Anker 621 Magnetic Portable Charger (MagGo), 5,000mAh Wireless Power Bank with USB-C Cable, Magsafe-Compatible Battery Pack for iPhone 16/15/14/13/12 SeriesClimatePartner certified

This was my first Magsafe battery. I had some older Qi wireless chargers and was familiar with heating issues. But these were older and lower power. Without the Magsafe feature, they were finicky and fussy and didn't properly fit around camera lens protrusions. I barely used these devices.This Anker 621 has a lot of promise. The Magsafe feature locks tight and the dimensions do not interfere with the camera protrusions, even with a case on the phone. It's compact and slim, and most importantly, does not require wires. It can be easily carried in a backpack or pocket without an accessory bag for wires and cables.When I first unpacked the battery, I fully charged with with a USB-C PD charger. It charged at 1A/5V. I used it to inductively charge my iPhone 14 Pro intermittently over the next few days. After about 10% charge, I determined the heat buildup to be intolerable. Therefore, I only used the pack intermittently. That worked fine for me over several days. When the battery was empty, it took 20Wh to fully charge. The battery was advertised for 5000mAh, which is impossible to measure without disassembling the unit. However, we can calculate 20Wh / 5V / 0.9 = 4400mAh (where 0.9 is the efficiency of the voltage converter for USB). This is below advertised capacity, but there’s a lot of assumptions in the conversion.Then I used a USB-C cable to charge my iPad Mini. It transferred 14.8Wh at about 9 Watts before exhausting. The round-trip efficiency was high, because recharging took 14.8Wh to fully recharge. I suspect I didn’t get the full 20Wh capacity with the iPad because the higher charge demand choked the battery before it could get fully empty.Using the inductive charge mode, both devices get hot relatively quickly. The switching power electronics get particularly hot. I can easily feel where the transistor is located beneath the plastic shell. The inductive transmitter loop gets warm on the battery and the receiver loop gets warm on the phone. Lithium-ion batteries degrade proportionally to temperature (the Arrhenius relationship), accelerating +25% degradation rate for every 10C, this is bad for the phone.In summary,• The battery delivers 20Wh of energy. If using inductive (Qi and Magsafe), much of the energy is converted to heat, so perhaps only 10-15Wh is actually delivered to the battery.• If using high-current devices using a charge cable, such as an iPad, the high current chokes the battery a bit early, stopping at 15Wh.• My back-of-the-envelope calculation shows 4400mAh vs. rated 5000mAh. I suspect the battery is not delivering rated capacity. Anker should be rating these batteries in Joules (watt-hours) instead of Coulombs (ampere-hours).• Inductive charging is inefficient, losing a quarter to half of energy to heat. This is not Anker’s fault but a result of real-world physics. With my iPhone 14 Pro, I saw about 10C rise per 10% of battery charge. I never let it progress beyond this point.• Lithium-ion batteries accelerate aging degradation due to the Arrhenius relationship about +25% per 10C temperature rise. Therefore, prolonged use of inductive charging will ultimately age your battery prematurely.• This battery is very worthwhile because I don’t have to carry an accessory kit with wires to use. Just slap it on the back of the phone and go. Plus, if frees the connector to use with wired headsets when using.

Just received this to replace another same type battery but that one would go on then just shut off for no apparent reason. I do have an IP-12 and i use a pretty heavy case so i wasn't sure how these type of batteries were going to work.I installed the metal ring on back of case and as it held battery ok it just wouldn't charge. So i bought this Anker to try it as i do like Anker batteries. Well right away it stuck right to my case and immediately started to charge. I was still skeptical. I just waiting to see if it shuts off and it never really did. Yes it gets warm just like the other battery, but that's the characteristic of this type of charging. But I have to tell you this thing grips much better than the other battery I had, maybe it has something to do with being a MagSafe battery I don't know that's why I wanted to try the Anker as its not a Magsafe but a Maggo and boast that it has a much stronger magnet, and I can Contest to that. It's not the fastest charger but it does charge. It is probably taking me an hour and a half hour to go from 60% to 95% for me that's OK. It's meant to be more of a rescue battery to basically get you through the rest of your day, my phone that has relatively small battery. This battery probably would charge it fully but The newer phones have larger batteries. This probably will maybe get you 80% which is just enough to get you through the rest of your day.Yes, heat is a factor and some people complain about it and some people understand It's a necessary phenomenon in this kind of charging, this case with the heat temperature gun i saw134 degrees at its peak but it does go thru cycles of heat and cool as internal thermostat kicks in. To me thats a minor inconvenience, but it does not heat up your phone. The heat stays within the battery itself and it does not radiate to your phone. So far so good i using it now to write this and as the charge percent is not rising as fast as it did when I wasn't using the phone. It's basically holding the percent at one particular spot right now.So in closing, if you have a heavy duty case, try it, it might work get the rings and put them on the back of your case and see what happens. My rings came with a template which is not easy to use with a heavier case so what I did is I attach the ring to the actual battery And I moved the battery on the back of the case where I found a nice spot where the phone always went on charge every time I hit that spot and then I remove the plastic on the ring went back to push the battery down on that spot removed it push the ring down by hand make sure it was good And that's it, sometimes that's more accurate than using a template. I do agree that the thickness of the case plays a big roll in whether this will work or not, but what do you got to lose if it doesn't work you can return the battery or buy a new case that's thinner and will work better.

This product is amazing. Compact but reliably chargers the phone quickly and enough. Can get a little hot if you use the phone while charging (duh) but the MagSafe ability is so great. I can shake it like crazy and even throw it across a room and it stays on. Not to mention, this has saved me on a number of occasions. Yes it doesn’t hold much, but it’s compact, effective, and easy

It’s a great battery so far it’s a nice replacement from my mophie one but it has some negatives from my mophie one but it has more positivesPros:-it’s very slim-it charges 5w-7.5w wirelessly-Very strong magnets-very strong usbc port-Doesn’t interact with the camera bump on my 13 mini-really nice materials and build quality-it has pass through charging (when plugged in it can charge itself and my phone at the same time-it has a rubber type material so on the non matte back iPhones it will grip on more making it harder to slide offCons:-it charges very slow im using a 45w ac adapter and it seems to be charging at 20w my mophie one can charge at 45w for 2 hour charging time the anker one has been on the charger for 2 hours and just got to the 3rd led-it gets warm when charging my mini but if you have a bigger phone your phone won’t get as hot when chargingMisc:-it turns on automatic my when i put it on the back of my phone but before that I can turn it on with the button and hold the button so it won’t turn on until I want to use it-the button is very clicks and solid-the leds are bright enough but hard to see outdoors-it doesn’t have the official MagSafe charging animation

Allows you to charge your phone one and a half times. Charges your phone very quick! Good weight and size. The style is fine.