What Inverter Users Must Know About Inverter Batteries

Inverter batteries are critical to the performance of an inverter power system. An inverter must run on at least one battery, because the power used by the inverter to supply your power requirement is drawn from a battery or set of batteries. The primary job of an inverter is to convert the direct current (DC) stored in the inverter battery, to alternating current (AC) used to power electrical appliances.

Inverter Battery Bank

So, we speak of an inverter's battery bank. The concept should be clear. Power is stored (banked) in an inverter's battery bank in the state a battery is designed to store (DC power) and that is what the inverter converts and provides in a form equipment can use (AC power), when there is no mains supply. An inverter with a built-in charge performs the additional role of charging those batteries when there is mains supply. If an inverter has no inbuilt charger, the user will need a separate charging system.

The battery bank an inverter needs will depend on the capacity of the inverter. This is also related to the load capacity intended for the inverter, including the expected backup duration to carry that load. Battery bank size will vary from one battery to a very large number of batteries. A 15KVA Sukam Inverter, for instance, is designed to run on a battery bank of 30 units, each 200AH 12V batteries. On the other hand, the Sukam 800VA inverter uses only 1unit of the 200AH 12V battery.

Cost of Battery Bank Component

Now, it should be obvious that the performance of your inverter's battery bank is at the heart of the performance of your inverter setup. Not that the inverter's role is diminished, but the point is being made that the battery performance is also critical. To accentuate the importance of the battery component, it has to be noted that the battery bank is, in most cases, the major chunk of the expenditure on an inverter setup. Good quality batteries are relatively expensive and tend to shoot up the cost of the project.

Battery Sense

Where does that leave you? It is that you must carefully consider issues relating to the battery investment. Here are some key points:

• Since it will cost quite some money, it's important to ensure you get good quality that matches your expenditure. Plain value-for-money principle. So, be sure of your source and that the quality you get is what you paid for.
• When you can't afford the deep cycle sealed maintenance-free battery, ideally recommended for your inverter, you can still consider the option of wet cell batteries. They cost far less, can serve you reasonably, though you must realise that they are more challenging to manage. Besides, if they are not deep cycle, they are not designed for deep discharge, which may affect their durability. Good quality wet cell batteries have, however, given satisfactory performance in use.
• Your inverter quality may substantially determine the fate of your batteries. The battery plates may be affected by the quality of voltage the battery receives. Damage that could shorten the life of your batteries could result from unregulated charging voltage coming from the inverter's charging system. Good inverter brands may protect against such damage. Sukam, for instance, boast of it’s battery protection mechanism, based on its CCCV (constant current constant voltage) charging system. That ensures regulated voltage to protect the battery plates, extend battery life and give optimal delivery. It uses silicon controlled rectifier technology, believed to be the best for battery chargers, to achieve constant charging and minimum power consumption. Fuzzy Logic Control or FLC technology protects the batteries by controlling the charging current of the battery to an optimum level which extends battery life and achieves reduced power consumption.
  
  A good quality inverter should also have a low battery/deep discharge protection to prevent low discharge that can damage the battery bank. Having your battery discharge to very low levels or virtually completely could easily ruin them. You could manually monitor the battery level, but that could become an engaging chore. A good inverter product will provide inbuilt protection. Let's use the Sukam example again. Sukam, first, has LCD display of inverter performance status. Part of the alternating displays is battery charge level information. So, you can see your battery level at a glance, anytime. That way, you know when it's getting low, without guesswork. That's not all. The Sukam inverter will give an alarm if the battery gets to its low charge indication point. So, it warns you to reduce your load (and extend use time on remaining battery charge) or, better still, power down the system. That message is clearly displayed on its LCD message panel. Your Sukam inverter has the additional protection of being able to shut itself off, if you fail to heed its low battery alert. The moment the battery is down to a potentially harmful level, the inverter shuts itself off. That shut-off doesn't just happen. It is preceded by an extended alarm that alerts you that the system is about to go off, so you get a brief moment to save a PC job, for instance. Intelligent design, really.
  
  Battery overcharge is also as damaging, meaning that the inverter you buy should have inbuilt over-charge protection. Battery overcharge corrodes battery plates, shortening the life span of the batteries.
  
  Given that the battery system of your inverter is going to be a substantial part of the cost and that you naturally won't find frequent battery replacement any bit funny, it's as important to buy good quality batteries as it is to buy an inverter brand that has proven design mechanisms to protect the battery bank. That's an important point to note.
  

Starting, Deep Cycle, Dry & Wet Cell and all that

You must have heard these and more terms relating to batteries, in particular, with reference to inverters. What do they really mean and how does that affect your choice of battery type?

Batteries are mainly used in automotive, marine, and deep-cycle applications. Automotive use batteries are starting batteries which provide a large jolt of starting current to start an engine. That may take up to 5% discharge, for that limited time the battery fires the engine up. While the engine runs, they have a limited role. They are not designed for deep discharge.

Deep cycle batteries, in contrast, are designed for deep discharge. They can routinely be discharged to as much as 80%. What that simply means is that the battery can drain, while in use, to as low as 20% charge, and get recharged again, repeatedly. That may harm a starting battery over several discharges, but the construction of a deep cycle battery enables it withstand such deep discharge over many cycles. That is why they are the ideal battery for power systems like inverters and solar power systems. While starting batteries will work in such use, they will offer less durability, other factors being equal.

That a battery is the so-called "dry cell" or "wet cell" is not synonymous with whether it is deep cycle or otherwise. Flooded batteries or wet cell batteries are easily those with removable caps and electrolyte that dries up with time. The user is supposed to check occasionally to ensure that the cells have not gone dry. They require "topping" or the cells may be damaged if they dry up. What you may not realise is that the sealed, maintenance-free batteries are also flooded.

A big problem with batteries is in being sure of what you are really buying. You probably just have to trust the vendor, unless you have a deep knowledge of battery technology. The durability of your batteries amy also depend on you, as it is easy to get them damaged. A large dose of overcharge can quickly damage the battery. Dried up battery cells could spell the death of your battery. Being careful with your batteries could save you untimely replacement of batteries.

If you take to heart the importance of the battery support for your inverter, you will possibly make a better judgment of what to buy and how to handle it. That could save you lots of money.

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• What Inverter Users Must Know About Inverter Batteries