If you are old enough to remember when disposable alkaline batteries were the only batteries you could buy, you might also remember how we used to test them. Needless to say that it is not so easy to test lithium-ion batteries. As a result, knowing when they are reaching end-of-life is more complicated.
Lithium-ion technology is a completely different ball game, according to the folks behind Pale Blue Earth USB rechargeable batteries. Though you can test current charge level with any voltmeter, there is no way to test how much life a set of batteries has left in it.
By contrast, you can check alkaline battery life with a piece wire and flashlight bulb. Just bend the wire so you can make a connection between the positive and negative terminals. Then touch the bulb to the wire. The brighter the light, the more power your battery has. This simple test works with alkaline batteries because full discharge equals end-of-life. As for lithium-ion batteries, all you can do is watch for warning signs.
1. They Don’t Last As Long
One of the first signs that lithium-ion batteries are reaching end-of-life is not lasting as long. Maybe you could power your MP3 player for several days when the batteries were brand-new. Now you are barely getting a single day out of them. This is a good sign the batteries are wearing out. It suggests they are not recharging as fully and possibly discharging more quickly too.
2. Restarting During Charging
If you are dealing with something like a cell phone or a laptop, another telltale sign that the battery is reaching end-of-life is random restarts during the charging process. Maybe you are charging your phone while eating lunch. You look over and notice that it suddenly restarts without any action on your part.
Laptop computers will sometimes do the same thing. This is typically the result of the device not being able to accurately measure how much juice is left in the battery. Inaccurate measurements trip up the power management software, resulting in a quick shut off and reboot.
3. Instant Drop in Charge Level
Yet another telltale sign is an instant drop in charge level immediately after charging is complete. This happens more frequently with laptop batteries. You might charge your laptop to 100%. But when you unplug it, the battery suddenly drops to 50%. This is a clear indication that the battery and computer are not communicating.
Your battery might be telling the computer it is fully charged when it is not. The opposite could also be true. The laptop could be telling the battery to stop charging because it’s full, even though it is not.
4. Unusually Fast Discharge
A similar situation occurs when batteries discharge unusually fast. This is different from the first point of batteries not lasting as long. In the case of a laptop or cell phone battery, it may slowly discharge when you first unplug it, but then you notice a quick drop an hour or two later. You might drop instantly from 80% to 40%, for example.
Unusually fast discharge rates signal that your batteries are not holding as much charge as you think they are. They might also be discharging unevenly because the chemical process inside is no longer consistent.
Testing alkaline batteries was easy back in the day. Even today, you can drop one on a hard surface and get a good idea of its charge level by observing how much it bounces. Lithium-ion batteries are entirely different. The only way to know they are reaching end-of-life is to pay attention to how they behave.