It did not move easily when I tried to pull it back into place with my fingernail, leading me to believe it had been that way for some time. On the upper top side of the charge controller, I noticed a broken chip capacitor. However, I would not expect this quirk, a result of poor assembly technique, to contribute to the battery pack shutting down. Air (especially dead air space) is a great insulator, after all. In the high power R/C world, this sensor would be plastered down or glued to the center of a battery pack. One thing that I noticed right away was that the temperature sensor was not in physical contact with the cell it was taped to. A minimal amount of high temperature PI (polyimide) tape is used for a good part of the assembly. Along the side/end of the battery you can see a temperature sensor (later determined to be a NTC thermistor measuring 7kΩ at ~20☌ and 9kΩ against an ice cube). (The red and black electrical probe is only there to hold the blue tape up for the picture.) The yellow and white wires are connected between the cells for individual cell balancing and monitoring.Ĭharge controller (and over discharge protection?)īefore I tore into the battery pack, I wanted to get a few pictures of the electronics and wiring.
#MACBOOK PRO ACTIVITY MONITOR SPIKES WHEN ON BQATTERY POWER SERIES#
The photo above shows the simple series wiring of the battery pack, referred to as a “3S” pack in the R/C world. (Don’t know what she does to them, but my daughter’s were razor sharp.) Once started with a butter knife, most of the plastic spot welds were broken with upwards of 20 fingernails. Family, holidays, and work be damned Christmas was still 12 days away, yet I had a toy I could play with NOW!ĭue to cheap plastic welding, the battery pack opened fairly easily. Take it away, Lee!ĭue to my excitement upon receiving Brian’s battery, like a kid on Christmas morning, I had to open it up and get started that same evening. I’ve reproduced it all below in Lee’s own words, again only lightly edited by yours truly. Lee kept me updated via a series of email exchanges as his analysis progressed, concluding with a 23-slide PowerPoint deck that combined photos and often-hilarious (at least I think so!) commentary and also showcased the contributions of his daughter. With introductions out of the way, let’s get to the meat of the writeup. Founded in 1934, Indium has global technical support and factories located in China, Malaysia, Singapore, South Korea, the United Kingdom, and the USA. Products include solders, and fluxes brazes thermal interface materials sputtering targets indium, gallium, germanium, and tin metals and inorganic compounds and NanoFoil®. Indium Corporation is a premier materials supplier to the global electronics, semiconductor, thin film, thermal management, and solar markets.
In his off time, he enjoys building and flying R/C aircraft (and recently, boats), cycling and (despite his age) participating in watersports activities. When he is not in the lab formulating polymer products for the electronics industry, he wears the hat of “data acquisition guru” for the R&D department. Lee Kresge is a Research Chemist working for the Indium Corporation. Before documenting what Lee found from his detailed (and creative) analysis, however, I’ll begin by telling you a bit about both Lee and his company, in his own words (lightly edited by yours truly for grammar, clarity, etc.). Lee even picked up the one-way shipping tab! I was happy to take him up on his generous offer, the results of which (complete with photos) I’ll detail in this post. If your wife’s MBP battery is destined for nowhere other than the trash can (or, recycling), I could take a look at it for you if you could get it to me. And shortly thereafter, I received an email from research chemist (and off-hours radio-controlled airplane-and-boat enthusiast) Lee Kresge of Indium Corporation: This behavior wasn’t something I’d encountered before, so I reached out to the readership for root-cause suggestions.
When the battery full-charge percentage dropped to 90%, the system would abruptly shut down. Last November, I documented my troubles with a replacement battery I’d installed in my wife’s mid-2010 model 15″ MacBook Pro laptop earlier that year.
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