Gadget lovers like myself who care about the environment and want to save money on battery purchases need rechargeable batteries and a good charger to go with them. And that's where La Crosse Technology's BC-900 AlphaPower AA/AAA Battery Charger comes in.
Slow Down and Chill Out
Although most of the inexpensive NiMH (Nickel Metal Hydride) battery chargers pride themselves on how fast they recharge your batteries, it turns out that super-fast charging is about the worst thing you can do if you want to get full capacity and many recharge cycles. Without a temperature sensor, quick chargers tend to overheat the battery, and many have no voltage sensor either which means they can also overcharge the battery. Both of these behaviors can reduce the life and capacity of the battery.
Ideally, you want batteries (both NiCD and NiMH) to be charged gradually and without getting excessively hot. And you definitely want your charger to have built-in voltage sensor so it knows when to step down the charge rate from full charge to a gradual trickle charge. This way you can keep your batteries in the charger and know that they'll be fresh and ready to go when you need them without risk of over-charging.
The La Crosse BC-900 charger includes both a voltage sensor and a temperature sensor. In technical terms, the charger uses the "minus delta voltage" (-dV) charging method to bring a battery up to full charge then step down to a gentle trickle charge current when the battery reaches its capacity. If, during a charge cycle, the battery temperature exceeds 127 degrees Fahrenheit, charging is disabled until the battery cools back down. This safety mechanism protects both the batteries and the charger itself - no one wants to wake up to a melted battery charger all over their nice granite countertop!
The BC-900 also features adjustable charge rate, all the way from 200 mA (milliAmps) to 1800 mA. At its highest current, the BH-900 can charge a 2000 mAh (milliAmp hour) capacity AA battery in about 70 minutes and that's plenty fast for most purposes.
The charger supports both Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMH) batteries up to a rating of 3000 mAh. For electronic devices with fairly demanding power requirements, NiMH batteries tend to be a better choice. However NiCd batteries still have their uses in devices such as solar lights where the higher capacity of a NiMH battery would be wasted.
The Gadget-Lover's Gadget
The BC-900's display is packed with useful information about the health of your batteries and their current charging status.
When I saw all the modes and read-outs the BC-900 charger, I knew I had to have it. Current voltage, charge rate, capacity, charging status - all neatly displayed on individual LED screens for each battery. I keep it on my desk so I can look over and watch the read-outs and hit the "display" button to switch between time in cycle, total capacity, charge rate, etc. just because I can!
The key features of the charger are its TEST and REFRESH cycles. These allow you to TEST the capacity of any NiCad or NiMH battery and then (if necessary) REFRESH the battery to its optimum capacity by taking it through a series of gentle discharge and full charge cycles.
Some of the NiCD batteries in my solar lights were down from their rated capacity of 600 mAh to a capacity of just 50 or 60 mAh after months of use outdoors in irregular sunlight. After a couple of times through the REFRESH cycle, the batteries were back up to 450-550 mAh capacity - ready for action next season. For NiMH AA batteries, the REFRESH mode brought similar results, restoring capacity of some tired old NiMH batteries from about 500 mAh up to 1800 mAh - about 90% of their rated capacity after several years of irregular use.
The charger can't work miracles (it was not able to revive my 8-year old low capacity NiMH batteries that hadn't been holding a charge and had been sitting unused in a drawer for years), but it did a good job revitalizing several newer NiMH and NiCd batteries that had been subjected to poor charging from cheaper quick chargers and simple timed battery chargers. If you have a few NiCd or NiMH rechargeable batteries that are not holding a charge for very long, then it's worth running them through the RC-900's TEST and REFRESH cycles - you may just find that you're able to squeeze some more life out of these old batteries, which is better for the environment and for your pocketbook.
The BC-900 charger is fully compatible with the newer "hybrid" or LSD (low self discharge) NiMH batteries such as Sanyo's "Eneloop" brand. LSD batteries come pre-charged and hold their capacity much longer than standard NiCD or NIMH batteries retaining up to 75% to 85% of their capacity after one year on the shelf. Traditional NiMH batteries can lose 30% or more of their rated capacity after a single month with no use. This makes LSD batteries a much better choice for remote controls, headphone amps or digital cameras that may go days or weeks without active use or that need to provide small amounts of power over longer periods of time.
The Memory Myth
A myth persists that modern NiCD or NiMH batteries must be allowed to discharge completely in order to prevent a "memory" effect. In other words, if you use a battery for only half of its capacity then recharge it repeatedly at the half-way point, the battery will only last half as long "remembering" the voltage point at which it was previously re-charged. This was based on observances in the early days of NiCD technology when batteries on satellites (charged via solar panels the exact same amount every day) developed reduced capacity over time because the cells were not being fully discharged before being recharged. While this was true of battery designs many years ago, modern NiCD and NiMH batteries have no such memory effect.
In fact, in many cases the exact opposite is true: when you use multiple rechargeable batteries together in a single device (e.g., 4 AA batteries in a digital camera), you should actually be careful not to let the batteries drain all the way to zero otherwise you may experience something called "polarity reversal" which can damage the batteries and lower their capacity.
Polarity reversal happens when multiple batteries of different capacity are discharged together. When the weakest battery discharges to zero, the other cells cause a reverse charge on the discharged battery. This can cause permanent damage to the weaker cell. Even if you match identical brands and identical capacity batteries individual cell variations do exist which can cause the batteries to discharge at different times.
And this is another way that the BC-900 can help you get more life out of your batteries. In the "Test" or "Refresh" modes, you will find out exactly what each battery's capacity is in milliAmpere Hours. By matching the batteries with similar capacities together, you can minimize the risk of reverse polarity, thereby preserving the batteries' capacity.
Final Thoughts
At a street price of around $45, the LaCrosse BC-900 charger is a bit expensive as battery chargers go, but it is a worthwhile investment for any voracious consumer of AA and AAA batteries. It will help you get more life and higher capacity out of your NiCD and NiMH batteries and this will save you money in the long run. Using rechargeable batteries is much more cost effective (and environmentally friendly) than using alkalines and now with pre-charged LSD batteries available and with standard NiMH battery capacity approching 3000 mAh, there are lo longer any performance or convenience benefits left to using alkalines.
Save the planet, one battery at a time. Go buy one.
Where to Buy:
BC-900 Specifications/Features:
What's in the Box:
Manufacturer's Contact Details:
La Crosse Technology
2817 Losey Blvd South
La Crosse , WI 54601
Phone: 608.782.1610
Web site: http://www.lacrossetechnology.com/
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