I have a 12v xrp cordless drill. in the past 6 months i have purchase 3 new batteries. none will hold a charge. what is the problem.

If it is a Ni-CD / NI-Mh battery, please fully discharged and fully charged it to prevent "Memory effect".

If it is a Li-ion battery, please charge it before you use it.

Please keep in mind that, please fully charge a battery when you store it. And, charge it again every two months.

One thing I,ve found with cordless tool batteries is that if they're completely dead, the charger won't recognize them. Try hooking a known good battery with a charge up to the problem battery, terminal for terminal, with small jumpers. Leave it hooked up for a minute, maybe a minute and a half. this should be sufficient to provide just enough charge to bring the battery up to the "threshold level" required for the charger to recognize it. Then, simply charge the battery in the normal way. If this doesn't work, you may need new batteries, or a new charger. Hope this helps you.

Probably the brushes need replacing on the drill. Order new ones from a Dewalt parts dealer on-line.

Try placing the battery in a freezer for six hours before trying to charge the battery and if this doesn't work find a friend with a working charger and make sure using that method that you don't just have a bad charger.

Even though it is only 6 months old, the battery could be faulty here as it seems it is not holding any charge.

Try a new battery it sounds like a faulty battery

Does the drill do anything? Check in the cavity where the battery goes and make sure there is nothing there to prevent the battery contacts from connecting with switch. I take it the charger indicates the batterys are fully charged. If you cant see anything obvious I would take it back and get a replacement.
Dave

Are batteries for the dewalt cordless drill interchangeable? Will an 18 volt battery fit in a 12 volt drill?

if the battery are less than a yr old should be a warranty
if drill DC920 or DC925 they are on recall for switch. may be co'z the battery to die. have them check at ur nearest service center.

You'll need to do it yourself-dis-assemble the battery and check each cell individually to determine the bad ones. You can purchase replacement cells very inexpensive.