Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
dewalt 14.4 drill battery
my battery has died and no longer accepts a chrage. any ideas? i have
read about and tried the deep freeze, thaw , charge thing and it did not work for me. can anyone tell me which terminals are postive and negative? i have also heard of "jump starting " the batteries by applying a short current across the terminals. it worked just fine until a few days ago |
#2
Posted to sci.electronics.repair
|
|||
|
|||
dewalt 14.4 drill battery
"allenone973" wrote in message . .. my battery has died and no longer accepts a chrage. any ideas? i have read about and tried the deep freeze, thaw , charge thing and it did not work for me. can anyone tell me which terminals are postive and negative? i have also heard of "jump starting " the batteries by applying a short current across the terminals. it worked just fine until a few days ago If you need your drill to be reliable, eg for your business, forget about trying to revive the battery pack. Even if you manage to get it to take a charge, it is likely worn out and will give poor running times and poor charge retention. Once one or more cells become weak, when a load is placed across the battery, ie your drill, the weakest cells take a reverse charge from the stronger cells which causes permanent damage to them. A DeWalt drill is likely to draw several Amps, and this high current reverse charge will kill cells very quickly indeed. My advice is to buy a new pack, or if you are handy you could probably repack the old one with new and possibly higher capacity cells, which may or may not work out cheaper. Bear in mind all cells must be changed together, it's no good just replacing the obviously weak ones. A common way of trying to get individual cells to take a charge after they have developed an internal short is to pass a substantial current through them to 'blow' the short. It can work but IME it is a short term measure at best. Just attaching a large current source across its terminals to zap shorts won't work, the shorted cell(s) have to be identified and zapped individually. I have used large capacitors charged from a bench power supply in the past to zap shorts, usually upwards of 2200uF, the bigger the cap the bigger the current pulse. However, too large a capacitor could cause the cell to fail completely or even explode. You certainly shouldn't zap the entire battery by shorting it out- this will likely make things very much worse or even cause cells to explode. Dave |
#3
Posted to sci.electronics.repair
|
|||
|
|||
dewalt 14.4 drill battery
"Dave D" wrote in message news Just to add to my last post- you might want to check that the internal thermal/current cutout inside the battery pack hasn't failed open circuit. If you are getting no reponse from the battery at all, ie drill not turning at all, zero volts across the battery terminal, that is a possible cause, and rather cheaper/easier to fix than failed cells. Bad cells would usually give increasingly poor performance up until its failure. The fact that it seems to have suddenly stopped working implies a component failure either inside the battery, the charger or the drill itself, rather than bad cells, but without further info I can't really speculate further. Does the charge light (if any) come on when you try to charge the battery? Dave |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Flaky Dewalt 18v battery | Home Repair | |||
Funny lathe machining problem.... | Metalworking | |||
Sony Clie TJ27 - battery problem | Electronics Repair | |||
Cordless Drill Battery | Home Repair | |||
Bench Top Drill Press That Can Swing Drill Head | Woodworking |