Thread bump... I have a P3A and had an opportunity this month to grab a P3P's 100 Watt charger for a rather paltry sum of money, so I jumped on it. I'm gonna speak about my observations so far as well as comment on a few prior posts.
So yeah, my P3A's stock charger is rated for [up to -- more on that in a moment] 57 Watts and the P3P charger is rated for 100 Watts. If the battery pack's integral charging circuit was designed to draw the entire 100 Watts, that would drop charge time over 40%, right? Well, apparently not. My pack (yeah, only one right now but that's being fixed today) charges from 10% in upwards in 75-80 minutes and with the 100 Watt charger last night, it still took 58 minutes. So the good news it's still around a 25% improvement, which helps when you're in a hurry and losing daylight and patience.
The bad news is that 100 Watt P3P brick is HEAVY. Those inclined to think it's just DJI's budget decision to use a 57 Watt brick on the P3S/P3A may not be entirely wrong but carrying around the extra weight might also be something that was only tolerated by the higher-end buyers in focus groups. Just putting that out there.
Given how slowly the remote controller charges with respect to the size of its battery, I can't imagine how the 100 Watt charger could possibly improve charging time. But those who quickly dismiss the RC's typical battery capacity should also remember that if your tablet or phone is low on battery, the RC may wind up supplying charging power!
I should put an ammeter between the charger and the pack next time, to get some real numbers. DJI's insistence that customers should not simultaneously charge the RC and a battery pack, especially if you have a 100 Watt charger, from an electrical engineering point of view seems silly in light of the 15% gap in power capacity versus draw that I'm seeing. With the 57 Watt brick it is conceivable that the total power draw could be bumping up against the limit of the brick and might wear it out prematurely, or could alter the charging curve of the batteries and result in less than optimal performance over time. It is possible that DJI believes customers won't distinguish between the different chargers, and chooses to play it safe.
Cool-downs... I think think there's anything hugely wrong with the bag in a bucket of ice approach if the bag is sealed well. Hanging the battery in front of a car/truck AC vent for five minutes works quickly enough. I have been known to use nearby convenience store refrigeration. Don't freeze the battery! It only takes a couple of minutes to cool down sufficiently. Here's the thing, though... the resulting condensation from rapid temperature changes could wind up being harmful to the electronics after a while. The question is whether condensation screws things up before the batteries themselves wear out.
About electricity... A Watt is a measurement of power. With a power supply, that number is the amount of power that the unit is able to supply. With a load device that number is the amount of power that the device requires from the power source. A traditional 100 Watt light bulb for example, consumes 100 Watts during operation but the wall socket you plug the lamp into is probably capable of supplying upwards of 1800 Watts.
So the P3P's power supply doesn't "put out" 100 Watts the moment you plug it in. It puts out 17.5 Volts (according to the markings). It is rated to reliably put out that voltage, give or take some design tolerance, at up to a 5.7 Ampere current demand from the attached load. 17.5 Volts x 5.7 Amps is 99.75 (nee 100) Watts. The P3S/P3A supply is rated 17.4 Volts x 3.3 Amps = 57.42 Watts. Note, I'm seeing 17.41 Volts coming out of that P3P supply with no load.
PS, these chargers (which are just run of the mill "switching" type power supplies) work just fine even on cheapo 12V car inverters. For best results I recommend choosing an inverter with at least 25% more capacity than you plan to draw.
