY CONTENTION IS THAT WHEN A  BATTERY IS NOT CAPABLE OF BEING CHARGED TO MAXIMUM OF ITS CAPACITY, BY AN INVERTER WHICH IS DESIGNED AS PER SPECIFICATIONS GIVEN IN THE BATTERY BROUCHER, WHY IT IS MARKETED BY SAYING THAT IT IS SPECIALLY MADE FOR INVERTER?  AS PER CONSUMER PROTECTION ACT,  THE WRONG PROPAGANDA TO A CUSTOMER ABOUT THE PRODUCT ITSELF AMOUNTS TO DEFICIENCY OF SERVICE.  WHEN THEY SELL BATTERY FOR INVERTERS, IT MUST BE CAPABLE OF BEING CHARGED BY AN INVERTER NOT BY BENCH CHARGE AT BATTERY SUPPLIER'S SHOP. It is the duty of Battery manufacturer who make the battery for inverters, to prove their batteries are capable of being charged to its full capacity by an inverter available on the market or at least they should recommend the particular brand of an inverter which achieve the same effect. When you buy a brand new battery. You carry out above test(keep the inverter switch off) and confirm yourself to know the real capacity of your battery.  (If you have frequent power cut and the battery is being utilized intermittently, try the above test when you leave for 2/3 holidays).

THIS IS THE MAIN REASON WHY WE DON'T GET SUFFICIENT BACKUP FROM THE BATTERY. Many inverter user say, their battery really support them in power cut.  But, whether the battery really charges to its full capacity, can only be ascertained giving above load and noted down the back up hours.  Unless you ascertain the capacity of the battery with above load, you are wasting the real capacity of the battery after paying the full cost for the battery. I have  tried with the inverters of battery manufacturer, even then, there was no chance for full capacity charge. When the above problem is taken to the supplier, sometime, they suggests you for an extra  charger. Even I have tried with automatic extra charger, but again it is no use.  Because, automatic charger only do the same function of inverter charger.

Whatever, I have narrated above, is based on my own experience with different brand inverters and battery to utilize the battery to maximum charging capacity. But,  if any one confirm that his battery reaches full capacity after carrying out the above test, please let me know the name/brand of the battery(AH) and inverter(VA), alongwith the data of load connected and time of back up experienced etc, so that I wish to purchase the same. If anyone disagree with my views, please come forward so that I could correct my views on this issue. With kind regards //// please also refer'two'comments, posted on 16th instant regarding type of charging  ///