Alkaline Batteries

A couple of clarifications or amplifications:

Q1A ... and in many chemistries for rechargeable batteries, trying to draw more current from a dead battery can permanently damage it.

Q1B: It is worth noting, for the sake of the OP, who seems unfamiliar with batteries, that batteries are usually cells connected in series. For example, a 12V SLA car battery consists of 6 cells in series, with each cell having a full-charge voltage of about 2.1 volts, for a full charge battery voltage of 12.6 volts. This terminology, however gets almost constantly misused with regard to small cells (typical flashlight "batteries", etc) which are routinely single cells but called "batteries".

Q2 Battery rejuvenation is when some of the charge of a fully discharged battery returns to the battery through no known external charging.

This term is more often used in conjunction with SLA batteries, and refers to the reversal of sulfation (lead sulfate crystals, which accumulate especially when the battery is at a low charge level) by repeated charging to just short of the gassing voltage. It is also used to describe a process in NiMH cells in which very high currents are pushed through (briefly) to break up dendritic crystals. Here, the current source is apt to be something like a welder. I would not recommend this (second) practice, because one can easily imagine the cell exploding.

"Recovery" is the term more often used to mean the spontaneous increase in voltage that occurs slowly (over 10 - 20 minutes or more) after removing a load from a battery. This is what sometimes allows a car to start after you've turned off the lights (which you inadvertently left on) and waited for the battery to regain its strength.

Yes, I got the terms rejuvenation and recovery transposed. GA.

I'm not sure that it matters with the OP but while one is rejuvenating a NIMH or SLA battery one will certainly not be drawing power from them, too. I presume one could design a circuit to switch between the three modes of discharge, charge and rejuvenate. But I would expect that this would be dangerous to the battery and the local vicinity. So I wouldn't want this to be an automatic function.

It is possible to recharge a zinc-carbon battery using lop-sided AC, i.e. an AC waveform where the +going wave is bigger than the -going wave. Amateur electronics magazines have shown useful circuits in the past.

No specific answers to your questions, but if you want to learn more about batteries in general, check out Battery University here:

BatteryUniversity

The site is provided by Cadex, and company that makes chargers/analyzers for the battery industry, so may be a bit biased, but I have learned a lot from their informational site.

Tom D.

Question2 Battery Rejuvenation means to restore it to an original condition.

Just a few more links to helpful information...

Electropaedia
http://www.mpoweruk.com/index.htm

Energizer Tech Info: (Not limited to just Energizer brand batteries.)
Battery Handbooks: Comprehensive manuals (PDF) covering standard primary cell chemistries
http://data.energizer.com/Static.aspx?Name=AppManuals