Saturday, June 9, 2018

Battery on my new Librem 13

Last month, I finally bought a new laptop. My Lenovo X1 Carbon (1st gen.) still performed well, even at six years old (2012). I think that's partially because I'm running Linux, which has less bloat. CPU loads were usually fine, unless I was really pushing things. The real problem was the battery. After six years of use, the battery held a charge for less than three hours. Not bad, but annoying when I want to work all day.

Sure, I could buy a new X1 Carbon battery for less than $100, but I was also worried about the laptop failing unexpectedly, and just when I needed it. I do a fair amount of work from home (especially writing) and it would suck to have my laptop die when I was trying to get something done. So I finally decided to buy a new system.

After waffling between "do I buy a new laptop?" and "maybe I should just get a desktop," I decided on a new laptop, but with an extra monitor and keyboard that were more comfortable. And soon after that, I decided on the Librem 13, by Purism. (In case you're curious, I'm also running an ASUS VE248H 24" Full HD 1920x1080 2ms HDMI-DVI-VGA Back-lit LED Monitor, and a Perixx PERIBOARD-512 Ergonomic Split Keyboard. I bought those elsewhere.)

I don't often travel with a laptop, but when I do, I prefer to use my primary system so I don't have to keep things synced. And I wanted it to run Linux. Purism is aimed at the Linux market, and I wanted to support that. Go Purism!

My remaining question was "how to manage the battery?" I know laptop batteries don't last forever. But how should I run my laptop so the battery lasts the longest? I remembered that it's not a problem with modern batteries to leave them plugged in all the time, but then there's the heat issue. Heat will kill a laptop battery. An article on How-To Geek answered Should I Leave My Laptop Plugged In All The Time? with a kind of non-answer. There is no straight answer. From the article:
Ultimately, it’s not clear which is worse for a battery. Leaving the battery at 100% capacity will decrease its lifespan, but running it through repeated discharge and recharge cycles will also decrease its lifespan. Basically, whatever you do, your battery will wear down and lose capacity. That’s just how batteries work. The real question is what makes it die more slowly.

Laptop manufacturers are all over the place on this. Apple used to advise against leaving MacBooks plugged in all the time, but their battery advice page no longer has this piece of advice on it. Some PC manufacturers say leaving a laptop plugged in all the time is fine, while others recommend against it with no apparent reason.
I found an interesting question on the Purism discussion board providing advice on battery use. User "Uncle_Vova" recommends "never discharge it completely" and "never keep it at high states of charge (say, above 60%) at high temperatures (above 50°C)." Later in the discussion, user "mrtsolar" also advises "Keep charge between 20-80% when possible."

That pretty much matches what I had found elsewhere: all laptop batteries degrade over time, eventually all batteries will hold less charge and not last as long between charging. But there are some things you can do to extend the life of a laptop battery: don't always keep it plugged in, don't let it go all the way to zero, let its charge stay within a range, avoid heat, take the battery out (if you can) if you're going to leave it plugged in all the time (like at the office, especially if it's in a "dock").

I suppose I could have looked into a power/charging threshold. Doing this is very dependent on the system firmware. I learned via an Ask Ubuntu forum there was a feature to do this on my Lenovo laptop, but I never tried it. I just plugged the laptop into a power strip, and I turned the strip off and on when needed. That usually kept the laptop battery between 15% and 99% charged, depending on when I remembered to turn off/on the power strip.

Being lazy, I wanted a way to automate that when using my new Librem laptop. Again, I could look into a power/charging threshold for the Librem. But for less than $20, I picked up a power strip that had a timer (Century 8 Outlet Surge Protector with Mechanical Timer). Four outlets on the strip are always on, and four are connected to a built-in timer. That allows me to plug in my monitor and LED desk light to an always-on outlet, and my laptop to a timed outlet. I still turn the power strip off when I'm not using the computer, but that's a habit I've had for ages, so that's not a big deal.

The power needs for a laptop aren't that big, so I'm not worried about over-taxing the power strip. This thing is built to run high-load devices like an aquarium water pump and light, or a heat lamp for a terrarium. The Librem runs a pretty light load in comparison: about 60-80W when charging the battery, according to user "Derriell" on the Purism forum.

I'm still tweaking the duty cycle. My goal is to exercise the battery somewhere between 20% and 80%. The Librem 13 will run on battery for roughly seven to nine hours, and it takes upwards of four hours to fully recharge, so right now I have the power strip timer set at five hours "off" and three hours "on." So if I only have the power strip turned on when I'm using the computer, the laptop is running from battery for five hours, then it charges for three hours, then it's back to battery. I have to keep the total (eight hours) evenly divisible by twenty-four hours.

Maybe I'm overthinking it, but this seems a good solution to me. How do you manage the battery on your laptop? If there's a more elegant way, let me know in the comments.