Battery & charger reviews
TipsMethodologyReviewsBest BuysUpdatesContact

  RRS Feed

Introduction

This site reviews consumer style battery chargers which retail for around or below AUD$150.00. It tests various rechargeable batteries and seeks to provide some practical guidance to end users about which battery types and brands are best suited for their needs.

You might ask yourself why supermarkets do not stock many rechargeable batteries. The answer is simple; just look at all the other non-rechargeable batteries they sell. They are not about to undermine this lucrative business by selling rechargeable batteries. You may also notice that the big name battery companies offer a limited selection of rechargeable batteries.

Charger categories

There are two broad types of chargers reviewed, Universal chargers and Mini chargers. Universal chargers can charge several batteries sizes including AAA, AA, C, D and 9V and different battery types such as Recharge Alkaline Manganese (RAM), Nickel Cadmium (Ni-Cd) and Nickel Metal Hydride (Ni-MH). Mini chargers are smaller, have less features and safeguards. They can generally only charge 2 or 4 AAA or AA batteries. Universal chargers are usually larger, offer more features, have greater functionality and are usually more expensive than Mini chargers.

Which category of charger is best for you depends on your needs. Universal charges are suitable for people:

  • with children (and their battery powered toys);
  • who have plenty of battery powered big boys toys;
  • who use more powerful C, D or 9V batteries; or
  • you require more functionality and flexibility than that offered by a Mini charger.

Mini chargers are more appropriate where:

  • you only use AAA or AA batteries;
  • you need faster charging of batteries;
  • you need it for a single purpose, such as digital camera batteries or a remote; or
  • compactness and portability are a must.

How do chargers work?

There are three broad ways in which a charger operates. The Chargers are Manual (ie user controlled), Integrated Circuit controlled (IC) and Microprocessor controlled. Microprocessor controlled chargers invariable offer more functionality and safety features. If you can afford the extra dollars, buy a smart charger. The term smart charger normally means a charger that is controlled by an Integrated Circuit controller (IC) or a Microprocessor.

You also hear chargers being described as Slow, Rapid, Fast and Ultra Fast, these terms are can be meaningless and the Doc avoids their use. They are meaningless since a AA size battery rated at 400 mAh will take a far shorter time to charge than one rated at 2200 mAh. But this is a reflection of the capacity of the battery, not the charger. In broad terms slow chargers are controlled manually and fast and ultra fast by Integrated Circuit or Microprocessor.

Battery types

Batteries are either Primary or Secondary cells. A Primary cell battery is one where you use it once and then throw it away. Secondary batteries are designed to be recharged. While it is often said that Primary cells cannot be recharged, that is not factually correct. Primary alkaline batteries can be recharged up to 15 times. Most consumer style chargers do not have that capability, except the Rezap charger.

This site mainly looks at Recharge Alkaline Manganese (RAM), Nickel Cadmium (Ni-Cd) and Nickel Metal Hydride (Ni-MH) batteries – Secondary cell types. The normal voltage of AA or AAA sized batteries is either 1.5 (Primary cell) or 1.2 (Secondary cell) volts.

The most common battery types around the house are AAA, AA, C, D and 9 volt. Accordingly, we look at these battery sizes and their chargers. As AAA and AA seem to be the most popular sizes there is a bias towards them in tests.

Chargers and their batteries

Chargers cannot be looked at in isolation from batteries or the proposed use of the batteries. The Table below compares some of the strengths and weaknesses of Recharge Alkaline Manganese (RAM), Nickel Cadmium (Ni-Cd) and Nickel Metal Hydride (Ni-MH) batteries. Select the best battery type suitable for your purpose.
 

Battery Type

Strengths

Weaknesses

Rechargeable Alkaline

  1. Suitable for low drain devices over long periods.
  2. Readily available in most supermarkets.
  3. No or minimum memory effect.
  4. No need to charge before first use.
  1. Limited number of recharges.
  2. Higher cost option due to small number of recharges.

Ni-Cd (Nickel Cadmium)

  1. Reasonable mix of drain verse battery life.
  2. More tolerant to abuse such as overcharging or high rates of discharge than Ni-MH.
  3. Large number of recharges, but less than Ni-MH.
  4. Better for use in high torque devices like power tools.

  1. Cadmium is highly toxic.
  2. Has a memory effect. So if you do not fully drain a Ni-Cd battery, subsequent recharges will result in shorter battery life.
  3. Battery must be discharged before recharging.
  4. Must be charged before first use.

