Honestly, I'm not ignoring any information. I do believe his "recommendations" are good in general, but also do not believe that it applies to every single li-ion battery charging system out there. It definitely does not apply to every single cell phone or laptop charging circuitry. I don't have the studies to prove it, but I'm fairly confident that 99% of the cell phone user base do not turn off their phones while charging and we're not seeing daily reports of exploding phones. Even the actual reports of catastrophic failures have been very rare and generally attributed to physically damaged or poor quality cells / chargers. Some or perhaps many of these new power banks utilize some of the same circuits used in those phones and do not apply these "mini cycles" that you're so worried about. If you're truly want to adhear to every recommendation to the letter, then you probably shouldn't even charge any of your li-ion power devices above 85% so they are never stressed or subjected to the potential of a thermal runaway.
The way I read his statement regarding pass through charging of portable devices in cradles, is that he was referring to old cell phones, hand held radios and other devices which have charging contacts on the outside of the case/battery. In those devices, the charging circuit is outside of the device and it would be attempting to charge the battery while the device is actively drawing power from the battery. This is not the case with most of today's devices, as the charging electronics are integrated into the device itself. The "charger" is just a dumb current source and the device itself decides if and when it needs to charge the battery. There is no possibility of damaging the charging or monitoring circuits, which by the way is the same thing in today's devices, when used while charging.
Personally, I'm not all that concerned with pass through charging of power banks. I've taken apart my power banks and have actually measured the charging voltage at the battery terminals. Some are designed to be conservative and don't even let the cells reach 4.20V. Also there have been technology improvements since that article was published, such as 4.35V cells and better / cheaper / smarter charging ICs, developed specifically due to the exponential growth of cell phones, tablets and other portable electronics. I think few if any of those devices you purchase today warn against using them while charging. They may recommend not doing so to improve charging speed or battery life, but nothing that even hints at the potential of thermal runaway from normal use. If the likelyhood of that happening were more than even remote, you can bet the lawyers would have strongly worded warnings and require safety circuits to disable such operation, not necessarily for user safety, but rather to prevent lawsuits. Does that mean that the entire industry is wrong and putting explosive devices in people's homes? No, it's just that everything changes and technology is usually the quickest of all. I have no doubt Mr Buchmann is an expert in the field, but I also believe that specific recommendation does not apply every single li-ion system design or take into account advancements that have been made since the article was published.
Really, the only thing I wanted to point out was that a blanket statement that pass through charging on any li-ion device is always bad / dangerous based solely on that article is patently false. It's also quite easy for just about anyone who knows how to use a DMM to test and verify for themselves whether their device can do this correctly. Just measure the cell voltage while connected to a charger and a small load simultaneously and see if it rapidly oscillates up and down or never reaches the full charge voltage. If all it does is slowly drop to the lower charging voltage threshold, then rise again to the full voltage as charging kicks in, then it's all good. This is the same thing it would do whether a load was connected or not. As for vibration and shock being an issue, honestly, the type of vibration experienced in a car is insignificant compared to what they experience in the RC world and other applications. And your example of the pack falling off a seat due to an extreme stop would be an example of damage that could occur to any device and pass through charging would not stress it any more than when you plug it in manually to charge. I should also think that people who are considering using their power banks in this way would have the unit secured in some way, if nothing else, to prevent the cables from being torn away.
If you really want to warn against something, then it might be leaving the power bank connected to a charger continuously. Even then, the only downside is the possibility of reduced battery lifetime, but I'm of the opinion that it's negligible based on my own personal experiences. What's more important is ensuring that the batteries are not exposed to prolonged high temperatures while charging. This should not be a big issue if the batteries are in the cabin, not obstructed from airflow and only charging when the vehicle is running, which is how I would have it wired anyway.
What I would recommend to everyone who is thinking about using their power banks in this specific application is to read the information for themselves and form their own conclusions based on at least some testing, not just what they read off some website or forum.
KuoH
