[BrianL]

I have a NiCd powered Black and Decker drill. The original wall wart charger was 9V AC, but was lost. I have a 9V DC adapter, otherwise equal specs. Will that work without issue. I tried it for a couple seconds and it does power it, but I'm concerned that maybe the original 9V AC ends up much less than 9V after conversion to DC.

 

[Bluejets]

Nope....other way.... 9vac approx 12.6vdc

 

[BrianL]

in that case, a 9V DC charger won't damage anything then, correct? Other than maybe not giving a full charge. But it's only a 7.2V drill anyway. Why would it have a 9V AC charger?

 

[Bluejets]

in that case, a 9V DC charger won't damage anything then, correct? Other than maybe not giving a full charge. But it's only a 7.2V drill anyway. Why would it have a 9V AC charger?

Because one bucket of water has to be higher than the other for current to flow plus somewhere in the circuit will be a regulator where a voltage drop occurs.

 

[BrianL]

Sorry, what I meant was why they didn't use a DC charger.

 

[BobK]

Just because there is no electronics in the wall wart if it puts out AC. All the electronics can be inside the drill.

Bob

 

[BrianL]

That makes sense. Though it seems they're rather not have them in the drill.

Just confirming, I guess people are scared to say yes, but on paper, the 9V DC charger *should* be OK then, correct?

 

[Cannonball]

Yes

 

[Audioguru]

If the "7.2V" battery is Ni-Cad or Ni-MH then all 6 cells are fully charged to 1.5V which is a total of 9.0V.
The charging circuit might need an additional 1.7V for a total voltage needed of 10.7V.
The original 9VAC charger produced a peak of 9V x 1.414= 12.7V and the fullwave rectifier dropped the output to 10.7V so a 9VDC charger will never fully charge the battery.

 

[BrianL]

Thanks a lot, Audioguru. That's what I was thinking.