F.A.Q

Information about inverters

Types of inverters

There are several different types of inverters available. The most common types are pure sine wave or modified sine wave. A pure sine wave inverter produces an output waveform that is the same as a domestic power outlet. They are more difficult to manufacture and are the more expensive type.

Power ratings

In addition to the output waveform, inverters also carry a power rating. This indicates the amount of power the inverter is capable of delivering. Most inverters will have a continuous rating and a surge or peak rating. The continuous rating indicates the power level it is capable of delivering under sustained use without overload. The surge or peak rating refers to a level that can be delivered for short periods. How long the inverter is capable of delivering its surge rated power output for will vary from one manufacturer to another.

Types of batteries

Not all batteries are created equal. They are manufactured differently for different purposes.

Automotive batteries

Modern car batteries are designed to supply a surge of high current to crank the engine of a car. This is achieved by manufacturing the battery with a large number of thin plates to maximise the surface area of the plates. The plates are composed of a lead "sponge", similar in appearance to a very fine foam sponge. If subjected to deep discharge, this sponge will quickly be consumed and fall to the bottom of the cells. Automotive batteries should never be discharged by more than about 30% before recharge. A car battery will only last about 30 deep cycles, while they may last for thousands of cycles in normal starting use (2-5% discharge). Automotive batteries are rated in Cold Cranking Amps (CCA). This is the amount of current that the battery is able to supply for 30 seconds at -20°C while maintaining a terminal voltage of a 7.2 volts or more.

Deep-cycle batteries

The major difference between a true deep cycle battery and other types of batteries is that the plates are solid lead.  They are manufactured with much thicker plates in each cell and can be discharged as much as 80% or more. Deep-cycle batteries are rated in amp-hours (AH): this means the current that can be drawn from the battery for a specified time, for example, a battery rated at 50 AH is able to supply 1 amp for 50 hours, or 2 amps for 25 hours and so on. This only works up to a point, as there are constraints on the maximum performance.

Note: There is no direct correlation between CCA and AH - one can not be calculated from the other

Marine batteries

Marine batteries are manufactured with thick plates in their cells to facilitate deeper discharges and are also rated in amp-hours. Most marine batteries are not true deep-cycle, but a type of hybrid. Most marine batteries may be safely discharged up to 60% before recharging.

Caution: Check with the battery manufacturer for recommendations of discharge rate. The information supplied should be used as a guide only.

Other types of batteries

AGM, or Absorbed Glass Mat

A newer type of sealed battery uses Absorbed Glass Mats, or AGM between the plates. This is a very fine fibre boron-silicate glass mat. These batteries have all the advantages of gelled batteries, but can take much more severe use. The plates in AGM batteries are tightly packed and rigidly mounted, and will withstand shock and vibration much better than any conventional battery.

AGM batteries have several advantages over both gelled and flooded batteries, at about the same cost as gelled batteries:

″ Since all the electrolyte is contained in the glass mats, they cannot spill, even if broken. This also  means that since they are non-hazardous, the shipping costs are lower. In addition, since there is  no liquid to freeze and expand, they are practically immune to freezing damage.

″ The charging voltages are the same as for any standard battery - there is no need for any special adjustments or problems with incompatible chargers.

″ AGM batteries have a very low self-discharge - from 1% to 3% per month is typical. This means that they can sit in storage for much longer periods without charging. 

Gelled electrolyte

Gelled batteries, or gel cells contain acid that has been "gelled" by the addition of silica gel, turning the acid into a solid mass that looks like thick jelly. The advantage of these batteries is that it is impossible to spill acid even if the battery is broken.  A disadvantage of gel cells is that they must be charged at a lower voltage than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death.

