Battery Care

Charging

• Do not overcharge - a battery that is already fully charged should not be recharged again.  This may shorten the life of the battery through over-heating or cell leakage.
• Keep your batteries cool.  Charge them in the shade or indoors.  After use allow batteries to cool for a while before recharging.  Do not put them in the fridge as this can cause condensation to form inside the case, leading to corrosion and other damage.  The recommended temperature range for charging is 10^oC - 40^oC, the battery will get a better charge and longevity if it is recharged within this temperature range.  Continual exposure to high temperatures will affect the life of the battery.
• When the tool speed starts to decrease, it is time to recharge the battery.  Do not make the tool "labor" as this can damage the internal cells.  Do not discharge the battery to the point where the tool can not turn or function as this can have the same damaging affect.
• Charge the battery just before a job and use it for the full charge to get longer run time.  All rechargeable batteries naturally self discharge about 10% in the first 24hrs and 1% per day thereafter.
• Folllow the manufacturers instructions - many chargers have "trickle charge or maintenance charge" functions that can be helpful in maintaining good performance.  Some older model chargers must be turned off after a certain time period, it is important to do this otherwise the battery will be damaged.
• It is common to damage batteries of "budget" power tools that use plug pack/transformer chargers by overcharging.  One way to avoid this is to charge using the following formula.  Calculate the battery capacity eg (1300mAh) x 1.4, divide the result by the output of the charger eg (400mAh) giving charge time in hours.

New Battery Packs

• Must be fully charged before use.
• Will need to be fully charged and fully discharged or "cycled" as much as five times to condition the battery to perform to its full capacity.
• Batteries work better if exercised regularly - the internal chemistry of the battery needs to be in an active state.  Charging and using the tool regularly will help to achieve this.
• When charging the battery for the first time - the charger may indicate that charging is complete after 10 or 15 minutes.  This is normal.  Simply remove the battery from the charger/device, re-insert it and repeat the charging procedure.

Storage

• Ni-Cd batteries should be stored discharged.
• Ni-MH batteries should be stored full charged.
• If possible use batteries at least every month to keep the internal chemistry active.
• A battery that has been stored for a long time may need conditioning to get it to regain full battery performance.

At the Worksite

• Avoid short-circuiting the battery pack with metal objects across the terminals - drill bits, nails and screws can do this easily within the tool carry case.
• Avoid moisture and water around the battery packs and chargers.
• Avoid big shocks or dropping of the battery.
• Avoid heat as much as possible.  It is normal for batteries to get warm during use and charging - let them cool down prior to putting on the charger.

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.