Its a standard setup. You can get the battery management PCBs from FastTeck. The board the writer refers to a turning off the cells was a faulty unit, I hit one once. But the "square" PCBs are better as they will give a slow death rather than an abrupt switch off. When assembled the PCBs will be in an off state anyway until connected to a charger. This is because they are used in laptops and phones etc and will be in the off state for safe shipping. You will have all bought something like that and believed the battery to be flat. It isn't, its just electronically disconnected until connected to a charger.
The writer also appears to be using high capacity 3400 mAh cells which are actually better than the standard battery packs (2600 mAh cells) which are an off the shelf item that uses lower capacity cells, now its 3500 mAh.
Only issue with doing this, apart from knowing how to use a soldering iron etc, is the lamps. If the manual warns to only use their batteries, its wise to do so, if it says OK for other battery types subject to voltage, it would be OK to make up the DIY power packs.
Above is what I originally wrote, now I am editing it.
If he is using 18650 battery holders rather than soldering to the cells, forget it!
The PCB disconnect was due to a knock causing a temporary circuit break to the PCB, this will cause a switch off until connected to a charger.
We all know about knocks and bangs underground don't we.
Unless you feel competent to solder direct to the cells, and it does not destroy them, several large manufacturers are doing this. forget the idea.