Battery Maintenance

Lead-acid batteries are perishable. During the discharge process, soft lead sulphate crystals are formed in the pores  and on the surfaces of the positive and negative plates inside the battery. This creation of hard crystals is commonly called lead sulphation and it accounts for over 80% of deep-cycle battery failures. The longer sulphation occurs, the larger and harder the lead sulphate crystals become. The positive plates will be light brown and the negative plates will be a dull, off-white colour. These crystals lessen a battery's capacity and its ability to be recharged. Recharge as soon after discharge as possible, and if the battery is to be stored for more than two weeks, top up the charge frequently. This is the best way to prevent sulphation.

 

1. Add a battery conditioner in accordance with the manufacturer's instructions. This is a chemical additive, which prolongs battery life.
    
   
2. Alternatively use a "BATMAX" Ô Battery Maximiser. This simply attaches to your battery and removes lead Sulphate build-up and extends the life of your battery.
    
   
3. Check electrolyte levels regularly and top up only with demineralised water as required.
    
   
4. Buy a hydrometer and check the specific gravity of the electrolyte in each cell of the battery. This will detect damaged or collapsed cells before they leave you stranded with a useless battery.
   

Storing a battery

 

1. If the battery has filler caps, check the electrolyte level in each cell. If required, add only Demineralised water to the recommended level, but do not overfill.
    
   
2. Clean the top of the battery and the terminal posts.
    
   
3. Fully charge the battery.
    
   
4. Store it in a dry, cool place (above freezing), where it can be easily recharged.
    
   
5. Most importantly, prevent sulphation by keeping the battery charged at 100% state-of-charge level By frequent recharging. Once every two weeks is recommended.
    
   
6. Use a "BATMAX" Ô battery maximiser.
   

Caution: Always check with the battery manufacturer for charging instructions. Damage to the cells or reduction in service life may result from incorrect charging.

Precautions when working with Batteries

 

1. If battery acid contacts your skin &/or clothing wash immediately with soap and water.  If acid enters the eye, immediately flood eye with running cold water for at least 20 minutes and get medical attention immediately.
    
   
2. Never smoke or allow a spark or flame in vicinity of battery or engine.
    
   
3. Do not drop a metal tool on the battery.  The resulting spark or short-circuit on the battery or other electrical part may cause an explosion. 
   

Important Safety Instructions for Inverters

General Safety Precautions

 

1. Do not expose the Inverter to Rain, snow, spray or excessive dusty conditions.  To reduce the risk of hazard, do not cover or obstruct the ventilation openings. Do not install the Inverter in a zero-clearance compartment as overheating may occur.
    
   
2. Inverters contain components which can produce arcs or sparks.  To prevent fire or explosion do Not install in compartments containing batteries or flammable materials or in locations which require ignition-protected equipment.  This includes any space containing gasoline-powered machinery, fuel tanks, or joints, fittings, or other connection between components of the fuel system.
    
   
3. Ensure the existing wiring is in good electrical condition, and that the wire size is not undersized. 
   

Inverter Cable & Accessories Guide

12 Volt to 240 Volt Inverter

Installation Guide for Inverters

 

  Battery Size Guide

It is important to match the battery size according to the power rating of the inverter.  Therefore to ensure peak performance, it is important to choose the correct Battery for your inverter.

The battery size will depend on the load and intended running time.  The formula below is a guide to choosing the correct battery size;

Recommended Battery size = Inverter rating in watts ¸ input voltage x 10

  e.g.     1700 Watt Inverter ¸12Vdc x 10 = 1400 Amp Hours  

Minimum Battery Size = Inverter Rating in watts ¸ input voltage x 3

  e.g.     1700 Watt Inverter ¸12Vdc x 10 = 425 Amp Hours  

For quick reference on the MINIMUM BATTERY SIZE  please refer to table below:

Microwave Ovens

The advertised rating of a microwave oven normally refers to the cooking power being delivered to the food and not the operating power of the microwave e.g. a microwave oven advertised with a 600 Watt rating would run at approximately 1100 Watts.  To find out the power consumed by your microwave, check the compliance plate on the rear of the microwave or consult your owner's manual.  Also, some microwaves may NOT run from a Modified Sine Wave inverter and may require a True Sine Wave.

