The Nintendo Switch‘s battery should last long enough for most people, but road warriors may discover it has an annoying charging quirk that will require them to buy a new portable battery solution.

Nintendo’s new hybrid home/handheld console is due out this Friday (read our review), and it has a USB-C port on the bottom. You can use that to connect it to its dock and play games on your TV. But you can also use it to charge directly from the wall or from a battery pack using a USB-C cable.

Only you may run into problems if you try to play your Switch while charging it with a portable battery pack. That’s because Nintendo’s console absorbs a relatively high voltage, so your battery may continue to drain even while plugged into a lot of battery packs that are currently made for smartphones. I have a 10,000 mAh portable battery pack that charges my phone and tablet without breaking a sweat, but its two 5-volt USB outlets can’t provide the Switch with enough juice to stop the battery from draining during use.

In my experience, the Switch still lost about 1 percent-to-2 percent of battery every 10 minutes when the system is playing a game and connected to my portable charger. That means that if you notice your battery is low and want to continue your Zelda adventures while plugged into most power banks, you’re battery is still going to drain and eventually die.

The reason for this issue is that the Switch comes with a 15-volt power cable, and it likely requires something in that ballpark to give its processor the energy it needs to run. You see similar issues with laptops. Even a Razer Blade, which charges from USB-C, won’t charge from most portable battery packs because of voltage discrepancy.

If you want to charge the Switch while playing, you’ll probably need something more robust — like this $136 Maxoak USB-C power bank that supports up to 16.8 volts. That’ll get the job done, but it’s also bulky and nearly half the price of a Switch.

Now, that’s not to say the Switch won’t charge at all from a standard mobile power bank. In sleep mode, my battery recovered nearly 3 percent battery when plugged into the battery for 10 minutes. This means that if you want to use your Switch on the go a lot, you’ll want to plug it into the portable battery whenever you put it in your bag. Otherwise, you may find that you can’t charge and play when you really want to.