Ni-MH (Nickel Metal-Hydride)

  1. Suitable for high drain devices over a short period.
  2. Good for use in heavy drain devices.
  3. Large number of recharges, so cheaper over long term.
  4. Minimum memory effect.
  5. No need to discharge battery before charging.
  6. More powerful than Ni-Cd and Alkaline batteries.
  1. Higher rate of self discharge than Ni-Cd and RAM.
  2. Must be charged before first use.
  3. Less tolerant to abuse such as overcharging or high rates of discharge than Ni-Cd.

For most homes, The Doc does not see any compelling reasons to use Ni-Cd batteries if Ni-MH are available, as Ni-MH are superior in most respects. Ni-Cd are still preferable for harsher working environments or when used in high torque devices like drills. If you need a battery to hold a charge longer than 2-3 months, you need to go alkaline, either Primary cell or Secondary cell. If you do not need extended life than Ni-MH batteries are the current best all round rechargeable battery for the money. This graph compares the performance of a Grandcell RAM, Arlec Ni-Cd with two Ni-MH battery sets (just hit the refresh button if the graph does not display correctly the first time). For high drain devices the Ni-MH's have the clear advantage.

Modern rechargeable batteries are not like their predecessors of several years ago. The new rechargeable are modestly priced, powerful and can be recharged up to 1,000 times. This is particularly true of Ni-MH batteries in high drain devices like digital cameras.

How many recharges will I get from a set of rechargeable batteries?

The honest answer is that it depends. It depends on:

  1. the quality of the batteries. The Doc knows of an Australian distributor that ran tests on Ni-MH batteries. The Chinese brand batteries lasted about 300 charges, the Sanyos lasted over 900 charges. A Canadian company charged a set of Ni-Cd batteries over 2,300 times and they were still in good working condition! For consumer batteries, the quality ranking is broadly: Japanese>Tawianese>Chinese.
  2. the quality of the battery charger used. Here is where extra safety features on a charger pays for itself, especially those that protect from overcharging.
  3. the ambient air temperature and battery temperature during charging and use. The idea temperature is between 18-25 degrees Celsius.
  4. whether you deplete the batteries below 0.9 volts.

To maximise the number of recharges look at the Doc's Tips, especially on good charging technique.

Devices that can use rechargeables

Devices where rechargeable batteries can be more cost effective include:

  • Digital cameras;
  • Camera compact flash units;
  • Portable CD players;
  • MP3 players;
  • Mini disk players;
  • Portable radios;
  • Gameboys;
  • PDAs;
  • Palmtops;
  • Microcassette Recorders;
  • Home theatre remote controls that are backlit;
  • Most children toys;
  • Remote control planes and cars;
  • Torches (flashlight) – when used often.

Having trouble working out which type of rechargeable battery is best suited for your particular device? Have a look at the Table above.

Devices where Primary cell still offer good battery life and value for money, include:

  • Wall Clocks;
  • Calculators;
  • Smoke detectors;
  • Torches (flashlight) – when used infrequently.

Do not use rechargeable batteries where a long shelf life is required, eg smoke detectors, wall clocks, etc.

Assumptions: The Doc is talking about consumer style devices that take standard AAA, AA, C, D or 9V batteries. And any device that is not designed for use for a specific battery chemistry.

Be green and mean

Pause for a moment and think. One set of rechargeable batteries against hundreds of primary cell batteries means scarce resources are saved in manufacture, and landfills are not filled with tonnes of throwaway batteries.

Being fiscally mean is another advantage of rechargeable batteries (Ebenezer Scrooge would be proud of you). Some customers have the wrong approach though. They seem to think that cheap is always better. This is not the case with either chargers or rechargeable batteries. A decent charger with added safety features may cost another $20-30 to buy, but that is repaid many times over by maximising battery life. A good quality battery only costs a small amount more, but will deliver power longer for a given charge and also maximise the number of recharges.

It is preferable to look how much you are saving by not buying Primary cells every other week. Let us take a conservative example. A children’s toy uses 4 AA batteries. Junior is allowed to use a high drain toy as much they want over 2 years. Assume the toy will go through 200 sets of batteries. Lets do the calculations: Duracell Ultra at $7.99 per pack for a set of 4 (Nov. 2003). The total cost is $1,598.00 (pass Mum the smelling salts). But most parents are likely to be rationing junior’s use of the toy before that figure is reached! But Mum, the Doc bets you it is harder to ration the batteries for the Big boy's toys.

A Rezap battery charger costs $86.00. Sanyo 2100 mAh Ni-MH batteries, are $30 for a set of 4. Both these figures include delivery costs. Allow 5 cents per recharge for the electricity you use (which is an exaggeration) giving a grand total of $126. No rationing needed here. Now you see why the Doc is adamant about getting a decent charger and battery set. So you can be both green and mean.

 

 

[Tips][Methodology][Reviews][Best Buys][Updates][Contact]

Copyright(c) 2003-2008 Michael G Hains
thedoc@internode.on.net