I just got a 65 watt USB C charger (this one, but I'm guessing any will work), and wow what a difference versus using a phone charger power source. I think the stock battery charger just charged my stock battery in 15 minutes... That's approximate and I'll try to time it exactly next time. But that's a whole lot better than I was getting, which was about an hour per battery.
I read somewhere that the stock DJI battery charger uses a max of 30 watts, can anyone confirm that? In other words no reason to use a charger more powerful than 30 watts?
This link says the capacity of the stock Pro 3 Mini battery is 17.28 watt hours. So 30 watts should charge them in just over a half an hour. It seems like I just charged them faster than that, but I'll confirm.

And I'm wondering about damaging the batteries. I think this is how to calculate the C-rate of this amount of charging:

30 watt charging = 8.4 max charging volts of the battery * 3.5 amps. So we're charging at about 3500mA  / 2400 mAh battery capacity = ~1.5C rate of charge. I see varying C-rate numbers for healthy charging of various lithium battery chemistries, but 1.5C does seem a bit high. Thoughts on that?  

Also I ordered this battery charger so I have a second charging station, since it was cheap enough:

https://www.amazon.com/dp/B0BLYVJY3R

Any thoughts on it? Any others people would recommend?

And wondering what other tricks people have found for keeping their drones charged up. Normally three batteries of fly time is enough for me, but I'm trying to work out a good system for those rare days when something spectacular is happening and I really need to keep flying.

my strategy is to buy a bunch of batteries, enough to last me for whatever i need to do.  that usually means 5-8 batteries per drone.  that way you dont have to worry about different chargers and rates and sources, etc.  if i take 2 or 3 drones with me, it's literally impossible to be forced to leave because i'm out of battery power.

If you use a charger higher than 30 watts the device you're charging will just not take the extra power,   a good way to think about it is volts are pushed and current is pulled.