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 Series

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.

Really good product. Delivered without damage and the build quality of Anker is great. Not too bulky! It gets heated a bit when overused, but the magnets are very strong! It always says slow charger while using this! Not even optimal speeds is concerning, but it saves the phone from shutting down.

UPDATE 3/11/2026 - Anker absolutely honored their commitment to their product and issued me a replacement. They were quick to respond and to mitigate the issue I had with their product. Thank you ANKER!! I’m a huge Anker fan and a loyal consumer of their products, so this is the first time I’ve encountered an issue with one of their products. The charging itself works fine, the problem is that the magnetic charger gets very hot, which disrupts charging until the temperature drops. I have another brand with the same specs that doesn’t have this issue.​​​​​​​​​​​​​​​​

A very good power bank, pretty light and easy to carry. It stick very well to the phone and it charge it pretty fast!

So handy to use if you forget your charging cord..it seems to charge phone quickly..you do have to charge the portable charger between each phnoe charging..for me it’s not a big deal..

This is a great little charger. It has been an essential part of my daily routine since I bought it in mid 2024. If I put it on my phone before it dropped below 40% it would get me back to 100%. The size of it was slim enough that it didn’t bother me while using the phone. Thick for a pocket when attached so I just kept it out of my pocket. Easy fix. That said, a few days ago I went to put it on my phone and it had swollen and would sit flat on the back of the phone. I’ve got other batteries that have lasted much longer. I didn’t do anything different than I have every other day. I guess it just… died. Honestly I’ll probably try another brand. I feel like it should have lasted longer. That may or may not be a reasonable expectation with something like this but that’s where I’m at right now. Good luck if you decide to try it out.

It works great. Only good for one full charge. Like the slim fit.

Lo compré para mi mujer y está muy contenta con la batería externa. Trae suficiente carga para recargar su iPhone una vez (y sobrarle algo). Al ser pequeño y con MagSafe, pues cumple con todo. Buena calidad de construcción

Product is light weight and slimmest powerbank in the market. material feels very premium. Magnet has good power to hold the mobile.

Amazing and I love the colour. I can even use it as a wire charger for my AirPods and not worry about it sliding off the patch it has magnets

Great MagSafe charger from Anker

Although its limited to 7.5W of wireless charge, its very convenient for that extra boost to keep going. Sure there's heat, but that's basic physics. Anyone looking for a minimalistic EDC needs this. The silicon backing that mates to your phone provides good contact and the magnet is strong. Slim design makes holding your phone and the power bank very comfortable. Even on an S24+, the battery works well. Looking forward to trying out the 10mAh slim wireless power bank.