Connection of the Inverter to the Battery

 

1. Always ensure the Inverter is switched OFF before connecting to the DC supply.
    
   
2. Ensure you connect the Inverter directly to your Battery Terminals, Positive (+) DC (Red) cable to the positive (+) terminal & the Negative (-) DC (Black) cable to the negative (-) terminal. Ensure connections are firm for best performance.  Loose connections and incorrect sized DC cables can result in severe decrease in voltage, which may cause damage to the component or product you may wish to operate. Do NOT connect the negative (-) lead to the vehicle chassis.
    
   
3. For best performance, the unit should be placed as close as possible, but not directly on top of  the battery supply.  DC Cables should not be extended.
    
   
4. The Inverter is designed to operate on a battery supply only.
    
   
5. For Inverters 600 watts and above it is recommended the use of a circuit breaker or fuse in the positive lead of the inverter mounted as close to the battery as possible.
    
   
6. DO NOT reverse the polarity, i.e DO NOT put the positive (+) leads and negative (-) leads on the wrong Battery terminals. Damage resulting from this is not covered under warranty.
    
   
7. Once the inverter is connected to your battery you are ready to operate your inverter.
   

Safe Operation of Inverter

 

1. To operate the Power Inverter, turn the main switch ON. The power inverter is now ready to deliver AC power to your appliances.  If there are several appliances, turn them on separately after the inverter has been turned on.
    
   
2. Never connect your inverter directly to a 240 Volt source, (either on purpose or accidentally), as 240 volt feed-back into the front of the inverter will DO DAMAGE and is not covered by Warranty.
    
   
3. DO NOT attempt to run a welder, air conditioner, or air compressor off of your power inverter. These items have a huge surge rating and will overload your inverter.
    
   
4. You CANNOT run a battery charger from your inverter to the same battery bank the Inverter is connected too.  This generates a loop sequence that only discharges your batteries quicker that the charger can recover them. This is due to the losses and inefficiencies within the inverter and battery charger.
    
   
5. REMEMBERthat this product produces 240Volt AC electricity. Handle with caution and keep out of reach of children.
    
   
6. DO NOT attempt to operate an appliance that exceeds the rated output of the inverter. Your Power Inverter is protected against accidental overload however constant overload will void your warranty.  If you are using the inverter continually near its peak capacity you should look at purchasing a bigger size Inverter. You should not continually make the inverter work at maximum output.
   

Maintenance

Very little maintenance is required to keep the inverter operating properly.  The exterior of the Inverter should be periodically cleaned with a damp cloth to prevent accumulation of dust and dirt.  At the same time tighten the screws on the DC input terminals.

Warranty

We warrant this product against defects in materials and workmanship for a period of 12 months from the date of purchase and will repair or replace any defective Power Inverter when directly returned, postage paid, to us. 

Warranty return address :  

  INVERTECH AUSTRALIA

  21 Tarnkun Street

  ALEXANDRA HEADLAND  QLD   4572

  Ph 07 5479 2188    Fx 07 5479 3188 

  (Postal – PO Box 1056, Mooloolaba  QLD 4557)

This Warranty will be considered void if the unit has suffered any obvious physical damage or alteration either internally or externally and does not cover damage arising from improper use such as; plugging the unit into unsuitable power sources; attempts to operate products with excessive power consumption requirements; or use in unsuitable environments.

The replacement of any part or labour involved will not have the effect of extending the warranty period of the Inverter.

Inverter Summary

One thing you will find in the marketplace is substantial price differences from one inverter to another, not only between modified and true sine wave but also between different brands.  Due to the market for such items becoming more competitive, there is a growing demand for a large number of products entering the market that are made for the lowest possible price, with no regard to overall reliability or actual performance.

When shopping around for an inverter ask yourself if you want a cheap inverter that, over time may end up costing you more money and maybe cause damage to your equipment. A good quality unit may cost you more initially but it will provide you with many years of reliability.