How do I drain until "empty", rechargeable NiCad camera batteries ?

how can I drain them to empty, in the best and most convenient way, outside the camera

Don't bother. Drain them in the camera by leaving the camera on until the camera shuts down. That is what the manufacturer means, take anything a salesperson says to you with a grain of salt.

What would happen if it put them in some salty or slightly vinegar, water for half an hour before recharging them?

About what you would expect. Don't try it.

I'm a novice relating to electronic things. The only thing that I can think of as "happening" is some of the water becomes subject to electrolysis. Or maybe the batteries short circuits. Please tell me what someone with some knowledge knows what will happen. (Don't leave it to my curiosity.) Thanks.

Who told you it would be a good idea at all? I have heard of freezing batteries and high current pulsing older style NiCAD batteries, but submerging batteries in a conductive liquid is just going to damage the battery and any electronic circuit (such as manufacturer authentication and battery protection circuits) that are fitted inside the battery case (protecting the battery and preventing counterfeit battery packs from being used by the device).

Unlike your standard AA batteries many camera, cellphone and laptop battery packs have additional electronics in them. They are not generally designed to be deep discharged outside of the device they are designed for, doing so can damage the battery or in some cases reduce the voltage below a certain point preventing the electronic device from accepting it (giving you a faulty battery warning). Also it is totally unnecessary to do so with modern batteries (there were cases with older chemistry NiCAD battery cells, but not any more as far as I am aware).

If you REALLY want to discharge a battery you don't throw it in a bowl of conductive liquid, you use a device called a "resistor" which acts like a load and limits the discharge current. There is another device called a "wire" which does the same thing except it doesn't limit the current and can potentially damage the battery (and burn the users fingers).

See your other thread for my answer......

My Radio Shack Charger, from 6 years back , has a DISCHARGE/RECHARGE switch that I shift to DISCHARGE b4 charging. I don't remember how it tells you the batteries are discharged though.

Didn't like the other replies?

No. First I don't want to go out and buy something. I hav e a charger and it doesn't have a built in discharger. I don't want to leave the camera on unnecessarily. I want to take care of the camera. It's delicate instrument. It's the batteries that should get the treatment, not the camera. I want an answer that will open my eyes to something of interest, to do the trick not the mundane, that's why I come to experts. If people can make a battery from a potato, or an egg, or a tomato, maybe there's a good way to drain a battery with a potato, etc. - so tell me how, if it's possible. HN

Look at the rating of the battery and identify the Minimum Voltage.

Get a resistor and a LED that will allow current to flow until the Minimum voltage is reached and the LED goes off. The resistor will then prevent discharge below the Minimum voltage.

This is a basic application Ohms Law.

Do Not over discharge the battery, as stated above, and I'll state it again because it's important, if you overly discharge the battery the internal protection will not allow it to be re-charged and you will be replacing the battery.

Regards,
Sapper