subject: tool maintenance and battery care [print this page] POWER LOSS: POWER LOSS:
do not run the cordless tool until the tool stops moving. you can reverse polarity in some of the cells within the battery, making them unchargeable and unusable. in effect, turning an 18 volt into a 14.4 volt battery. in fact, as soon as you notice a loss in power in the cordless tool, switch the battery.
CHARGING:
some batteries can be left in the charger indefinitely, others cannot be. during normal use, a battery will heat up. when it's time to switch-out a battery, some companies recommend, removing it from the tool and waiting up to 30 minutes (depends on the brand), allowing it to cool to room temperature, before placing it in the charger. other chargers will cool down the battery pack if it's too hot before charging it. some companies do not recommend charging a fully charged battery, as this will over charge battery. other companies have chargers that will not allow this to happen.
TRICKLE CHARGE FOR MAXIMUM BATTERY LIFE:
charge batteries in the charger for six to eight hours, or overnight, at least once a week. twice a week is recommended. this "top-outs" each individual cell within the battery with full capacity, allowing them to hold the originally designed amount of charge. if this is not done, over the long term, batteries will retain a "memory effect." this means that, over time, charging the battery will be less complete, eg some cells may be drained during use to 10% of capacity, others may be drained to 40%, and 1-hour charging may only charge these cells back to 40% and 70%. you could also look at it like an 18 volt battery will be partially charged into a 15.6 volt and every subsequent charge will only charge the battery to 15.6 volts. leaving the battery in the charger overnight will "top-out" these cells to 100%. memory effect is also caused by repetitive, slow, steady use of batteries, mostly from electronic or flashlight use. power tools are typically used under varied, "high-drain" applications, so this type of memory effect is not usually an issue.
EXTREME TEMPS:
avoid extreme temperatures when storing batteries. batteries should be kept above freezing and below 100 degrees. this means don't leave them in your truck overnight in winter and don't let them bake in your cab in summer. what i do is i have a padded cooler with wheels for my front seat just for cordless tools. if it's cold all day long, i put those hand warmer packs inside to keep the batteries above freezing. in the summer time, i use sun shades for the windshield and i put a frozen water bottle in a plastic bag, in the cooler, no ice because it will melt. caution, if the temperature difference, from the ice to the battery pack, is too extreme, condensation may occur within the battery pack. only add the ice pack if temp is well above 100F outside. in the winter, at night, i bring my cordless tools (or batteries) inside for the night.
CHARGING IN EXTREME TEMPS:
read manual for optimum charging temperatures, it's usually around 40 to 100 degrees F. during charging, a chemical reaction within the batteries is taking place. if it is too hot or too cold, this reaction is compromised. each tool company offers different charger features. some chargers will not charge a battery if it's too hot or too cold, only just right. others can sense the temperature and will wait until the temperature is within the acceptable zone. some will go thru the process of charging, but only provide a limited charge, this can permanently damage the battery, causing all future charges to only have the same limited charge. the general rule is not to charge in extreme temperatures, but sometimes you don't have a choice. if you're on a job site, in below freezing conditions, like i have been, you need to use your cordless tools. often, i will place a halogen light close to the charger and battery to give it the necessary heat needed to provide a good charge.
BRUSH CHANGES FOR OPTIMUM POWER OUTPUT:
every tool, used daily, should have its brushes changed once a year. MAKITA tools have externally accessible brushes, so anyone can do it, saving you $80.00 in labor costs at the repair shop.
DUST:
job sites are dusty from drywall, saws and general craziness. dust can collect on the charger's circuit board and over heat it causing the charger to die, an expensive fix. protect chargers from dust, especially when charging. i keep mine in an old metal tool case. this keeps the dust out and protects it from an accidental kick or tool drop. when using tools in a dusty environment, blow them out with compressed air frequently, chargers too. keeping dust off the motor, prevents excessive heat build up, so the tool can operate at peak performance.
BATTERIES IN TOOL BELTS:
metal filings, screws, nails and metal hand tools can touch the contact points of a battery and short out the battery and subsequently the cordless tool. if you must carry batteries in your tool belt, put those plastic battery caps, that came with the new tool, on the battery contact ends before the battery goes in your belt. if you threw them away like most people, thinking they were just extra packaging, you can buy new ones from the manufacturer. a shorted-out battery can cause a fire.
BATTERIES:
NiCad (Nickel Cadmium) batteries dissipate charge when not in use. it can be up to 20% the first day and 10% the next day, but only 1 to 3% the following days. Lithium-Ion batteries retain their original charge for months.
NiCad batteries function better than NiMH (Nickel Metal Hydride) batteries in cold and freezing weather. NiMH batteries are sluggish at cold temperatures and should be allowed to warm up before use. NiCad's can operate down to -20 degrees F. Lithium batteries will operate normally down to -4 degrees F.
NiMH batteries offer longer runtime per charge than NiCad's, but the overall charge cycles are less; they wont last as long as NiCad's. Lithium-Ion batteries have longer runtime than NiCad's and NiMH's and they offer twice the overall charge cycles.
