Some common sense Tips on how to use and care for batteries.

• Read and follow the instructions with your batteries.
• Use the correct charger for your battery type.
• Use a good quality battery charger.
• Use a smart charger (i.e. microprocessor or IC controlled) for rapid recharges, as they will cut off the power and not overcharge the battery. Overcharging also causes voltage depression (sometimes mistaken for memory effect) and will shorten battery life.
• Do protect batteries for high temperatures during charging and storage. It is best to charge batteries between 18-25 degrees Celsius.
• Once charged, allow the batteries to return to room temperature before using them in a device.
• Store batteries in a charged state, 40% for Ni-MH and 100% for Ni-Cd.
• Store batteries in plastic containers for better battery management, like these.
• Remove batteries from a device if it is not going to be used for an extended period (eg over a month).
• Do not completely discharge the battery, drain only to 0.9 volts.
• Do not overcharge the batteries; you will dramatically shorten battery life.
• Do not leave batteries on a trickle charge for extended periods, say over 48 hours as it can change battery chemistry and damage the battery (however, remove alkaline batteries after charging is complete).
• Do not use batteries of the same size but different capacity in a device. For example, 4 AA batteries, where 3 are rated 2100 mAh and the fourth 1850 mAh. The 3 larger capacity batteries will continue to give power after the fourth is flat and the fourth can be damaged.
• Do not mix old and new battery sets. Try and keep batteries in a set where they are charged and used as a set, it will extend their effective life. The Doc numbers his sets which assists in keeping them together.
• Do not carry batteries in your pocket with keys and coins, as they may short circuit causing extreme heat, leakage or in the worst case an explosion.
• Do not store batteries in metal containers they may short. It is best to store then in plastic battery holders.
• If a battery is leaking, put on disposable gloves, remove the battery, clean up any spillage. Then dispose of the gloves and the faulty battery. Ni-Cd batteries are especially toxic, but it is prudent to use these precautions for all battery leakages.

Common ways rechargeable batteries are damaged

Most damage does not occur through use, but during the charging process. Common causes are:

• Overcharging the batteries.
• The charger overheats the batteries during charging.
• The user fails to exercise sufficient care during the charging process, especially when using a manually operated charger.
• Using the incorrect charger for the battery type. Particular care must be exercised with alkaline batteries (Primary & Secondary cells).
• Completing draining a battery. A battery is usually considered flat when it reaches 0.9 of a volt. The normal voltage for a AA or AAA battery is either 1.5 volts (for a Primary cell) or 1.2 volts (for a Secondary cell). Some electronic devices will sense the battery is flat when this voltage is reached and will no longer operate. Others, like torches, clocks and radios will completely drain the battery. Tip: Provided you have not induced reverse polarity you maybe able to recover the battery. Put the Secondary cell in a manual charger for 30 to 60 minutes, and then transfer to a charger with safety features to detect defective batteries. You may not be able to start with a “smart” charger because it will reject the batteries due to no charge. But if you give the batteries a quick charge in the manual charger the smart charger can takeover, but reject batteries that are truly defective. If the battery starts to get hot in the manual charger, stop the charger and throw out the battery. Warning: this technique only applies to Secondary cells, not Primary cells.

It is for this reason that we award better ratings to chargers that offer protection against these risks. The more idiot proof a charger is the better! Yes we have damaged batteries during charging if you are wondering.

Battery myths

• You can only use a particular brand of battery with a particular charger. A good universal charger like the Rezap Battery Doctor or Vanson Speedy Box can safely charge most battery brands of a compatible battery type. Although more care needs to be exercised in charger selection with alkaline batteries. Warning: do not try and charge a RAM battery in a charger that is designed to charge Ni-Cd or Ni-MH. Or charge a Ni-MH battery in a Ni-Cd only charger.
• Rechargeable batteries cannot be used in toys or other electronic products. If a toy can operate on carbon zinc or alkaline batteries, it can in most cases run on RAM, Ni-Cd or Ni-MH. Just ensure you use the correct size.
• Rechargeable batteries are 1.2 volts and my device says you can only use 1.5 volt batteries. Carbon zinc and alkaline batteries are commonly rated at 1.5 volts. Whereas rechargeable batteries are rated at 1.2 volts. It is not the maximum voltage so much as the operating voltage that is important here. For example, applying a load of 5 ohms to a set of 4 AA alkaline batteries, the dominant operating voltage is between 3.5 and 4.5 volts, whereas with a set of 4 AA Ni-MH batteries the dominant operating voltage is between 4 and 4.5 volts. This is clearly illustrated in the following graph: