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I've had a previous MBP (5,3) with battery swelling. Looking around the stackexchange it doesn't seem too unusual even on newer models.

A bit of reading I've seen tells me this can be caused by keeping devices charged at 100%. I've been using fruit juice to remind me to unplug regularly. As I already have a system to alert me of when the battery is at a certain charge level, this is not what I'm looking for.

I was wondering if there's anything I could do to charge the battery on my current MBP (11,3) to a safe level, eg. ~80% charged, and keep it at that level while plugged in to the charger?

  • Possible duplicate of Battery Full Alert – Allan Apr 19 '18 at 2:24
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    Not looking for an alert, I have that already thanks @Allan. – Scottmeup Apr 19 '18 at 2:48
  • It's not about an "Alert" per se - the underlying problem is "preventing a battery from charging beyond a certain point." Your problem as in the dupe is attempting to regulate the charging of the battery which is already handled by the SMC and backed up by the over-charge protection circuitry. – Allan Apr 19 '18 at 18:18
  • I'm not looking to prevent the lithium cells charging beyond their designed capacity as discussed in the accepted solution to the post "Battery Full Alert", rather to prevent charing past a point significantly below their safe design capacity. – Scottmeup Apr 20 '18 at 12:04
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In short, no. Well, at least not without changing the SMC Firmware.

The SMC (System Management Controller) is responsible for controlling a range of power-related functions (e.g. controlling fans, reading and responding to sensors, controlling temperature levels, the battery, etc). This is not something you want to mess with.

In terms of battery swelling, there are many factors that contribute to causing this and one of those factors is time. For example, I was responsible for a small fleet of MacBookPro5,1 models being used by five staff members, all of whom had two batteries (so they could hot swap them as required). All of these batteries swelled over time, despite the fact these laptops were used off AC Power for most of the day five days a week. The fact these devices were not kept at 100% charge made no difference whatsoever!

In a nutshell, if you're happy using FruitJuice then keep doing that. But trying to force the SMC (or circumvent its function) is likely to cause you more problems than its worth.

  • Thanks for the great reply. I was hoping there might be a solution for charging similar to what smcFanControl does for fan speed. – Scottmeup Apr 19 '18 at 8:38
  • @Scottmeup - smcFanControl is not a "solution" to anything. – Allan Apr 19 '18 at 18:16
  • Don't recall saying it was, but good to know all the same ;) – Scottmeup Apr 20 '18 at 11:21
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The new batteries are so far, far, far superior to the old ones I would say you are not going to achieve any measurable or meaningful benefit from micromanaging the charge algorithm.

Apple has fundamentally changed the top off charge algorithm and has multiple cells so even at 95% charge one cell can be resting with the rest topped off.

Any Apple battery rated at 1000 charge cycles is in the same class if it’s 2010 or later model year.

Even if you could change the charge, I wouldn’t since Apple engineering likely did a better job than we could trying to modulate the charge levels to support long life of the battery.

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You could do it with hardware. An arduino, a relay and some scripting would do it.

or just a bluetooth/wifi controlled power plug.

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