How long will an inverter battery last?
The answer is simple: it depends on how you treat it!
Here we will give you some tips on how to maintain your inverter battery, increase it’s working lifespan and ensure that it functions properly when the mains supply has failed. In this article, we examine and share with you, those important factors which determine just how long you can expect an inverter battery to last.
What is an inverter battery used for?
Not so long ago, the inverter battery was predominantly used in commercial applications such as power stations and the automotive industry for backup power. Nowadays, we see more and more private households utilizing this convenient energy source as a solution for power cuts or where mains electricity is not accessible. As a leading supplier of lead-acid batteries in India and many other countries, we understand domestic customer requirements more than most. As the national grid supply in many countries is often unpredictable, the general populace has a need for a long-lasting, fairly priced energy storage product that won’t let them down.
Batteries for this sector have to be reliable rugged and sufficiently abuse-resistant without posing a public safety hazard. Batteries release their stored energy as direct current (DC) which is incompatible with the alternating current (AC) delivered by mains supply. Alternators and transformers are used to convert DC to AC making the power supplied by the battery compatible with the mains feed into a building and run the various electrical appliances which use the AC supply. They are used in industries where an uninterruptible power supply (UPS) is needed, such as residential homes and housing units. There are many countries even today where the general populace still relies on battery backup for protection against a failure of mains power.
Typically, a home UPS inverter system stores electrical energy in rechargeable DC cells to provide several hours of essential power during power outages. During the time that the battery is not used when there is a mains supply the cells are trickle charged with low current via a transformer. When the AC supply fails, the inverter battery combination supplies AC power within microseconds to ensure a virtually uninterrupted transition from mains to stored battery energy. A surge protection system is incorporated which prevents spiking, caused by sudden over or under-supply of electricity due to contact and switchgear sparking or mains and battery surges. Inverter batteries have an efficiency rate of around 85-90%.
The losses arise from the internal resistances which give higher on charge voltages compared to discharge voltages. The efficiency is the ratio of watt hours out of the battery (on discharge) divided by watt hours into the battery (on charge).
What factors influence the life of an inverter battery? “Before we decide to buy, what’s the inverter battery life please?” “
The number of times we at Microtex have had that question asked of us is mind-boggling. We want to be as helpful as possible, but the truth is, battery life can vary depending on a host of things, such as the quality of your battery, the charge, how well your battery has been maintained and more.
Among other factors, how long an inverter battery lasts is ultimately dependent on its size, construction, how much is energy is regularly taken out, its working temperature and how old it is. The best answer we can honestly give to this question is: It will last for however long our guarantee is. We know from our experience and feedback just how reliable our inverter battery is proving to be to countless satisfied customers. On the other hand, if the question is “How long will my 150AH battery last on discharge?’ then the answer is a little more straightforward.
In a perfect world, a 100AH battery would last 20 hours with a constant 5 amps load We all know that the world isn’t perfect, so calculations can only be guidelines. Though we say a ‘little’ more straightforward, as it depends on how good you are at arithmetic! Some calculations determine how long a fully charged deep-cycle battery will last until it needs a full recharge. A quick basis for the calculation is as follows:
• E = C*V Avg
Where E is the energy stored in watt-hours, C is the capacity in amp-hours, and V Avg is the average voltage during discharge.
However, this is an oversimplification as the energy available depends on the rate of current draw. The higher the current the less energy you can take out of the battery. Imagine you can run 100 metres in 12 seconds, try keeping it up for 1 kilometer! The higher the power drawn the less energy available. We can provide you with the relevant guidelines to predict precisely how long your battery will last in your requirement.
Buying Cheaper Can be More Expensive in the Long Run! We often find that people try to save some money for their home inverters by buying locally manufactured or refurbished batteries used in conjunction with a branded inverter set.
