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Samsung has called a halt to all sales and exchanges of the Note7, suggesting they have not got to the bottom of the battery fire problem. I imagine Apple is popping champagne corks.
I wonder if Samsung took the concept of fast battery charging a bit too far with the Note 7, because my Note 4 has fast charging and it's just an incredible feature - a 50% charge in just 30 minutes for a 3220 mAh battery.
I wonder if Samsung took the concept of fast battery charging a bit too far with the Note 7, because my Note 4 has fast charging and it's just an incredible feature - a 50% charge in just 30 minutes for a 3220 mAh battery.
It's possible the fast charging feature went wrong. But the replacement phones caught on fire were not in the charging mode when the incidents happened.
One of the difficulty for me to understand is the Note 7 can start burning even when it's not in the charging mode. For example there is a new incident in Houston:
Initially Samsung blamed the bad battery made by non-Samsung suppliers was the cause even Samsung itself also makes batteries. But now the new replacement phones have caught fire. It makes me wonder if Samsung is telling the truth and if the battery is really the only culprit.
I like to say that more than one thing has to go wrong for a plane to crash. If you look at any plane crash you can see that 3 or more things went wrong, leading to disaster. If one thing goes wrong, there is margin and the result is not usually bad. Same goes for the Deepwater Horizon. Side note: the technical details about the failures (yes plural) in the blowout protector are fascinating. More than one thing went wrong leading to a chain of events that caused the blow out.
I'm betting that the same principle applies here. If it was just the battery alone, then a new battery would solve the problem. It seems they tried to use a new vendor, but alas, there are still problems. The charging circuit is crucial in protecting the battery from over heating. I'd bet there is more than one actual problem and we are seeing the result in these incidents. My guess is an interaction between the battery and charge controller that could have been aggravated by any number of other issues such as assembly, etc.
Modern batteries dislike mechanical stress and thermal stress. Maybe the manufacturing process of the Note7 is creating some mechanical stress at some point that makes the battery fragile. And for sure, there are more than 1 source of thermal stress when using a phone.
Fast charging is one but not all phones were charging when they exploded. The other major source of heat in a phone is the CPU. Samsung may never tell us but I would not be surprised if something is going wrong in the CPU/GPU making it overheat. I've had this on many phones of all brands. Sometimes, without any obvious reason, the CPU gets really hot even if not much is going on. I guess the variable clock rate and the big-little arrangements are not 100% perfect. If the battery has not been stressed, then it's not an issue and everything goes back to normal a few seconds later. If the battery is fragile, maybe this sudden heat is enough to get into trouble. As @Tom Simon said, one cause is not enough and the Note 7 faces a combination of causes. In this case, CPU + Battery. This is only a guess, based on very vague reports. Anyway, this would explain why the change of battery supplier did not fix the issue. It's hard for Samsung to blame the CPU because it could open several other cans of worms: Samsung vs Qualcomm, Samsung vs TSMC, ... Potentially very ugly. Better blame the battery. Sorry if this sounds like a conspiracy theory. One thing is sure, the battery is not the only source of the Note 7 debacle and Samsung isn't very forthcoming to give us a credible explanation.
I think there are at least two possible reasons to explain why so far Samsung hasn't publicly disclose the true cause:
1. The root cause is too complicated and even Samsung can't figure it out right now. I know it's hard to believe considering Samsung mobile division is a US$25 billion business (2015).
2. The root cause is very embarrassing and it can damage Samsung or its major partner's reputation. And Samsung was hoping to let the crisis to quiet down by itself and trying to limit the negative impact to just one model, Note 7.
