Avoiding battery overheating when using MBP in the sun

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Level 1

24 points

Avoiding battery overheating when using MBP in the sun

Are there any ways to keep a MBP battery cool when using it outside in the sun? Or should I just not worry about it?

Today I was sat on my balcony enjoying the Mediterranean sun using my 2014 MBP when Coconut Battery popped up with a notification warning me that my battery was beginning to overheat and that damage could result. It was reporting a temperature of 35.5 C.

So I opened up Macs Fan Control and switched from monitoring the CPU temperature to monitoring the battery temperature. However I get wildly different readings from the 3 battery sensors that MFC monitors compared with Coconut - sometimes the former shows more than the latter, other times the opposite. The hottest either of them registered was 38 C. I tried cooling it by setting MFC to max the fans out when the battery sensor read over 35 C but I'm not sure it made much difference - and having looked at MBP teardowns I know the battery is nowhere near the CPU fan.

I'll be wanting to use my MBP outside more as we move into the heat of summer but I want to avoid battery damage. There's loads of stuff online about MBP CPUs getting hot - something which I think is a silly non-issue - but batteries are definitely more vulnerable to heat than silicon. Any tips anyone?

MacBook Pro with Retina display, OS X Yosemite (10.10.2)

Posted on Apr 12, 2015 9:30 AM

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Answer 1

OGELTHORPE

Level 9

57,305 points

Apr 12, 2015 10:12 AM in response to Fean0r

Any time the battery temperature exceeds 30°c, the battery is beginning to be harmed. Find a cooler place to use the MBP or be prepared to purchase a replacement battery sooner than expected.

Ciao.

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Answer 2

Fean0r Author

Level 1

24 points

Apr 13, 2015 11:33 AM in response to OGELTHORPE

As low as 30 C? I've been watching my battery temperature under normal use indoors at room ambient temperature and it sits at 34C most of the time, according to the sensors monitored by Macs Fan Control. I've not been watching Coconut Battery so much but that's also reporting 33.8 C.

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Answer 3

OGELTHORPE

Level 9

57,305 points

Apr 13, 2015 11:51 AM in response to Fean0r

Here is a reputable source indicating as such:

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batterie s

Read the paragraph before the temperature chart.

Ciao.

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Answer 4

Fean0r Author

Level 1

24 points

Apr 16, 2015 11:31 PM in response to OGELTHORPE

Thanks, I'm familiar with Battery University. I read a lot of their stuff in some detail a while back when it was quite out of date - I see they've just updated that article so I need to reread it more thoroughly but the only metrics I can see about temperature on that particular page are about battery storage:

"A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion, a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling."

It doesn't seem to say anything about the a battery becoming damaged by occasionally heating itself to the mid-high 30s C for relatively short periods as a result of normal use in slightly warmer ambient temperatures.

I've since had more Coconut battery warnings for similar temperatures while using the MBP indoors on my lap at room temperature, and others while the MBP was on a table charging and running some background tasks. As I write this sat in my bedroom the battery is reading 33 C - just 2 C away from the threshhold when the warnings start. This is all well within normal use and should be designed into the unit's normal operating temperatures so I'm not going to give much credence to Coconut Battery's warnings now I don't think.

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