Inverter Guide - How to Choose a Dependable Inverter

Finally, you have decided you need an inverter because your calculations have shown the inverter power system as a more cost-efficient option. So, which inverter do you go for?

Choosing an inverter is a tough decision because of the significant cost of inverters. Even the low-capacity inverter is a sizable chunk of money off one's pocket. The investment must therefore be justified by the performance of the inverter. That's the challenge: selecting a tough-performing inverter without knowing much about inverters could prove daunting. That's what this guide is aimed at helping you with.

Define Your Critical Needs

What do you want to power with an inverter? For the home, most people would love to power every appliance and device they have: plasma TV, DVD, light points including external security lights, kitchen appliances, refrigerator, freezer, several air conditioners, water dispenser, water heater and you name it. The good news is that inverters can do all that. The bad news: you need a large capacity inverter to take all that load. That translates to a huge battery bank. And that means some good money, because batteries today are rather expensive. A sealed maintenance-free dry cell 200AH 12V battery currently goes for about N50,000 or more, depending on the brand. For a battery bank of 10 units, which a 7.5KVA Sukam inverter requires, that's already N500,000 or more. Even the cheaper wet cell battery type will cost close to N30,000 each.

That could prove prohibitive and a stumbling block to owning an inverter and deriving its acclaimed benefits. A smart approach is to scale down to essentials. What are your most important needs to power with the inverter. You can use fans in place of air conditioners, for instance. You can use energy-saving bulbs in place of the regular tubes you have. You can run your freezer when there is public supply but keep it off the inverter. Simply put, with pragmatic selection, you can trim to an inverter capacity you can afford. With such careful evaluation, most homes can scale down to a 1.4KVA or, at most, 2.5KVA inverter. That applies to small offices, too. Configure to your most basic and critical needs so you can begin to enjoy the enormous value inverters offer.

Determining Your requirement

This chart is a quick guide to load capacity of some inverter sizes, based on the Sukam brand. It helps you estimate your need, though just a rough guide.


If you are happy with calculations and want a more precise computation, you can. Here's how:

• First list out the appliances that scale through your screening exercise.
• List the wattage of each item. Wattage is the amount of electricity each item requires to function. For items like bulbs, it's clearly written on the body. To help you with other items, see this chart of common wattage of appliances.
• Calculate the total wattage of all items, which gives your total running requirement, if all devices are on at the same time. That's your load.
• Now, you need to calculate your backup requirement. That will be given by the total load multiplied by required backup time. You need 10 hours backup? Multiply by 10. Example: total wattage of all items is 600watts and required backup time is 10 hours. That gives total requirement of 6,000W.
• That is the true power requirement. Because of the dissipation that results from the power factor, the apparent power, as stated in VA (volt-amps), is usually higher. If you apply a power factor of 0.90 (true power ratio), 6,000 watts is given by about 6,700VA. That's a rough idea of your battery requirement, but because the expected discharge of the battery is roughly 80%, you will be needing some 8,500VA (6,700/.8) of battery power.
• Now, divide that total requirement by the rated capacity of the battery to know the number of batteries for the system you need. With 200AH 12V batteries, that rating is 2400. For 8,500VA power requirement, that's 3.5 ( or 4) batteries.
• That's what the unit should be designed to be powered by for you to have the power you need.

What Brand of Inverter?

Having decided on capacity, you have to get down to choosing an inverter brand to buy. Some of the names available in the Nigerian market today include Sukam, MoPower, Genius, Luminous, etc. This guide isn't going to recommend one to you, but we'll spell out some criteria you should give attention to, to be happy with the end-result. So here:

• Track Record: Can you identify any users of the inverter brand and do they have a good story to tell about its performance? Find some proof that this product has measured up in use.
• Technical Support: Every equipment, let alone an electrical device, can suffer damage in use. Support for the inverter you want to invest in is critical. If you have any problem with the equipment, is the technical capacity locally available to handle it? What about the spares? It won't help to buy an inverter that won't be effectively supported.
• Warranty: One assurance you receive about quality is from how willing the manufacturer/dealer is to back up their product with an effective warranty. Do they have any on an inverter brand you're considering? What's the duration of the warranty? The longer, the better for you.
• Reputation of Dealer: Warranty on the inverter will only make meaning when you deal with a reputable organisation that has integrity. It's in your interest to buy a product from a dealer that you are comfortable about their standing.
• Customer Care: You also want to be sure that you are buying from a company that cares and one that will have the listening ear if you have issues. You expect some courtesy and it's easy to know if it's there, right at the outset. Buying an inverter is a long term investment and you want your supplier to respond if you need help.
• Pure Sine Wave or Modified Sine Wave?: Whether you buy a pure sine wave inverter or modified sine wave inverter or something else, will depend on you pocket and how much you wish to spend. Pure sine wave inverters provide the best quality of current, but are more expensive. When choosing, you should, at least, know what you want and ask for it.
• In-built Charging System?: Your inverter will convert DC power in your batteries to AC to power your equipment. But the batteries need to be charged and that requires a charger, which may still cost you some money. That, though, is if you buy an inverter without a built-in charging mechanism. You should consider buying an inverter that can charge your batteries as well.
• Automation & Digital Display: Is the inverter fully automatic, requiring no manual intervention in its operation? That's what you want, isn't it?. Besides, there are inverters that provide continous digital display on an LCD panel, showing the running status. For instance, what the battery bank level is or what total load is. Such information can help you in managing the equipment.
• Battery Protection: The battery bank is a significant part of the cost of inverter set-up. Protecting your batteries is very important. If the inverter you buy is high-tech, it will have in-built mechanism for protecting the batteries from deep discharge. A Sukam inverter, for instance, will give an alarm and display a message to reduce load or shut the system down, when your battery has discharged to a low level. That helps prevent total discharge that can ruin the batteries. When you ignore that alarm from a Sukam inverter, it also has an in-built mechanism to shut itself down if the battery level is getting to a potentially damaging level. The inverter you buy should have such features unless you want to keep investing in batteries.
• Price: Probably, you would have like this put first. You certainly want to bother about the price, but, most of all, you want to be sure you get value for the price you pay. If you buy cheaply but it turns out a disaster, that's money completely lost. Good quality products naturally cost more, but be sure you get a fair price.

So, there it goes. If you want an inverter now, you at least have a basis for your selection.

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