Moshi IonSlim 10K full review

After releasing one of the sleekest, most attractive 5,000mAh power banks around in the IonSlim 5K, Moshi is back to do the same again for the 10,000mAh range – this time with added support for USB-C PD.

If that string of jargon means nothing to you, here’s what it boils down to: this is a slick portable charger that can keep your laptop topped up just as easily as your phone – in theory at least. But is that enough to trouble our best power bank chart?

In terms of design, this is basically a slightly chunkier update of the 5K version. The curved body has a smooth anodised aluminium finish, with a simple, understated Moshi logo in the centre of the body. It weighs just 236g, and at 1.3cm/0.5in thick it's impressively thin for its capacity. This is the rare power bank that you can comfortably carry in a pocket, let alone a handbag, and we still love that about it.

There's a simple button to show how much power is left, with four LEDs that light up to indicate how much charge is remaining. Then there are the two ports: USB-A and USB-C, used for both charging other devices and recharging the IonSlim itself. 

The former is a pretty standard 12W USB-A port, which is enough for respectable fast charging, but the second is more interesting. The USB-C port supports Power Delivery, supplying up to 30W. That means it's enough to top up a laptop or Nintendo Switch, which drain power too quickly for the average power bank to keep up. Check out our other recommended Switch power banks if you're interested in gaming on the go.

Don't get excited too quickly though. For one thing, at 30W the IonSlim 10K is right at the lower end of laptop chargers in terms of power delivery. Taking Apple's lineup for example, it's similar to the 29W charger supplied with recent MacBooks, but will charge much more slowly than the 61W and 87W chargers that are standard for the MacBook Pros. That means that depending on what you're doing and what laptop you're using, it might not quite keep up with your usage, but will at least do much better than a non-PD charger.

The bigger issue is the capacity. At a stated capacity of 10,000mAh you should probably expect something around 6,600mAh of actual usable power (every power bank loses some to heat and power inefficiencies). That's enough to charge a typical phone a couple of times over, but might not even manage a single full charge of a laptop depending on the capacity.

If all this sounds pretty negative so far, let's be fair: Moshi doesn't really claim that the IonSlim 10K is suitable for completely charging a laptop, and instead suggests that it can provide "emergency power", which is really the right way to look at this. It's not going to replace your wall charger, but if you're on the go and just need to eke out another 10 percent to finish up a project, this is light and small enough to be perfect for the task.

It's also handy for charging your phone at the same time. Moshi supplies two cables with the power bank (USB-A to USB-C, and USB-C to USB-C), and this is cable of charging two devices simultaneously through both ports, with an output of up to 35W when it's charging two devices at once - slightly more than the 30W that the USB-C port on its own caps out at.

The big downside to the IonSlim is the price. This is a beautiful little power bank, and it's likely to make its way straight into my Switch carry case for charging on the go, but at almost £100 (with no official US price yet), this is a lot to pay for it, and at the time of writing it's only available through Moshi's own store.

You can buy an Anker equivalent with more than double the capacity and USB-C PD support for about two-thirds the price - it won't look as nice, but it'll get the job done better.

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