I have a 12V 2A NiCd battery which I want to charge. I have a power unit that puts out 18V 14.6A. Can I use it to charge it? Would the battery just draw the current it needs or would it always put out 14.6A? The battery will be used to power a fan I want to install in the car for my dogs :).. get that AC air in the back seats

Picture of battery and power unit here:

power output says 25V but can be lowered

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    \$\begingroup\$ No. You need a NiCad charger, built specifically for charging NiCad batteries. The NiCad charging process is current-controlled, and most certainly not constant-voltage. \$\endgroup\$ – uint128_t Jun 23 '16 at 1:41
  • \$\begingroup\$ Battery charger's don't spit out a constant voltage, they usually spit out a constant current until the battery is like >90% charged or so then they switch to a constant voltage charge, using a voltage higher than needed can (and often does) result in some kind of battery failure (in the case of Li-Ions overvoltage WILL result in smoke/fire/general doom). Can't you run the A/C from the car battery? \$\endgroup\$ – Sam Jun 23 '16 at 5:11

Definitely DO NOT attempt to charge your 12 volt battery with that power supply - it will do its best to get the battery voltage up to 24 volts (or whatever voltage it is set to). The battery will probably be destroyed (perhaps violently) by the resulting high current.

You should only use a charger designed to charge 12 volt NiCD batteries to charge your battery.

  • \$\begingroup\$ I was guessing this would be the answer.. shame shame. Thanks for taking the time! \$\endgroup\$ – Gil Jun 23 '16 at 15:36

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