Bicycle Lighting - Batteries - Nickel Metal Hydride
- My personal favourite power source at the moment - NiMH (Nickel Metal Hydride) are now easily available in forms that are usable by cyclists. Their virtues and drawbacks are similar to those of NiCads, but generally they pack a bit more power for a bit less weight, which is good. Capacities are increasing steadily and AA cells rated at 2.5Ah are now available.
- Critics would say they are a bit less robust in use - and of course they are more expensive.
- Charging is similar to NiCads but they do require a bit more care to avoid overcooking. They tend to lose charge when not in use.
- New very high density 1.2V 4Ah cells are now available, making possible a 5 cell 6V 4Ah pack weighing just 300gm, which is a match for Lithium-Ion performance. For information dowload the Toshiba datasheet.
- For more information on the care and recharging of these batteries, visit
- Duracell's special NiMH area.
- Cadex NiMH page in-depth information.
- Battery Test NiMHs tested and compared, by Dave Etchells at Imaging Resource
- Here is a table of possible 4A-h configurations, to drive a 6V 6W bulb for about 4 hours. Value For Money (VFM) and Power For Money (PFM) figures below assume middle-of-the-road UK prices.
- 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.
Battery type v A-h wt(g) price charges ED VFM PFM
SLA 6 4.0 850 13.10 100 2.8 90.9 21.4
Cyclon 6xD 6 5.0 1200 25.00 200 2.5 156.7 26.1
NiCad 5xD 6 4.3 675 30.00 200 3.8 98.3 29.1
NiMH 10xAA 6 3.2 350 20.00 100 5.5 38.4 14.6
new NiMH 10xAA 2.5Ah 6 5.0 320 14.00 100 9.0 80.0 70.0
NiMH Dura DR11 6 3.6 360 80.00 120 6.0 20.7 11.5
NiMH 5x4Ah 6 4.0 300 35.00 100 8.0 42 29
Lithium Ion 7.2 3.2 300 120.00 100 7.7 10.5 7.0
Lithium Polymer 5.4 3.2 200 110.00 100 8.6 4.9 4.9