Bicycle Lighting - Batteries - Zinc Chloride
- Zinc Chlorides (eg Ever Ready Silver Seal, Kodak Red, Panasonic Green) are familiar primary batteries. They are outperformed by Alkalines for most lighting applications, but they are cheaper and considerably lighter, so there are a few low-power situations where a long run time is not required where Chlorides may be the better choice.
- They are totally unsuitable for high power lighting applications, with current drains of 1 Amp or more they do not perform well, giving a poor quality of light and a very short run time.
- Running a low powered light, something like a 3v 1w bulb, they offer a very good weight-effective option, and in terms of Value For Money (VFM) they outrank Alkaline C and AA cells.
- Different brands differ considerably in weight and performance. Out of several brands tested in controlled conditions in 1991, Panasonic Green were easily the best (and the heaviest), while the inexpensive Boots brand also performed quite well.
- Here is a table of possible 4A-h configurations, to drive a 3V 2W bulb for about 6 hours. Value For Money (VFM) and Power For Money (PFM) figures below assume middle-of-the-road UK prices. D cells are much more cost-effective than the smaller packages, C cell or AA cell, and in practical terms are the only option for a long run time.
- For the best performance, power-to-weight, see the ED figures. For the best value, look at the VFM. For performance at a good price, check out the PFM column.
type weight(g) V A-h runtime ED price VFM PFM
+------------------+-------------------+----+------+--------+
ZnC (4 D-cells) 400 3 5 7.5 3.8 4.0 3.8 1.9
ZnCl (2 D-cells) 200 3 3.8 5.7 5.7 2.4 4.8 4.8
Alkaline(2 D-cells) 280 3 8 12.0 8.6 2.9 8.3 5.9
Alkaline(2 C-cells) 138 3 3.4 5.1 7.4 2.7 3.8 5.5
Alkaline(6 AA-cells)132 3 4 6.0 9.1 4.3 2.8 4.2
Lithium Sulph(4xAA) 60 3 3.4 5.1 17.0 10.0 1.0 3.4
Alkaline(2xD rechargd)280 3 6.5 9.7 7.0 2.9 9.1 6.5
+------------------+-------------------+---+-------+--------+