This thread is all about charging. To charge or not to charge. I did a preliminary test using a battery pack with two charging ports. One port provides 1 amp while the other port provides 2.1 amp. The supplied Surface 3 Charger provides 2.5 amps as labeled. Note this was done over a short period of time, more extensive testing is required. With the internal battery starting at 63% and my battery pack starting at 95 % I connected the cable to the 1A port. during a period of varying usage the Surface indicated it was at times charging and other times not charging although allways indicated it was connected. Throughout the time the internal battery remained at 63% while the battery pack dropped to 75%. Once I pressed the Surface power button the rate of drain on the battery pack seemed to stop or at least slow significantly. Note this was done over a short period of time. After a few minutes I pressed the Surface Power button again and recorded 65% charge on the internal battery. Then I switched the cable to the 2.1 A port. We are now at 66% charge on internal and 72% on external battery. I kicked off a benchmark test to generate load and we immediately switched to not charging and internal battery level dropped to 64% over the duration of the test. This was a little unexpected and it seems the 2.1 A port generally refused to charge as the external battery level never dropped. Perhaps something flakey there, switched cables, now seeing power level drop on ext batt so rerunning the test again. Internal batt at 63%. This time again we see status switching from charging to not charging and ext batt level dropping down to 63% while int level increased to 64%. Another run of the test and initially we are NOT charging... after some futzing around it's charging and holding the internal battery at 63%. Clearly something strange or maybe its the magical 63%. need to spend more time on this. This is also a new battery pack, could be a problem with it. I was using this because it has it's own power meter so it was convenient in that respect. Update1: Connected to the charger the Surface 3 only draws 1.3 A and its only getting 1.1 amp from the battery packs (I tried two of them) but they ramp down after about 5 minutes and then shutoff for a while so they appear to not be continuous duty cycle devices, at least the MS charger keeps charging at the 1.3A rate. This was observed while the Surface 3 was on but idle.