New Technology Rechargeable Batteries versus Single Use batteries

(non technical article)

-versus- ?

Rechargeable batteries have been around since the 1960s and have improved considerably since the early days. Rechargeables potentially save lots of money. The newer rechargeables power digital cameras for longer than alkaline batteries. Recently a new battery technology has been developed by Uniross (called Hybrio) and Sanyo (called eneloop). Here are the advantages and disadvantages of each of the three technologies.

Single Use Battery

• Use immediately “off the shelf”
• Lasts a long time when not used
• Relatively cheap to buy 
• Does not require a charger
• Voltage drops gradually, leading to dimmer torches, crackly radios etc
• Need to throw away when flat (not environmentally friendly)
• Economical for clocks and remote controls, where battery changed infrequently
• Cheaper batteries can leak and destroy equipment
  

Standard Nickel Metal Hydride Rechargeable Batteries

• Needs to be charged on first use
• Runs down in a few months when not in use (self discharge)
• More expensive than single use batteries
• A charger is required
• Voltage remains high throughout charge - leading to extended use
• Can be recharged and re-used 500-1000 times over a period of many years
• Not economical or practical for clocks and remote controls
• Does not leak
• Less waste - more environmentally friendly
  

Low discharge rechargeable batteries

• Use immediately “off the shelf”
• Lasts a long time when not used
• Similar in price to standard rechargeable batteries
  
• A charger is required to recharge, but not for first use
  
• Voltage remains high throughout charge - leading to extended use
  
• Can be recharged 500-1000 times over a period of many years
• May be economical and is practical in clocks and remote controls
  
• Does not leak
• Less waste - more environmentally friendly 
  

Cost Savings

These calculations are based upon the fact that a pack of 4 x AA costs £3.00, and a pack of AA rechargeables around £10, with the cost of recharging a set of 4 batteries about 1p per charge. For low usage appliances, there is little or no saving, or it may be even dearer to use rechargeable batteries. For example an LCD quartz clock may go for several years on 1 x AA battery. However if you take a frequently used digital camera with 4 AA batteries that are charged twice a week, the saving is around £300 a year. That's a saving of £1500 for a 5 year period on just one appliance! Most household items would fall between these two extremes, but other examples of heavy usage devices are hand held GPS receivers, personal MP3 players, baby monitors and most kids' toys. Medium use items could be LED torches, electric razors, cordless mouse and keyboard.

Care of Rechargeable Batteries

Keep them in a safe place, preferably cool, try not do drop or dent them. Remember some way of knowing whether or not the batteries are charged or discharged. For example if you use a storage case for them, you can place the batteries tips IN to show they are IN Charge, tips OUT to show they are OUT of charge. Try to charge batteries up which are in a similar state of discharge. This prevents individual batteries from getting hot. Modern batteries can cope with this, however it does put them under extra stress and may reduce their life slightly. Having said that, the latest and more expensive chargers measure the charge in each individual batteries, and only give them as much charge as they need.

Steve Nicholls
Powercenta, 2006