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I don't want my laptop's battery to always be at 100% because it lessens battery life, especially when above 25 Celcius, the lowest summer temperature in Israel (currently 30C - 32C). I prefer to keep the battery level between 30% and 50% and use it instead of a backup UPS battery. Is there any software that can do that?

If there is no software, can I wait until the battery reaches 100% charge, pull out the power cord and work in battery mode until it reaches 10% so Windows 7 will let me know or will automatically hibernate? Moreover, the battery can protect against brownouts and power outages.

Will having the battery with the power cord plugged in degrade battery life faster than unplugged? Would I be better using UPS? Will UPS be cheaper over the long-term compared to a laptop battery?

I have Lenovo G560.

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up vote 4 down vote accepted

It is true that keeping it plugged in all the time will usually shorten battery life unless you take measures to control the charging cycle. Manually unplugging it & drainign the battery down periodically (e.g., every couple of weeks) can help to extend the life.

On my Lenovo ThinkPad I use the ThinkVantage Power Manager to control the charging process. Other manufacturers may provide a similar utility. (If there is a way to do it natively in Win7, I'd like to hear about it.)

In ThinkVantage Power Manager, switch to Advanced mode. Click the Battery Tab. Press the Battery Maintenance button.

screen capture

It's pretty self-explanatory - you can adjust the options there to get what you want.

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I know that older type Ni-Cd needed to perform the charge-discharge-charge again cycle to keep optimal state and capacity. However, I was told that new Li-ion and Li-pol batteries do not require it and that intentional draining of the battery can even have negative influence on it. – Juhele Jul 13 '11 at 9:41
@Juhele And i heard that Lithium Polymer batteries have a chance of exploding. – Boris_yo Jul 13 '11 at 9:55
@yosh m Thanks. I have lenovo G560. Do you know if lenovo provide such utility for my laptop? Do you know how to contact them? – Boris_yo Jul 13 '11 at 9:58
@Boris_yo - yes, I know. This can happen in case of impact or battery case perforating. According to my information, this was a problem mainly of the akkus in solid metal casing which allowed temperature and pressure to increase and later led to explosion. Now, the main case is mostly soft plastic so the gas products of the chemical reaction can go out freely without explosion. – Juhele Jul 13 '11 at 10:11
@Boris_yo - in addition, this was also mainly problem of cheap Chinese akkus without electronic protection - I remember the case about the fake Nokia cellphone akkus, originally some very poor quality ones from China. These could explode during charging or even when simply using the phone. – Juhele Jul 13 '11 at 10:14

Accepted answer is for Lenovo, but the original question did not mention specific device brand. Original poster undisclosed his laptop type later. The general answer to original question is:

There is no universal tool, support depends on particular manufacturer.

Reason: design of charger circuits and their ability to limit charging is dependent on device manufacturer.

Some, like Lenovo or Dell are consistently seen to support charge level limitation across their models. Utillity to control charging circuits is included in pre-installed toolset or can be downloaded from their website.

Other manufacturers, like Apple, are not seen with any support of this feature.

You can always confirm this for your laptop brand by searching, for example

ASUS limit battery charging
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