Why use Rechargeable Batteries?
If your lights take standard AA or AAA batteries, I would highly recommend the use of a good set of rechargeables. The brightest battery operated lights usually have a battery life of only a few hours. For these the economic benefits of using rechargeable batteries don’t need explaining. Some lights however have an advertised battery life running into tens or even hundreds of hours. In this case, it’s tempting to think rechargeable batteries aren’t really necessary. However, it’s often the case that the brightness of these lights is not maintained throughout their battery life and actually, for a large proportion of the time, the light shows little more than a glimmer. By using rechargeable batteries and charging them on a regular basis, the light will always deliver its maximum brightness.
Best Rechargeable Batteries
There are a bewildering range of rechargeable batteries on the market from very good to complete rubbish. Fortunately, some of the very good ones are now very competitively priced.
There are two basic options:
i) Go for a high capacity standard rechargeable battery. For AA, the highest capacity is now at about 2900mAh. For AAA, they go up to around 1100mAh. Be aware that batteries don’t always deliver the capacity claimed. These Uniross AA 2700mAh Batteries and these Uniross AAA 1000mAh Batteries are very good.
ii) Look out for the new ‘low self discharge’ batteries. These have slightly lower capacity (2000mAh for AA and 850mAh for AAA) than those above but they have the massive advantage in that they stay charged up for much much longer when not used whereas standard rechargaebles tend to lose much of their charge within a few months. In this category the Sanyo Eneloop AA 4 Pack Batteries 2000mAh and the Sanyo Eneloop AAA 4 Pack Batteries are recommended.
Availability of the low self discharge batteries means that rechargeable batteries are now more appropriate for a much wider range of applications. Which is best for your bike lights really depends on how regularly you plan to use them. If you only occasionally use your bike at night the low self discharge batteries are probably a good choice as you wont then need to be quite so organised in having to remember to charge your batteries every time you go out.
Update – I’ve just noticed that there are now some higher capacity low self discharge batteries available. The XX AA Eneloop batteries have capacity of 2500mAh so seem to offer the best of both worlds. The choice seems to have become easier!
I highly recommend the use of an ‘intelligent’ charger. I explain why in my next post.