Review: ROMOSS Apple Watch 3,250mAh Portable Charger

ROMOSS Apple Watch 3,250mAh Portable Charger











  • Features two ports, one for a Apple Watch Magnetic charger and the other one is for charging your smartphone from
  • Has a very small form factor


  • Does not come with a Apple Watch Magnetic charging cable
  • Has a outer plastic shell that is quite thin

For the most part, many of the power banks on the market don’t come apart, they’re all put together and all you have to is just plug-in a charging cable to use them. However, for this ROMOSS portable charger that we’re reviewing, it actually does come apart because you have to place an Apple Watch magnetic charging cable into it, and that way, it becomes an Apple Watch portable charger. So let’s take a closer look at what a power bank that comes apart is like and see if it’s worth getting.


Power Capacity:

The initial power capacity of this portable charger is 3,250mAh, so it’s definitely a low capacity power bank no matter how you look at it but that’s okay as the purpose of this charger is really meant for charging an Apple Watch and possibly a smartphone.

3.7 x 3,250 = 12,025 / 5 = 2,405

DevicesROMOSS Apple Watch 3,250mAh Portable Charger (Output Capacity = 2,400mAh)Device CapacityROMOSS Apple Watch 3,250mAh Portable Charger Left Over Capacity after One Charge

# of Full Charges for the Device
Apple Watch2,400mAh250mAh2,150mAh Left Over Capacity

9.6 Full Charges
Apple Watch Series 32,400mAh279mAh2,121mAh Left Over Capacity

8.6 Full Charges
iPhone 7 Plus2,400mAh2,900mAh0mAh

You need 500mAh more for a full recharge
iPhone 82,400mAh1,821mAh579mAh Left Over Capacity

1.3 Full Charges
iPhone 8 Plus2,400mAh2,691mAh0mAh

You need 291mAh more for a full recharge
iPhone X2,400mAh2,716mAh0mAh

You need 316mAh more for a full recharge

The actual amount of output capacity that you’re really able to use is about 2,400mAh. If you take into account the average capacity of most Apple Watches, which is 250mAh, or 279mAh for the Apple Watch Series 3, then you can about 8 full charges for the watch. Not bad at all and this just goes to show that even though this is a mini power bank you’re still able to get many full charges as the Apple Watch itself has a low battery.

For charging smartphones, well, this power bank does have a USB port that you can charge smartphones with but depending on what phone your charging, you’re able to get a single full charge from the capacity or a nearly full charge. Of course, if you’re getting this power bank then you likely own an iPhone then you are able to get a full charge for most iPhones on the market. That said, it’s the larger iPhones such as iPhone Plus models and the iPhone X, that are not able to charge to their full power with the 2,405mAh output capacity that this charger has.

So if you’re charging a smartphone with this power bank then you can expect it to deplete the entire power capacity.

Output Charging:

There are actually two charging ports on this power bank. One is hidden away in the center of the power bank that’s really meant to be used with your Apple Watch magnetic charger. The other charging port is on the side of the power bank that you can easily see.

Something important to know is that this power bank does not come with a magnetic charging cable and you have to supply your own, that’s basically one main reason that this power bank is low-priced.

Both of the ports on this charger have a 5V/1.0A charging speed, so you’re able to charge your Apple Watch at its max charging speed. If you’re charging a smartphone with the other port, then you can expect a slow charging speed, as most smartphones on the market are able to charge faster than 1 Amp now.

Input Charging:

Recharging for this power bank is done through the Micro-USB input port and it has a 5V/2.0A recharging speed. So if you want to recharge this power bank at its max charging speed then we recommend using a 2 Amp USB wall charger. The use of a 2 Amp recharging speed is not very common when it comes to mini power banks, as the input speed is usually 1 Amp, as well.


Size and Weight:

The size of this power bank is small and you’ll have no problems in the portability department. As the charger has a length of 4.7 inches, and a width/thickness of 1.3 inches. The weight of the power bank is 3.8 Ounces. So it’s not only small enough to fit into a pocket but when you place this power bank into a pocket you can easily forget that it’s there, just because of how lightweight it is.

