Lost charger adaptor for battery drill. What's inside them?

agulesin

agulesin

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Having searched the Forum and found 177 threads mentioning similar subjects I'm apprehensive to start yet another thread, but here goes!

My Dad's cordless drill (one of the "cheapo" ones) has lost its charger adaptor (the bit the battery stands in to be recharged) so the drill is useless at the moment. We have the original "wall wart" which has a 16v output (14.4v battery) so I was thinking to just connect it straight to the battery terminals with croc clips.

As far as I know the current will reduce as the batteries approach 16v, therefore there should be no need for current limiting.

Does anyone know what's inside those adaptors - the original had two LEDS - red for charging, green for charged. I imagine they all have a similar circuit to each other...

Thank you for your assistance!
 
nicad or li-ion

li-ion do NOT use without the correct charger
 
Last edited:
If the battery has three teminals forget about connecting the "wall wart" directly to it. The third terminal is a feedback to the charging controller about the state of the battery pack. It might only be a temperature sensor ( when fully charged the battery starts to heat up and this is the signal fo the charger to stop charging ) or it might be more complex than that.

Even two terminal chargers can be very "intelligent" as to how the battery is charged with the charging current / voltage being altered as the battery charges.

In fact forget completely about connecting the wall wart directly to the battery. It might be 16 volt nominal and might in reality be considerable more than 16 volts.
 
Hi Guys,

Thanks for the replies!

More details: Ni-Cd battery, 14.4v 1.3Ah. "Direct Power" is the make of the drill.
 
+1 for binning it and replacing with a new drill!
 
your best bet is to look for one on ebay as a full kit for spares and repairs and just check the charger works
 
GOOD NEWS!!

Found the little b*****!! It was somewhere it shouldn't have been, and I'd passed it about 10 times every day without noticing!!

I'll publish the circuit in case anyone wants it - watch this space!
Cordless charger.jpg

Thanks once again for all your help ;)
 
glad you found it
thanks for letting us know it makes it all worth it(y)
 
Here we go:
Drill-charger-adaptor.jpg


Green LED is on all the time, not quite sure what red LED is for...

R2 is 5 watt, others 1/4 watt.
 
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