Old Asus Laptop Plugged In, Charging 0%

Digerati · 02 Apr 2016

Certain number of times? I believe that is a myth. Got a link?

While batteries are commonly rated for a specific number of "cycles", I have never heard of one that refuses to charge because some arbitrary number is reached.

There are often, however, monitoring circuits (firmware) that will prevent a battery from charging if there is a fault condition noted in the battery. These include shorts inside the battery, excessive heat, or reversed polarity - that is, when some unsafe condition is encountered.

I note too that notebook batteries, especially with older notebooks, do occasionally need to be calibrated with the notebook's charging monitoring circuits. The notebook manual will show how to do this - though typically it says to unplug the charger, run the notebook until it discharges to the point it automatically goes into hibernate mode. Here's a decent guide from the How-to Geek: How to Calibrate Your Laptop’s Battery For Accurate Battery Life Estimates.

Note too you cannot run a battery to 0V in a working notebook. However, because the chemical action never fully stops in a battery, if you put a notebook with a discharged battery in drawer or on a shelf and leave it there for many months, it can go completely dead, and need to be replaced. For this reason, you should always charge a battery before putting it in storage. And best to remove the battery from the notebook too.

Mellon Head · 02 Apr 2016

Itaregid said:

Certain number of times? I believe that is a myth. Got a link?

Once the connection to the battery terminals is established, charging should be possible. If the charge current stops after 30 seconds, a digital code may be required. Some battery manufacturers go as far as to add a defined end-of-life switch. If a preset age, cycle count or capacity is surpassed, the battery stops functioning. When asking why such codes are added, the manufacturers explain that enduring safety can only be guaranteed if the battery is tamper-free and well performing. This makes common sense but the leading motive may be pricing. In the absence of competition, replacement batteries can be sold at a premium price. Newer batteries are generally more service friendly than older ones.

(Emphasis mine)

From:
Can laptop batteries be repaired?

And:

Some battery manufacturers add an end-of-battery-life switch that turns the battery off when reaching a certain age or cycle count. They argue that customer satisfaction and safety can only be guaranteed by regularly replacing the battery. Mind you, such a policy also rotates inventory.

From (which is, I believe, the source of the first article. I would tend to put more credibility into this one):
BU-911: How to Repair a Laptop Battery ? Battery University

And just for interest sake, here's an example of needing to work around the DRM in a battery because of manufacturer lockdown (yes, they really do it). The comments are especially enlightening (btw, these are guys who know what they are doing):

Unlocking Thinkpad Batteries | Hackaday

The Smart Battery Specification, http://sbs-forum.org/specs/sbdat110.pdf has a parameter for "Cycle Count" to keep track of how many times the battery has been discharged. Why should it be a stretch of the imagination that a manufacturer uses that cycle count to kill the battery after a certain number of discharges? As a system, a laptop battery is very intelligent, and it has to be for safety and efficiency. Why wouldn't a profit driven OEM take advantage of that fact? It doesn't surprise me in the least that a manufacturer would go to these lengths to sell more batteries. They do the same thing in laser printer cartridges.