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cordless tool tip to pass on

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  • cordless tool tip to pass on

    i am an electronics technician by trade, love woodworking and such as a hobby. the members here give so much in knowledge and tips and i have learned a lot on that subject i want to give something back in return. i have given a few things, but not enough for me to consider myself a worthwhile member. so i am always looking for new things to share here...and i may have found one..

    as many of you know, battery chargers for cordless tools over time begin to get less and less efficent until they quit working. some people just buy a new charger, because they love the tool...and this is fine, but is expensive

    others just say the hell with it and buy a whole new tool

    and there are that few (probably the minority of the three) that pay to have their charger fixed. and that is not always cheap. this is where i can help

    over time, being moved around, and such begins to degrade the unit. in addition, the heat that is generated from a battery being charged slowly takes its toll on the circuitry inside. the heat over time causes the solder joints to break down. the "elements" also play their toll on the circuit board. the sawdust and such that gets inside isnt much help either.

    before you buy new batteries, buy a new tool, or pay to get your current one fixed, grab a screw driver and open the charger. clean out all the saw dust and brush off the contact side of the board with some alcohol

    then grab a soldering iron. more than likely all that needs to happen is that the grounds need to be resoldered. over the years after the unit is exposed to different temps and such, the joint becomes weak. it becomes weak as the solder joint gets old, loose, corroded, etc and begins to develop a resistance. by cleaning and resoldering these joints you get your resistance between the board and to ground back down near zero ohms, which is what is required for electricity to flow. when i open one i do the above but i run my soldering iron over each joint. they are small units and this does not take too long. after doing this clean the surface of the board again with alcohol. this gets rid of the flux and whatnot that can cause your board to corrode. put it all back together after the alcohol dries, plug it in and pop in a battery. this should fix the problem. if not try both batteries. if neither works, you might have 2 bad batteries. not likely but possible. if the charger seems to be working again, then it probably is and either you have two bad batteries or a bad tool. if you have another tool that accepts the same battery (most makita useres do), then you can isolate your problem quickly. what you can do beyond that is grab a multimeter and measure the value of the battery after charging. if it is the correct voltage on the terminals of the battery, you have a bad tool. if the batteries have no charge you are faced with a 50 50 shot as to guess if the charger is bad or the batteries are bad. if it is only one battery with no voltage it is obviously a bad battery. if neither have a charge, you need a new charger

    hope i did not confuse anyone and i hope this helps at least one of you


  • #2
    Good Post Ed, great advice.

    I've have quite a few chargers, and I'm sure this advice will help me some where along the line.

    What about cell phone chargers? Even though my charger stays in one place, I've noticed my cell phone battery barely lasts 12 hours now. A full charge when it was new would last near 48 hours.
    John E. Adams<br /><a href=\"\" target=\"_blank\"></a>


    • #3
      Use denatured alcohol. regular alcohol will degrade the non metal components, especially rubber and some plastics.


      • #4
        you can also measure the output of the charger. you should be at least a few tenths of a volt above the rated battery voltage to as much as 5 volts above because of no load on the charger. try to slip a little foil or bare 26 to 30 gauge wire between the battery contacts and the charger contacts when you plug in the battery to measure the charger output under normal load (don't short out the contacts though...). it will probably be within a few tenths of the battery voltage (a guess) unless there is a problem. a good subject to discuss since it applies to most people. hey woody, you probably didn't let the cell phone battery discharge far enough before recharging it. nicads especially exhibit a 'memory' of remaining power in the battery when recharge takes place and consequently lose power quickly when approaching that spot. you can't really revive the battery like you can with a lead acid cell and a deep discharge cycle. just try to let the new battery you get in the future discharge more fully before recharge.