The Batteries are a vital part of your Home UPS inverter system and constitute a large portion of your out lay. The life span of you battery or battery bank will largely depend on the quality, type of the battery and how well you look after the batteries. Incorrect charging, lack of maintenance or deep discharging are battery killers. Make sure the inverter you chose has a proper charge controller and low discharge battery protection.
Requirements of an Inverter Battery
Ability to withstand frequent deep discharge.
Reliability over years of operation.
Minimum emission of gases/fumes
Capacity of a battery is expressed in terms of Ampere Hour (Ah). It indicates the rate of current a battery can supply for a given duration. If the capacity of a battery is 100 Ah, that battery can supply 100 Ampere current for 1 Hour or 1 Ampere Current for 100 Hrs, 2 Amps Current for 50 Hrs .Capacity of inverter batteries are generally 100 Ah, 150 Ah or 180 Ah.
Why automotive batteries are not suitable for inverters?
Lead acid batteries used for automotive purpose are designed to provide high current for a very short duration (to start the vehicle). Automotive lead acid batteries are not designed to be regularly discharged by more than 25% of their rated capacity. The requirements of inverter systems are totally different. Inverters require “Deep Cycle” batteries to provide continuous power which can be discharged at least 50% of their rated capacity. Some good deep cycle batteries can be discharged over 70% of their capacity. Deep Cycle batteries have specially designed thick plates to withstand frequent charging and discharging.
Sealed Maintenance Free batteries (SMF)
Normal lead acid batteries require regular maintenance. During charging and discharge lead acid batteries release gasses and need to be very well ventilated.
Home inverters generally use maintenance free batteries which are sealed lead acid batteries which do not require regular maintenance or additional ventilation.
Tubular Batteries are becoming more popular for Home UPS systems and have several advantages compared to flat plate batteries. A more complex design increases the manufacture cost but the high electrical efficiency and extra long life make tubular batteries suitable for both domestic and industrial applications. Good tubular batteries can last unto 2, 3 or 4 times as long as lead acid batteries. The cost of tubular batteries can be up to double that of a lead acid battery, however if you have a high efficiency inverter then go for a tubular battery, you will not regret it.