Dewalt battery charger problem and possible heads up

[J. Clarke]

Left an 18v XR battery in the charger last night, in the barn. It went down into the 20s. Today I went to change batteries and it was stuck in the charger. I finally got it pried out and there was a smell of burnt plastic and the battery and charger were both partially melted, to the point that another battery wouldn't fit into the charger and the charged battery wouldn't fit into any tool I had.

Noticed that the charger is marked "do not use below 40F". Either they're real serious about that or the charger picked last night to die.

Went down to Lowes and got a couple of new batteries and a new charger for going on 180 bucks after tax. Was tempted by a cordless drill which with two batteries and charger was 129, but they were the smaller capacity batteries, the charger was the older design that doesn't do NiMH or Lithium ion, and I already have a better drill.

Be interesting to see if the new charger resurrects some of the batteries that the old one said were dead.

[Jerry - OHIO]

I had some 9.6 Maketa's that would kick the charger off so I hooked my bike trickle charger up to it and ran like hell, hour later it was up to full charge. I didn't know what 12 volt would do to a 9.6 ?? But it blew the crap out of a 7.2 after six hours.

Jerry

[J. Clarke]

Turns out it didn't. But it detected that they were bad a lot faster, and it doesn't reset itself when I pull a bad battery out and replace it with a good one--it has to be unplugged first. I'm not sure yet whether I consider this to be a useful feature.

[krw]

NiCds are charged with a constant current so at least in theory one could use a single charger for all voltages (a 12V battery is just 10 1.2V cells in series, a 9.6 is eight...). The current used is a function of capacity, so smaller batteries may use a different current. This doesn't work with Lithium batteries, however, because they're charged with a constant voltage. The charger has to know what voltage to supply the battery.