FAQ's

Is there any way of avoiding batteries running flat when not in use?
NiCd and NiMH batteries self discharge approx 20% in the first day after charging and then 1-2%/day after. Most will be flat within 1-1.5 mths. Ideally charge the battery prior to use.

Can a battery be left on charge to maintain full charge ready for use?
The more professional type tool batteries can be left on the charger for a few days but most manufacturers recommend removing the batteries out of the charging unit once the charge cycle is completed. It is necessary to plan ahead for work requiring battery power.

Some power tool chargers supplied require charge times in excess of 2 hours. Is it possible to charge these batteries quicker?
Most of the tools with batteries that take longer than an hour to recharge cannot be charged more quickly with readily available equipment. Most of the professional grade tools charge in an hour or less.

It is understood that one of the principal reasons for budget priced tools being cheap is that the battery packs supplied are of lesser quality. Is is worth having the batteries repacked?
Yes that is correct, manufacturers reduce the cost of the tools by using "ordinary" batteries and "simple" chargers. Professional tools always use either Sanyo or Panasonic cells in their NiCd and NiMH tool batteries. Repacking is a good way to improve the battery and make it last longer.

Does this mean when looking to purchase a new cordless power tool, buying only one that is powered by Lithium ion batteries?
Lithium power tools are the lastest generation and the batteries do have such characteristics as staying charged and lighter weight with higher voltage. However, in general they are expensive and the battery/charger systems involves special circuitry to prevent overcharging/over-discharging as either of these can result in fire or explosion. Gradually lithium will reduce in price and be more widely available. It is quite likely that these batteries will have a limited life of 2-3 years.

Are there any general recommendations regarding maintenance of batteries and chargers?
One of the major problems with budget type tools and batteries is overcharging. Users tend to leave them on overnight when only 3 hours is required to finish the charge cycle. Most plug pack chargers require the user to terminate the charge (professional tools are automatic). Use the formulae above to calaculate the correct charge time for your particular battery. Use a timer if you are not going to be around to terminate the charge. Keep contacts clean and dry - rub with scotchbrite if corroded.