Functional Components:

There are two main parts to this ROMOSS power bank. There’s the inner part, which is basically the power bank itself, and then there’s the outer shell piece.

The inner part of the power bank has the two USB-A ports, with one USB-A port being in the center where you connect a Magnetic charger and the outer port is for charging smartphones. The inner piece of the power bank actually has grooves set-up so that you can wrap your magnetic charging cable around it and then the circular end in the spacing.

Once that’s done, you can then place the outer shell onto the main piece. On the end with the outer USB-A port is where you’ll also find the Micro-USB input port, the power button that needs to be pressed to start charging, and also a single LED light that turns on to indicate that a device is charging.

There’s only a single LED light on this power bank which is something that we found strange as most power banks have multiple LED lights.


Structure and Material:

The build quality of this ROMOSS power bank is okay, but nothing impressive. The entire outer shell of the power bank is made of plastic, so it’s a good charger for every-day use but it’s not rugged and would definitely be careful not to drop the charger.


On the tech side, ROMOSS Apple Watch charger has no problems with heat, even if you’re charging two devices at once and that’s likely because each port is only able to output 5V/1.0A, and as a result, that does not generate too much heat at all.


The reliability of this power bank fits well for those that own an Apple Watch and want to have a portable charger that they can use to charge their watch while they’re out and about. If you’re looking forward to also charging a smartphone with this power bank and at the same time having enough power capacity to charge an Apple Watch, well, there’s not much capacity to use as this is a very low capacity charger, to begin with.

Just know that charging an iPhone and an Apple Watch at the same time will drain the capacity very quickly.



It has a very low power capacity that can also be useful for charging a smartphone at least once or likely even less. That said, if you’re only using this power bank for charging an Apple Watch then that can yield a lot more charges and it’s basically the real purpose for this power bank.


The size of this charger is very small and it’s a low profile that it’s barely noticeable in a pocket. It’s also very easy to install your Apple Watch Magnetic charging cable because there are grooves that fit the cable.


The build quality of this power bank is not the best part of it but it does hold well, even though there are two separate pieces for this power bank.


The reliability of this power bank is meant for charging an Apple Watch, using this power bank and expecting it to charge a smartphone to full power even once is not the best reason for this charger.

Specs of the ROMOSS Apple Watch 3,250mAh Portable Charger:

  • Power Capacity: 3,250mAh | Output Capacity: 2,405mAh
  • Output:

Apple Watch Magnetic Charger: 5V/1.0A

Standard Port: 5V/1.0A

  • Input: 5V/2.0A
  • LED Power Indicator: Single LED Power Indicator
  • Size: 4.7 x 1.3 x 1.3 inches
  • Weight: 3.8 Ounces


This ROMOSS Apple Watch portable charger is a different type of charger that does have you take it apart, but it’s all in the name of innovation. What’s not so innovative is the powering that it’s able to provide for smartphones, though.

ROMOSS Apple Watch Charger, 3250mAh Portable Charger for All Apple Watch Series, Dual Port 2A Output for iPhone X/8 Plus/8/7Plus/7/6 Plus/6S and more USB devices-Black (Apple Watch Cable Not Included)

 out of stock
Buy from Amazon
as of July 4, 2020 5:13 am


  • Organize Your Cable and Charge On the Go: Wind your Apple Watch charging cable smoothly around the internal winder of iRoll power bank and then cover case to secure for charging. (Noted: the package does not include the apple watch charging cable)
  • Portable Charger Designed for Apple Watch: ROMOSS iRoll series is especially designed for all Apple Watch products. The 3250mAh capacity battery can charge an Apple Watch 6 times.
  • Dual 2A Output & 2.1A Input: It takes 2 hours to charge your Apple Watch from flat to full and it takes 3 hours to recharge your iRoll power bank. You can also charge your iPhone or other USB device with the spare port at the same time. It can hold one charge for iPhone X.
  • Slim Pocket Size with Great Portability: Easy to fit in your backpack for the trip, lightweight to carry, ideal companion to travel around for your Apple Watch and Smartphone
  • What You Get: A ROMOSS iRoll power bank, a user manual, a micro-USB cable, a pouch bag, a gasket, a user card, 12-month warranty and friendly customer service.

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