There’s a lot of confusion out there about rechargeable battery technology.
Is the memory effect real? Do modern rechargeable batteries suffer from it? Should you discharge batteries completely before recharging? Should you charge batteries whenever they’re not in use? Does overcharging damage the battery? What are the differences between NiCd, NiMH, lithium-ion, and lithium-polymer batteries?
In this case, confusion leads to disinformation. Some people often say to discharge lithium-ion batteries completely to avoid the “memory effect”, even though most of the sources I’ve seen say that completely discharging a lithium-ion battery is bad.
Forget it. Batteries should be more intelligent. Sure, there currently are “smart batteries” out there that report things such as chemistry type, number of charge cycles, voltage levels, and temperature, but do users care about these things? Do users know what they mean? The batteries (or the devices that use them) should be smarter and tell users what matters:
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Estimate time left on the current charge. Making accurate estimates is difficult, because many devices do not consume power at a constant rate. Manufacturers want to avoid complaints from users who say, “your device said I had 1 hour and 15 minutes of battery life left, but I really had only 50 minutes!” Instead, device manufacturers often don’t say anything at all.
Truly smart batteries or devices could generate statistical data and usage patterns. Even with variable power consumption, they ought to be able to use such data to compute reasonably accurate estimates. When in doubt, they should be conservative with their estimates.
If nothing else (and to rip off an idea from Mac OS), if you can’t be accurate, be less precise. For example, a better estimate might be “About 1 hour” or “About 30-60 minutes”.
- When to recharge. Smart batteries or devices can know their chemistry type and could tell the user the appropriate charging behavior to follow. Messages such as, “You should recharge your device now to maximize the lifetime of the battery” could be used to supplement existing low battery warnings. Overcharging should never be a problem; smart devices already detect when the battery capacity is reached and stop automatically.