The lifespan of ultra portable battery?

Hello,

The main goal for Ultra portable notebook like HP's DM3 & Toshiba's T135 is extended battery life without AC. But how long would the battery last to still be considered function (where it holds at least 70-80% charge)?

Thanks,

 

Probably the same as any notebook battery. Over 2 years.

 

Moral hazard is correct. In general, laptop batteries don't last longer than the expected lifetime of the product, which is 2 years.

 

I think one thing is heat.

My Sony's battery has 7,2% wear - most of that is from heat from the X3100 on Intel graphics drivers instead of the Sony ones...

So if your battery stays reasonably cool it will last long - if the cooling is weak and it gets heated up a lot then it will die pretty quickly.

 

What degrades a battery that is in use (not in storage) is three things.

1) Time - 2-3 years is my experience (avg) when I start to consider replacing with a 'fresh' one. If I have properly taken care of it in the first place.

2) Heat - the cooler I can keep the system and therefore the battery - especially when its charging - the closer I can expect 3 or more years from it. For this reason I always use a notebook cooler (85% + of the time) when I am able to have it with me (and not look like too much of a geek).

3) The number of recharges the cells have endured. If you fully recharge, use and recharge your battery 2 or three times a day, every day - then the life expectancy is closer to 1 year than 2 or 3 when used with to a 'normal' usage pattern of one recharge/discharge per day. The number of charges is right around 1000 that the battery is holding close to its rated charge (taking normal wear into account).

You may note that two and three are interchangeable and can and do influence each other. The more you recharge in a 24 hr period the hotter the cells are getting used at... (avg. over time).

Other little things to keep in mind is that a partial charge is still counted as a 'full' charge - contrary to what might seem 'logical' or expected.

Also, if you fully discharge the battery to 3% or less and don't charge it up within an hour or so (depending on the state of the battery cells, this 'grace' period may even be for a day or slightly more - but can also be less than 10 minutes on badly degraded cells), one or more of the battery's cells may drop to 0% charge and may even go into a reverse polarity mode that will kill the battery as effectively as if you had used it for 10 years.

So, the lifespan of an ultra portable's battery is dependent on how many times you charge it daily. How cool the notebook runs (and whether or not you keep it cooler when you can - especially during charging) and how long you need or expect it to deliver 'xx' hours of run time.

A little tip that I've been using for a long time is to not only charge the computer on a notebook cooler, but to actually have it 'on' when its charging. This slows down the rate of charge (on most systems) and is better for the cells by not breaking them down as much as a faster charge pattern can.

With all the above techniques in use, I have managed to get almost 4 years of use from HP and ThinkPad notebook batteries. Not only did the extra year surprise me, but they both still delivered the same run time as when new, up until I sold them.

With a little bit of proper use/maintenance, I see no reason that a low power CULV system should not give similar results (normally, we don't run the 'little' computers at full tilt and full temps, do we).

With an notebook and/or ultra portable, use a desk instead of your lap when possible to keep the system as cool as it can be. Raising it a little on the back seems to help dispel any heat it generates and also makes typing easier (for most people). This is why I like high capacity batteries that stick out and also stick 'down' - to raise the notebook on their own.

Hope this answers your questions.

Cheers!