Tip & How-To about Computers & Internet

Laptop Batteries how to make them last

This actually applies to any device that uses a Lithium type battery. Some of this will apply directly to those devices but differences in hardware or software may limit that. The batteries work the same but the stuff they connect to is going to control everything.

If you have a laptop (or other device) powered by a lithium battery you will notice that over time the useful run time decreases. Eventually your laptop will run for a few minutes at most then shut down. So the first thing you will get told is your battery needs to be replaced, and most of the time that will be true. However, sometimes the battery is fine it just needs to be recalibrated.

On a typical laptop you should get two years of use out of it without it loosing much capacity. I actually have a laptop that has a 12 year old battery that holds full rated charge. I've had a new laptop that the battery was suspect after about 6 months but was fine. And I've managed to get some dead batteries to come back to life. There are no secrets to doing this, you don't have to buy anything, and you just need to do a few simple things. Basically think of this as battery maintenance. It's free so that has to be cheaper than the alternative which is battery replacement. If you have already had to replace the battery then you'll be able to make the new one last.

A lithium laptop battery isn't just a battery, there is actually a microcontroller that manages how the battery is charged and this is called a BMS or Battery Management System. The reason they use a BMS is that to properly and safely charge a lithium battery it needs to be charged at a certain rate and finish charging in a certain way.

First thing, we need to know how a lithium battery likes to be treated. This is pretty simple. You shouldn't use more than about 40-50% of the battery capacity. That doesn't mean you can't, but you definitely do not want to drain the battery dead every day. So use the battery and when it hits 50-60% on the meter plug it in if you can. Second, a lot of people will use the laptop much like a desktop and leave it plugged in all the time. This can be as bad as draining it too much. The battery does need to get 'exercised' or used on a regular basis. So at least once a week you want to use the battery. And about once a month you want to use it to the point where it runs out of charge. This monthly deep discharge helps reset or calibrate the controller or BMS. This is the one time where it is a good thing. Normally you want to avoid this at all cost. So the bad things are a lot of deep discharges or none at all. It's a short list but if you think about it that is all you can control.

What if your battery really isn't that old but the meter says it is acting like it is? Do I have to replace the battery? Well this is one of those times where a bit of luck can save you buying a new battery you don?t need. That BMS system also works with another system that is an information and control system. There are several names for this such as HCI or Hardware Control Interface (Toshiba Laptops). There are other names but basically this just lets your laptop hardware talk to your operating system and vice versa. Sometimes the battery is fine but what talks to it isn't accurate. So it will be telling you the battery is low or is bad when it still has lots of useful life. When a lithium battery actually goes bad it will be one cell inside the battery, out of the 6 or more cells inside. The BMS and other monitoring stuff have no way of knowing it is only one part of the battery so it can't compensate and say the entire battery is bad. The battery will also lose a bit of capacity with each charge cycle. Since these systems are not really sophisticated they will after a while be out on the accuracy.

To calibrate or recalibrate you need to do a bit of research. Each manufacturer will have different systems. Some will actually have a reset button on the battery. Some will use calibration software and other will use a special discharge/charge cycle. My Compaq uses the button and software, one of my Toshibas uses just software and another uses the cycle. When you do the recalibration it forces the system to measure the discharge rate and the time. When complete it then knows the new value of how much time or capacity your battery has left. Sometimes you will find that the battery still has plenty of life left. And other times you will find the battery does need to be replaced. Replacement batteries are much cheaper now but this is worth doing before you have to spend money.

Posted by on

Computers & Internet Logo

Related Topics:

Related Questions:

2 Answers

had this tablet for one day, its showing 50% .. battery, when should I recharge..


There's no harm in keeping it on charge all the time. Unlike older rechargeables, newer Li-ion batteries don't need to be broken in by running them down and then recharging.

Feb 12, 2015 | Tablets & eReaders

1 Answer

How do I recharge the battery on a Polaroid t1455 Camera?


Depending on the battery formulation, you may want to apply the proper type charger or AC adapter. More specific data in battery type would be beneficial to further answer. As lithium ion, nickel metal hydride, nickel cadmium and lead acid type batteries are all so different it would require the proper charger selection for the battery .

Jan 15, 2015 | Polaroid t1455 Digital Camera

1 Answer

Does the same apply for the NavMan S100T battery as you can buy replacement batteries for this model?


No. From the manual: "Your Navman contains a non-replaceable internal lithium-ion polymer battery."

Mar 05, 2012 | Navman GPS

2 Answers

Zen shuts off after only playing a few songs


How long have you been doing this for (months)? You may have already drastically reduced the life of your battery

Battery
& Charging

The Zen’s battery:

The Zen uses a 3.7v rated Lithium-Ion rechargeable battery. A 3.7v rated Lithium-ion battery actually gets charged to around 4.2v with a tolerance of +/- .05v. A charge of 3.7v/3.8v is actually about a 50% SoC. At 3.3v, lithium-ion batteries have typically only utilized 70% of its 100% charge capacity.