This combination often doesn’t work well as locally bought batteries tend to be cheaper purely because they are of inferior quality. Buying a local inverter battery frequently ends up as a false economy, as the battery can damage the branded inverter set, lead to low power efficiency and even be a safety hazard. They may use inferior lead, substandard active materials, and the vendor may pass them off as similar to a branded battery and still charge almost the same price. If the internal wiring is poorly constructed, it may result in burnout or continuously blown fuses. Plus, regardless of craftsmanship, these batteries usually require extra maintenance and topping up more regularly.
The issue with reconditioned batteries is that there is no real way to know how good or bad a local battery is. You might be gambling with your money, or worse still, your safety. Our recommendation is to always make sure you buy new, brand-name batteries that have been quality tested to international industry standards and backed by a bona fide guarantee. Companies that strive for quality will also have an experienced customer service team that is there to help you with any questions about your battery quality and maintenance.
How do you maintain a deep-cycle AGM inverter battery?
By the very nature of their construction, deep-cycle AGM inverter batteries require far less maintenance than the flooded type of a lead-acid battery. AGM is an abbreviated term for ‘Absorbent Glass Mat’, which is a specially designed glass mat that acts as a sponge to absorb and immobilize the acid between the battery plates. The advantage of AGM batteries is that all the acid is completely absorbed into the mat, so there is no chance of electrolyte leakage. The other bonus is that this construction actually recombines the gas produced by water electrolysis when the battery is on charge.
For this reason, there is no requirement for topping-up and batteries are usually sealed units. If it is kept in a well-ventilated area, away from direct sunlight or other heat sources, and the terminals are checked for corrosion, it should give years of trouble-free use.
If the battery is of a sealed type, these are maintenance-free, whilst low maintenance batteries which are not sealed, need occasional topping up with water, according to the instructions supplied with the battery. Another consideration is that an inverter battery needs to be kept charged to minimize problems such as sulfation.
Sulfation is the forming of hard lead sulphate crystals in the plates of the battery. This hard sulphate is a symptom of low acid specific gravity due to undercharging the battery. In contrast, the formation of normal lead sulphate crystals is the standard product when battery plates are discharged. Unlike the hard variety in undercharged batteries, this sulphate is converted back into active material in the plate when the battery is recharged. Unfortunately, the high temperatures of tropical climates such as India and Africa tend to accelerate the deterioration processes but checking your batteries regularly can help mitigate or reduce the risks.
Best practice tips for maintaining your battery:
• Correctly and regularly charge an inverter battery according to the battery’s printed recommendations. Our customer service team is always happy to answer any questions you may have.
• Avoid under or overcharging the battery.
• Keep batteries well ventilated and out of sunlight.
• Avoid high-speed charging.
• Never operate a damaged battery.
• Remember that persistent under-charging speeds up sulfation and reduces an inverter battery’s life.
• Apply a ‘topping up’ charge only when needed.
• Keep each cell charged above 2.10 volts while in storage.
• Always store a battery only in a fully charged condition.
• Avoid charging when the battery is under load.
• Lower the threshold of charging by 3mV per cell per deg C when temperatures are over 25°C.
• Remember that it is normal that an inverter battery is warmer (but not very hot) at the end of a charge.
• Ensure the charger switches to ‘float’ charging when fully charged.
• Use good practices when Interrupting a charge. It is acceptable to do this if the correct procedures are followed.
How can I extend an inverter battery’s life?
An inverter battery needs to be correctly charged to ensure optimum performance. Undercharging shortens a batteries lifespan and overcharging diminishes the internal structure of the battery. It is imperative that you understand the correct voltage for your battery, and to build up a habit of charging via the manufacturer’s instructions at intervals advised by them. Most deep-cycle batteries need an amount of discharge and recharge cycles to perform at the peak of their operation. After approximately ten cycles they can be considered as ‘broken’ in. Deep-cycle batteries begin to decline after around one thousand cycles of charging. When the charge cycle pattern allows it, apply an occasional full charge.
