Lithium Ion vs Nickel-Cadmium (Ni-Cd) Rechargeable Batteries?

October 2007 - after so many years using Ni-Cd why the switch to Lithium Ion Batteries?

The New Maxum 620 and Maxum 1250 torches are now available and will ultimately replace the existing Classic 620, 620 Speed, Classic 1250 and 1250 Speed.

For over 30 years Erich Kowalski has been a firm supporter of the Nickel Cadmium (Ni-Cd) batteries used in Kowalski Torches and Video Lamps. He has moved with the fast developing technology regarding these batteries (more properly known as Accumulators) and they have matched or surpassed the performance of others economically available on the World markets.

Erich has also studied carefully the performance of the Nickel Metal Hydride (Ni-Mh) batteries used by many of his competitors and found them severely wanting. Lithium Ion (Li-Ion) batteries have been, until recently, far too expensive to make them economically viable.

The Cadmium in Ni-Cd batteries is, however, a heavy metal that is not easily disposed of safely and, as a result, it has been decided that its use in batteries will not be permitted for any new goods sold within the European Community after 25th September 2008, except for some specific instances.

In 2005, in anticipation of the restriction in the use of Ni-Cd batteries, Erich Kowalski began to redesign the full range of his Diving Torches, using an alternative power source. His conclusion was that Li-Ion batteries were the only realistic and best alternative to power his lamps. As a small manufacturer, producing entirely hand-built specialist lamps, this has been a very long and exhausting procedure, but I am pleased to say that it is nearing its end. The introduction of the new Maxum 620 and Maxum 1250 torches is the first stage of this transformation.

FAQ on the new battery law and how it will affect existing Kowalski owners.

Future disposal of Ni-Cd batteries.

....but while Ni-Cd batteries are still in use .... we still need to deal with the ....

Ni-Cd memory effect
The notorious memory effect is often used to diminish the value of Ni-Cd batteries. The truth is; all other rechargeable batteries are affected as well, but not necessarily to the same extent. More important is the fact that the memory effect does not really play a role in respect of underwater torches. Other phenomena need to be considered with the memory effect. Imagine that you use an underwater lamp like a cordless phone. You recharge (not overcharge) it constantly, then use it for a short period of time (let us say a maximum of 5 minutes). Then, you recharge it again and repeat this cycle over and over again. After a certain period of time you would find a decline in the operating time of the lamp. The worst-case scenario will be that, after a period of six months, you can only use your torch for 5 minutes.

What happens in the cell?
The chemical process takes place only in a small portion of the cell. The other portion is entirely unused and becomes inactive. As a rule, underwater torches are used much longer than for 5 minutes. The memory effect will not occur when the lamp is occasionally used for a only a few minutes or operated at 50% output. Often, a decline in the operating time is considered memory effect. But the decline in connection with underwater torches originates for other factors.
If a lamp is in use for 1-3 weeks only and kept in store for the rest of the year, the cells are severely affected due to the occasional use.

When stored for a long time, crystals start growing in the cells. These crystals block off the charging in the very area where they are located so that this area is not available for storing energy. This is why the capacity of the cell decreases. The crystals can grow to such an extent that a short circuit can occur. In most cases the cell has already lost its capacity and a short circuit current will not flow, so the cell cannot be recharged.

Therefore we recommend for torches with Ni-Cd batteries:
Use your underwater torch on a regular basis (once a month, even in your bath tub if necessary!). The batteries will achieve a long lifetime with many charging/recharging cycles.