Correction to my last post, I just saw a youtube video about the multi charger. It does charge sequentially, but slightly different than the offering from DJI. It will charge a battery to 80%, then move on to the next battery while still topping up the first one simultaneously. It will use your existing charger "brick" and the lead from that charger plugs into the multi charger at the bottom of the base. The reason for sequential charging is because the OEM charger only puts out so many watts of power. To run 4 batteries in parallel would actually take longer than running them one at a time. Not to mention the battery chemistry behind Li-Po has an optimal current to charge so running far too low of a current would cause more harm than good. On a final note, they could theoretically just include a new AC/DC Converter that outputs far higher wattage to charge all 4 at the same time, but I imagine the size of that would grow. Maybe someone that has one of those aftermarket modded DJI Mavic chargers could chime in and let us know if that charger will charge all 4 batteries in the same time as the OEM Charger. If it takes much longer than it's merely splitting the current 4 ways in parallel. Looking at the photo of it online the case does state the same output current as the OEM charger so without me having one, I could only assume this is the case.