Purchase Price :- $23 for charger c/w two 3.7V 750mAh RCR123 cells.
Extra cells $6 each, 12V Car Adaptor cord $1 each. Shipping $5.50

SPECIFICATIONS:

Model: R/ICR123A
Constant Voltage : 3.7V
Capacity : 750mAH ( min. 720mAH ) - tested at 0.2C discharge with end voltage 3.0V
Dimensions : 16 X 34mm ( +/- 0.3 to 0.8mm )
Weight : 18 g

RCR123 PCM SPECIFICATIONS:

Overcharge Detect Voltage : 4.35V
Overcharge Reset Voltage : 4.15V
Over-discharge Detect Voltage : 2.5V ( 3.0V under load )
Excess Current Threshold : 6A
Excess Current Detect Voltage : 0.2V

This is my first rechargeable CR123 system and was bought mainly to use with the Mr Bulk LionCub range of torches. But I am sure it will also find many other uses among my growing collection.

Thanks to AW on CandlePowerForums for supplying these at such a great price. The shipping was faster from Hong Kong than some items I have ordered in the U.K! Impressive.

There are several types of Rechargeable CR123 cells on the market at the moment. Protected and unprotected types. The unprotected cells have no electronics on board to prevent overcharge or over discharge. With these the user must me careful not to go outside the cell parameters or damage or worse will occur!

The cells provided with this device are of the protected variety. This means that each individual cell is fitted with its own PCM (Protection Circuit Module). This gives several very important features to the cell.

Control over the maximum and minimum voltage into and out of the cell on charge and discharge.

Control over the Charge and discharge current flowing through the cell on charge and discharge.

So in a nutshell the protection stops you from doing anything stupid to the cell and should ensure it has a long useful life span and does not burn down your house. That said I would always ensure you charge cells in a safe environment under supervision.

The chemistry involved in Lithium Ion cells is a little temperamental at best and once you have a problem the amount of energy contained in such small area can result in something that you don't want to be anywhere near when it happens. I use similar Lithium Polymer cells for my RC model planes and charge these in a fireproof container. I have personally seen what happens when you overcharge these cells. With thermal runaway the resulting explosion and fire are not something you want inside your home.

The next thing we need to understand are the voltage of these cells. This is Lithium Ion chemistry and has a nominal 3.7 Volts for the cell. A normal Primary (Non Rechargeable) Lithium cell has a nominal 3 Volts per cell. So you need to be careful when using the rechargeable cells in equipment not designed for the higher voltage. This is even more important if the torch for instance take two cells in series. As the resultant higher voltage from the cells would probably pop the bulb or destroy the electronics. Always check before you use them!

Right that's enough on warnings and safety! Lets have a look at the actual charger and cells!

As you can see in the pictures the charger is made from an injection molded shell with provision for charging two cells at the same time. There is a single two colour LED in the corner of the unit and a socket for the 12V DC power.

My unit came supplied with a universal voltage 100-240 50/60Hz switched mode power adaptor. This delivers 12V DC at up to 380mA to the charger. This was a two pin device that does not fit UK plugs, but it also came with the UK to two pin adaptor so no problem. I also bought the optional 12V car adaptor lead. So that when I go camping I can charge all my cells up.

The charger is simple to use. Just plug in the adaptor, attach it to the unit and put the cells the correct way round into the charger.

The LED on the unit light up green with no cells inserted. Once the cells are added and it is charging the LED will light up red. Once the cells are fully charged the LED will turn green again.

I assume from this the LED is set to detect the current flow in the circuit. With current flowing it will turn red.

I think we need to explain little about how a Lithium Ion cell is charged now. The charge profile is a little different to most other rechargeable systems.

Assuming the Lithium Ion cell is mostly depleted before the start of the charge the following will happen. The charger will start to charge the cell in constant current (CC) mode. This limits the current flowing into the cell to a pre determined value. This is a good thing as we don't want to charge a Lithium Ion cell too quickly as it will heat up and possibly damage it or reduce the useful life. The CC mode will continue until the charger detects that the cell has reached a pre determined voltage level. At this point the CC mode is terminated and the cell is charged in Constant Voltage (CV) mode. The charge voltage is held constant and the current will slowly taper off as the cell reaches the target value at which point the cell is fully charged. A longer explanation with pictures is available here :- www.batteryuniversity.com

Because this charger is capable of charging two cells at the same time it is important to make sure that both cells are at a similar state of charge before charging them. If in doubt about this then charge them one at a time. Because the cells have their own built in protection circuits any small imbalance between them will not be a problem as if the voltage or current level is exceeded the PCM will switch off the cell protecting it. This should also protect the cell if the charger goes faulty for any reason.

I have used the cells in my Mr Bulk LionCub and had excellent results. This light takes a single cells and has its own built in electronics that cut off the power at a safe level. I also have a Nuwai Quantum III Light which will also run on these cells.

Because the cells have PCM's they can also be used in series on two cells lights. Again be careful as to the voltage but something such as a DownBoy 917 as used in my Aleph should be fine.

Manufacturer:- not known

Dealers

Please see this thread on www.candlepowerforums.com