We usually recommend around 14-16 hours on float charge every few weeks. When possible, store the batteries in well-ventilated, and moderate temperatures of no higher than 25℃ in areas out of direct sunlight. Cooler temperatures slow down the build-up of harmful parasitic reactions within the battery. Avoid deep discharges which take out more than 65% of capacity, and recharge as often as you can to avoid having low density electrolyte in the battery, which leads to damaging hard sulphate within the plates. Though larger branded inverter batteries are manufactured more consistently, each is unique in its ability to hold a charge.
More reputable battery manufacturers, such as the team here at Microtex, match the battery cells closely in age, impedance and state of charge to ensure stability in service and longer working life. We extensively test each battery to make sure it runs at its best capacity for as long as possible.
Tips for Saving Battery Power During Power Outages
Aside from the factors already mentioned, another way to extend an inverter battery’s life is to make sure it is being used correctly and only when needed. It should be standard practice to reduce a load on a battery while it’s performing the same functions as a mains supply. The less burden placed on a battery will mean the longer it will last until power is re-established.
Below are tips that should help in saving electricity while awaiting the switchover.
• Where possible, the first step is to switch off unnecessary electrical items.
• Look to replenishing all high output light fittings with low energy bulbs.
• Check battery terminals for corrosion. A certain amount of oxidation is normal, but heavy corrosion or white buildup of sulphates creates high resistance and will shorten the life of the battery and reduce the power being delivered to essential equipment and give less run time.
• Use the correct wiring capacity for each electrical product. Inefficient wiring increases the load on the battery by increasing the electrical resistance of the circuit and will reduce its lifespan.
• There is a term called ‘phantom power, which describes the power used by electronic devices while being plugged in. Switch off and unplug these items at least while awaiting the restoration of mains supply.
• If you have a water heater, reduce the temperature or switch off until power is returned.
• Switch off unnecessary lights, fans or other appliances if not needed.
Older appliances draw more power than new, more energy-efficient ones. Make sure that replacing them is given priority over items using less power.
In a world where there is an abundant choice of almost every product, a case needs to be made to enable a buyer to make the right decision. Being in the battery industry for 50 years has taught us a thing or two about the virtues of lead-acid batteries over newer technologies. The following is a list that we feel may help any prospective buyer in making an informed decision when it comes to deciding whether an inverter battery is a right choice for them:
• An inverter battery can be made in many capacities, ratings and sizes.
• Tubular flooded inverter batteries (the popular choice for inverters) need very little maintenance throughout their lifetime and are more robust than the AGM flat plate VRLA battery
• The TGel or Tubular Gel VRLA battery offers total maintenance-free operations Plus the advantages of a Tubular positive plate battery which can withstand deep cycling with long life.
• Lead-acid batteries still outperform newer chemistries regarding reliability and working capabilities.
• Lead-acid batteries are more ‘forgiving’ when overcharged or charged too fast or slowly.
• As long as they are charged once in 6 months, an inverter battery shelf life is superior to many other technologies.
• During test cycles, lead-acid batteries are still cheaper to run overall giving a lower total cost of ownership.
• Tubular Inverter batteries offer the best value for power and energy per kilowatt-hour.
• A lead-acid battery still offers the best life-cycle value.
• Around 99% of lead-acid battery components are recyclable.
• Once charged, an inverter batteries power loss is amongst the lowest in its category.
• Tubular flooded and TGel batteries can work in some of the harshest environments in the world.
Tubular flooded and TGel batteries are reliable and safe when used correctly. But that doesn’t mean that they should be plugged in and forgotten! Use our maintenance tips to keep your battery working properly and extend its lifespan. If you are ready to buy an inverter battery, our friendly customer service representatives will ask the correct questions to help you find the right size and energy output for your needs. Do you have any anecdotes and experiences of using tubular batteries that you would like to share? How long have your inverter batteries lasted? We’d like to hear from you!