A battery is a vital part of an inverter. The performance of an inverter largely depends on its battery. Regular care and maintenance of batteries keep them in good shape for a longer time period. There are several reasons behind why your inverter batteries die earlier than expected.
Excess usage
Life span of a battery is very much dependent upon how much it is used. Batteries wear out faster when used too much. Inverter utilizes the energy stored in batteries and supplies current to the electrical and electronic devices to keep them running during power cut. The more load or devices you use during power failure, more power will be sucked out of batteries and they will wear out faster.
Poor quality battery charger
An inverter unit has 3 components: a charger, a battery and an inverter. The charger is connected to the power supply and it charges the battery when the electricity is coming from the utility. A poor quality charger can destroy the battery faster than anything else. Use good quality chargers to increase life of battery.

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Overcharging battery
Overcharging leads to corrosion of battery plates which eventually results in premature battery failure. If your battery is getting too hot, it is an indication that it is getting overcharged. Overcharging a rechargeable battery leads to its early than expected failure.
Deep discharging the battery
Deep discharging is not good for the health of any rechargeable battery. For example deep-cycle batteries like a lead-acid batteries are designed to be regularly deeply discharged using most of its capacity. A battery looses its efficiency and capacity when it is subjected to deep discharge.
Lack of regular maintenance
Poor maintenance is a major reason behind battery damage. Rust, corrosion and dryness are biggest enemies of your inverter battery. Rusting in terminals reduces the current flow to and from the battery. This restricted flow of current results in slow battery charging which ultimately reduces battery life. Batteries also require regular topping up with distilled water and cleaning. If top-up is not done than battery plates get dried. Dry batteries cannot be saved from failure.

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Electrolyte leakage
It is very important to inspect inverter batteries regularly for any damage and fault. Sometimes the electrolyte leaks through cracks developed in battery. Due to lack of electrolyte the batteries fail.
It is important to understand why your inverter batteries die earlier than expected, so that you can take right actions on right time to extend their life.
For more information inverter and battery performance visit Ideas by Mr. Right
If you are having a hard time with your inverter or battery, connect with Mr.Right.
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A lead acid battery only has about 300 full discharge cycles. If fully discharged and left that way over a few hours will greatly drop its capacity. If discharged lightly you might get full amp hour rating but at a draw of 100amps for a 100ah and 5 amps for a 5amp hour and 1 amp for a 1 amp hour battery you get about 1/3 of the hours you would expect. Higher load means faster it goes bad. 100w on a 100 amp/hour battery is about 13 amps so it might go 8 hours if new. a 5 year old battery can be considered junk as the acids tear up the plates in 4 to 6 years.
Totally agree with you