The UK Battery Shootout

Rechargeable batteries have now become so much a part of everybody's lives, almost to the extent that most of us could no longer live without them, and the one thing that's always confused us all is which ones are best? We are always told that the higher the capacity of the battery the longer it will last and the better it is for us! The performance of all batteries is measured by their capacity and capacity is measured in mAh. All manufacturers will tell you how wonderful their batteries are and shout about their capacities. But in the cold light of day, even when the price varies so wildly - anything from £7 to £15, what is it really all about?.

So in reality which ones are better than the others and which batteries really are the best?

I have used rechargeable batteries for many a year now and have always thought that I have had a good idea of what is a good battery and what is a pretender. But in reality, how do I really know?

I have been following the results of the 'Great Battery Shootout'  with interest now for several years and must admit that this bible of battery performance has without question been the inspiration for this web page. However, I have always felt that this was only partly useful simply because the vast majority of the batteries tested are either not readily available in the UK or simply unheard of this side of the pond. I have always wanted to take a closer look at some of Europe's and then even more specifically the UK's most popular batteries, but have never had any real way of comparing one brand against another. Until now. It suddenly dawned upon me that my latest battery charger, which is a very neat little LaCrosse RS900, is all I have ever been looking for!

This LaCrosse charger will perform in virtually the same way as the rig used in Dave Etchell's 'Great Battery Shootout'. One of  the best features of the microprocessor controlled LaCrosse charger  is it's ability to refresh or condition any type of AA rechargeable battery. What the refresh feature does is both very simple but equally unique at the very same time.

It will thoroughly charge a battery until a full charge has been detected and then when the full charge has been reached it will start to automatically discharge a battery at half the rate of charge at which the battery has been charged.  By discharging the battery at a known discharge rate, over the same load each time, the charger can calculate the accumulated capacity of the battery quite easily. This is made possible by the continual monitoring of the voltage and then the charge or discharge current over time, all of which is very efficiently controlled by the charger's central microprocessor system. The charger will continually repeat this charge/discharge cycle and measure the capacity each time. The charger will continue to perform this cycle until the accumulated capacity no longer increases past the previously recorded level and this last measurement is taken to be the actual capacity of the battery under test. By testing batteries in this way it is leveling the playing field in terms of results simply because each battery is being charged and discharged in exactly the same way each and every time.

Although this process may not be perfect from a purist's point of view, it is more than adequate for the general benchmarking of AA NiMH rechargeable batteries. When you think about it, all batteries are being subjected to the same test conditions. It is generally accepted that NiMH rechargeable batteries will not operate at full capacity until after a fair number of charges. Some will say two or three charge/discharge cycles, other will say 5-10 cycles. This charger will automatically charge/discharge batteries up to 20 times in one hit!. If a battery is not performing after 20 cycles it  is never going to perform. What is of real interest to me is which batteries attain the highest capacity compared to their manufacturers rating as displayed on the batteries themselves. Some manufacturers will never overstate capacities, others will claim anything as they have have never had a reputation to lose.

At the end of the day who's to know whether a battery has a capacity of 2000mAh or 2500mAh. We tend to believe what it say's on the tin and kid ourselves that we've had a good deal. Maybe we shouldn't - so let's see..

Below is a table of results for tested batteries to date  (all batteries are AA and of NiMH chemistry. Charged at 1000ma and discharged at 500mA)