MacBook Pro Charge Limiting for Battery Health

Since working from home, my laptop is constantly left plugged into the mains as there isn’t much of a reason to ever disconnect, especially when you have a nice office to work in. I’ve been told leaving your laptop on charge has a negative impact on the longevity of your battery.

I’ve learnt this the hard way. The battery from my previous laptop, a Macbook Pro 2015, died a slow death until it got to a point where it soon became a glorified workstation. This seemed to happen quicker than I would have liked - within 3 years from purchase. Not something I’d expect from the build quality expected from an Apple product.

I was brave enough to replace the battery myself giving a new lease of life! The post teaser image is proof of my efforts. That picture was taken in when I managed to carefully pry the first cells of the old battery away from the existing adhesive. This was the most hardest part of the whole process!

My old laptop has now been replaced with the most recent iteration of the Macbook Pro, as I needed a little more power and most importantly 32GB of RAM to run intensive virtual environments. I made the conscious decision to actively take care of the battery and not repeat the mistakes I made in how I used my previous laptop. This is easier said than done especially when my laptop is connected via Thunderbolt to my monitor, both powering my laptop and gives dual-screen capability. It’s impossible to disconnect!

My only option was to find a “battery charge limiter” application that would set a maximum battery charge. Now, there is a great debate across forums whether going to such lengths does have any positive impact on battery health. Apparently, MacOS’s battery health management should suffice for the majority of scenarios when it comes to general usage. Going by experience, this didn’t help the lifespan of my previous Macbook’s battery. Hence my scepticism.

One indirect benefit of setting a charge limit is there will be less charge cycles counted, resulting in increased resale value should you decide to sell your laptop. Also, according to the Battery University, setting a charging threshold to 80% might get you around 1500 charge cycles.

If the likes of Lenovo, Samsung and Sony (all running on Windows) provide support software to limit the charge threshold, there has to be some substance to this approach. Unfortunately, you’re very limited to find a similar official application for macOS. But all is not lost. Two open-source variants carry out the job satisfactorily:

Both these apps modify the “Battery Charge Level Max” (BCLM) parameter in the SMC, which when set limit the charge level. The only thing to be aware of when using these applications is that sometimes the set charge limit can be wiped after a shutdown or restart. This is a minor annoyance I can live with. Out of the two, my preference was AlDente as I noticed the set charge limit didn’t get wiped as often when compared with Charge Limiter.

I’ll end this post with one final link from The Battery University on the best conditions to charge any battery - How To Charge and When To Charge.