Charging Voltage = 4.2v (4.1v)
Nominal Open-Circuit Voltage = 3.7v (3.6v)

A note on Over-Discharging and Over-Charging:

In general, Lithium-Ion batteries do not like to be overcharged (usually above 4.2v) or excessively discharged (under 2.5v-3.0v). If a Lith-ion battery falls below 1.5v, then typically you shouldn't try to recharge it at all for "safety" concerns. A fully discharged lithium-ion battery causes the formation of copper shunt in the cell which begins to get extremely hot when attempting to recharge. A lithium-ion battery should not be charged above 4.3 volts. Above 4.3 volts and the cell causes lithium metal plating on the anode. The cathode material becomes an oxidizing agent and loses stability and begins releases oxygen. This can cause the battery to heat up. Lithium-ion cells should never get above 130°C (265°F). At 150°C (302°F) the cell becomes thermally unstable and can eventually lead to a thermal runaway. These are the safety reasons why the low and high voltage cut-off and temperature sensing circuits are used. If the internal temperature of the battery gets to high, the temperature sensing circuit can initiate a mechanical pressure switch that will permanently cut-off the current path and prevent anymore charging.

How do you charge the Zen (Battery)?

It can be charged by connecting it to a USB port on a computer or by using an AC Wall Charger within the Zen's charging specs (see below).

Can I use my cell phone's AC Charger to charge my Zen?

I believe the max input voltage of the Zen is around 5v. Most devices that can charge or run off the USB host power can handle the max 5v of USB ports. 4.2 volts is usually the max Lithium ion batteries are charged to. It is usually around when the high voltage circuit is triggered and stops the charging of the battery. I would not connect a charger to the Zen that puts out more volts then 5v with an output current beyond 2400mA (2.4A) to be safe.

When and how often to charge?

To be safe, I would avoid frequent full discharges because this puts additional strain on the battery and usually shortens its life. Partial discharges with frequent recharges are better than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no "memory effect" like with older type Ni-Cd (nickel-cadmium) batteries.

Do I need to charge the Zen for hours before I use it for the first time?

With Lith-Ion batteries, the first charge isn't any different then any other charge. There is no technical need to fully charge it the first time you get it other then the fact of being able to use it longer since it will have a full charge. They are not like other types of previously used rechargeable batteries that needed the full charge at first. Most likely by the time you get everything all figured out and loaded onto the device, the battery would be fully charged anyway.

Please note: I do recommend that you at least connect the Zen to a computer while it has sufficient charge on the battery in order to properly be detected and have its devices drivers load properly. In other words, don't use your new Zen for a period of time to where you drain enough power from the battery to just come on and turn off automatically or to the point the Zen doesn't come on at all. If you do, then you may have detection and charging issues when you go to connect the Zen to the computer.

How long will the battery in the Zen last?

Lithium-Ion batteries have a life span of about 300-500 discharge/charge cycles or 2-3 years from being manufactured.

Storing or not using the Zen for long periods of time:

Lithium-ion batteries (by themselves) with no built-in voltage monitoring circuit have a really low self-discharge rate (1-2% a month) when not being used. Having the addition of voltage monitoring circuits will slightly increase the discharge rate, but should not reach the point of excessively discharging the battery to where it won't turn back on unless sitting unused for an extended period of time and if its last state before powering off was a already in a low voltage state. So, as long as you aren't storing it for long periods of time at a low discharged voltage, the battery should be ok to recharge.

Accidently left the Zen plugged into the Computer all night or for a long period of time:

I wouldn’t make a habit of doing so. Long term usage like that could shorten the life of the battery. Although you may be fine for a while, leaving it plugged in occasionally all day and night, most likely won't hurt it, but leaving it plugged in every day and night may not be a good idea. Although once it is charged to 100%, the battery's internal high voltage cut-off circuit should keep the battery from over-charging and the devices charging circuit should keep applying a trickle charge when detected a drop in charge below full. However, keeping a Lithium-ion battery plugged in and fully charged keeps the battery's temperature elevated. Exposure to prolonged elevated temperatures can cause capacity loss which can then cause the battery to no longer be able to charge or hold a charge. Plus, it may be a small chance, but there is a chance that exposure to this condition for long periods could also increase the chance of a circuit failure (charging, high voltage, temperature sensing) and allow for a severe over-charge to take place to the point of thermal runaway which has been known to cause the occasional "exploding" battery, but in most cases just melt (and take some of the device with it) or catch fire.

A note regarding USB and charging:

Per the USB specs:
USB 1.1 = Minimum supply voltage is 4.4v
USB 2.0 = Minimum supply voltage is 4.75v
Both maximum supply voltages are 5.25v and a current of 500mA.

Before the USB bus interface can begin charging a device (Zen), it must return a device identifier to the hub driver (or device driver). Once the hub driver has the returned information from the device (like power requirements, supported transfer speeds, etc.), it can then begin charging the device based on those retuned values. This process is called Enumeration. Until enumeration has completed, it may not draw more than 100mA from the bus. Once enumeration has completed, it can then begin drawing up to the 500mA allowed by the USB bus.

Jun 23, 2008 | Creative Labs Zen Digital Media Player

Not finding what you are looking for?

149 people viewed this tip

Ask a Question

Usually answered in minutes!

Top Computers & Internet Experts

Doctor PC
Doctor PC

Level 3 Expert

7733 Answers

kakima

Level 3 Expert

102366 Answers

David Payne
David Payne

Level 3 Expert

14161 Answers

Are you a Computer and Internet Expert? Answer questions, earn points and help others

Answer questions

Loading...