I know the shelf-life of the 123a is up to 10yrs, but I'm trying to find out what the shelf life would be for a rechargeable 123a. If I drain a battery, charge it and store it because I have dozens of rechargeable 123s in rotation, how long would the charge last?

Search on Candlepowerforums for that type of information.
Somewhere they had a whole page or link to whole page on caring and feeding of your lithium based cells to include dangers.


TAKE CARE AND CONSIDERATION FOR YOUR SPECIFIC APPLICATIONS AND THEIR VOLTAGE AND POWER LIMITATIONS.

Rechargeable Liion in general should be stored at 80% charge for maximum retention of capacity.

Bumping the top repeatedly or the bottom of the capacity in general lowers capacity over time.  So don't leave it in a cheap charger that continually comes back on as surface charge voltage is lost.
Don't use it till it stops in a device then turn it back on when the voltage comes back up from resting without putting it in charger.
A friends kids did that with his and his 16340 cells wore out pretty rapidly.

Liion cells lose up to 10 percent capacity each year.  Not charge but actual capacity.

Controlled environment in a house is best place for your cells.
Do not leave in car in summer or deep cold etc.
I have a number of unprotected cells I can keep in a Solarforce host with a LED drop-in in my car and not care much about heat or cold.  These unprotected cells were salvaged from bad laptop batteries by removing tabs, sanding smooth, charging while checking voltage with a multimeter before and after charge to verify 4 out of 6 were still good and only two cells in the laptop battery were bad.  I've even used such cells to run incan bulbs for short periods which is a pretty heavy current draw.  I do not recommend this and all this is done at your own risk.



I've pretty much gone completely to single rechargable cells like the 18650, 16650, and 14500 to avoid any problems with smaller 16340s.  

Nimh AA Eneloops are a much safer cell chemistry and stand up to more abuse in cold and heat. A Solarforce host with an extension and spacers can be used to run 3 AAs at the same time giving you enough voltage to run an adequate LED drop-in and keep a charger and flashlight in car with plenty of cells.

I'll assume that you're talking about 16340 li-ion 3.7v cells and not RCR123 3.2v LiFePO4 chemistry, which are both rechargeable, but have different voltages and may not be interchangeable in some lights.

Regardless, you never want to store li-ion cells at 100% if you're not going to be using them for say a few months.  For the 3.7v (4.2v hot off the charger) cells, discharge them down to about 3.6v-3.7v and put them in a Ziplock baggie and then into the fridge.

They'll last longer.  For the 3.2v RCR123 cells (3.6v hot off the charger), you can discharge them down to 3.2v and do the same.

Both those levels are about 40-50% state of charge.

Let them come up to room temperature before mucking with them, however.

Chris

Two things kill 123 rechargeables, which are not a replacement for 123 primaries due to voltage issues.

Number one is heat. The higher the heat, the faster they lose capacity... and they are always losing max capacity.

Two is voltage/charge the higher the charge, the faster they are losing capacity.

The very worst is combination of both. You can lose 10-30% capacity in a MONTH if you have a fully charged li-ion cell and put it in a car during the summer. That's not charge... that's a permanent loss of capacity.

As stated already, have 50-80% charge on cell and stick in back of fridge to store long term. It will still lose capacity each month, but only .5% to 1% a third of that if there is no protection circuit.

Li-ion cells are also always losing charge, not related to permanent capacity. If it discharges itself below the normal minimum capacity, it is going to be a dead cell and not work again. So I'd charge cells with a tiny bump charge annually if you run em at 50% for storage. 80% should last for 2 years.

The worst thing of all is running a trickle charge on a full battery, leaving it in a charher after it is full and in high heat. One summer on a trickle charger, inside a car, guarantees a dead cell. Also why keepimg a fully charged spare in a car is a bad idea. When that is necessary, don't have more than 1 spare and rotate the cell in the light, and keep a third in room temperature or fridge with 80% charhe to rotate in. This should get you 2 years out of a 3 cell rotation. Beyond 2 or 3 years, it's best to just buy new cells when you need them, as the prices go down, capacities go up, and you don't deal with aged cells.

As you can see... since li-ion works for hundreds of recharges and will age out in just a couple years anyway, it makes little sense to stack em deep for SHTF. Even unprotected li-ion stored in perfect condition lose 2% capacity permanently every year and once the fridge goes out SHTF, self discharge skyrockets. Since lithium primaries hold 80% 10 years and get used up in one shot, they make more sense to stack deep. The Eneloop low self discharge NiMH batteries make the most sense for SHTF type power, because they last thousands of charges, only discharge 20-30% a year with 10% permanent capacity loss only occurring after many years of storage, provided  you never let them discharge to zero, at which time they will still provide years of use.

For my daily carry light, I really like running 16650 battery, one battery usually will last me about a month ( I use my EDC all the time)  I keep a couple 123 in my backpack should I loose power in my 16650.  I use the charger that came with my Peacekeaper (18650 battery).  The cost is $13 for one battery... so if the battery only last a year its paid for itself the way I go though 123 previously.