Use the Hardwiring Cable or Ultra Battery (B-130X).

BlackVue dashcams can activate Parking Mode when stationary for five minutes (G-sensor/accelerometer-based activation). 
Since the X Series, BlackVue added built-in voltage monitoring to most of its models (except for the DR750X-2CH LTE Plus Series). 
Those models can be hardwired directly to the fuse panel to instantly activate Parking Mode when the vehicle's ignition is switched off.
With an hardwired Ultra Battery, it is also possible to connect the dashcam to the Ultra Battery so as to support ignition-based Parking Mode as well. 

Go for Power Magic Battery Pack (B-112) or Ultra Battery (B-130X).

If you are looking for a simple plug-and-play installation, both batteries offer the option to plug into the cigarette lighter power socket.

Note that Power Magic Ultra Battery supports easy cigarette lighter installation. However, we recommend to hardwire it for faster charge (unless you have more than an hour daily commute, in which case you will fully charge the battery anyway).

Choose Power Magic Ultra Battery (B-130X) or Battery Pack (B-112)

If your vehicle sports a small-capacity battery or an aging battery that you do not feel like replacing just yet, an external battery is the way to go. Whether you plug it in the cigarette lighter socket (B-112/B-130X) or hardwire it (B-130X), a Parking Mode battery will only draw power when ignition is on. Since your vehicle battery would not give you a lot of Parking Mode time anyway, it may be a better choice overall.
If you use the cigarette lighter configuration for your battery, make sure that your vehicle's cigarette lighter socket is not powered when ignition is off, so as to preserve your vehicle's battery.

Pick Hardwiring Cable, Power Magic Pro, Ultra Battery, Battery Pack (in that order)

The Harwiring Cable is a simple 3-wire (Battery, Accessory, Ground) harness so it is definitely the easiest to hide for a clean-looking installation. 

Power Magic Pro is a small accessory that allows for a stealthy installation in the majority of cases, although it will vary with each car configuration. PMP is easy to hide as you can usually put it in the fuse box. If you want to maintain access to it (to reach the Parking Mode switch), you can install somewhere out of sight under the steering wheel.

The Power Magic Ultra Battery, in spite of its larger size, can be stealthily installed as well, as it is able to connect to the fuse box (recommended installation) and tucked under the driver's or passenger's seat or glove box.

The Power Magic Battery Pack is harder to hide since it requires to be connected to a cigarette lighter socket.
Also, if you want to use the USB ports of the B-112, you will likely have to keep it somewhere in sight. However, if your car features some inconspicuous cigarette lighter power socket, the B-112 can be both handy and stealthy.

1 hour for Power Magic Battery Pack, 50 or 90 minutes for Ultra Battery.

The Power Magic Battery Pack (B-112) plugs into the vehicle's cigarette lighter socket exclusively. It takes about one hour to reach full charge and can power most BlackVue dashcams for 8 hours (dual-channel) to 12 hours (single-channel).

The Power Magic Ultra Battery (B-130X) can either be plugged into the cigarette lighter socket (5A charging) or hardwired via the fuse box (9A fast charging):

• With 5A power, it takes about 90 minutes to reach full charge.
• With 9A power, it takes about 50 minutes to reach full charge.

It can power most BlackVue dashcams for 19 to more than 30 hours, depending on your dashcam model.

Power Magic Ultra Battery 

Power Magic Ultra Battery gives you the most power (96Wh) without affecting your vehicle's battery. 

If you have a very large car battery, the Hardwiring Cable or  the PMP can also work. That said, you need to factor in the long term wear of your vehicle's battery as well in case you use Parking Mode often.

Please avoid combining Power Magic accessories. Read below for more details.

One of the most common questions we get is "Can I connect a Power Magic Ultra Battery (B-130X) or Battery Pack (B-112) to a Power Magic Pro (PMP)?"

The reasoning is usually that the PMP would feed power to the dashcam via the B-112 or B-130X, then when the vehicle's battery reaches the voltage cutoff value, the PMP would stop drawing power from the car's battery, letting the B-112/B-130X take over. That way, you would get longer Parking Mode time by combining power from both the car's battery and the B-112/B-130X.
Although this could seem like a good idea, it does not work.
Here is why:

1. The Power Magic Pro is rated for a 1A output (Max 2A) as it is designed to power your dashcam (less than 0.4A draw). Meanwhile, both the Ultra Battery (in cigarette lighter mode) and Battery Pack draw more than the Power Magic Pro's max rated current (5A and 3.5A respectively). That means either Power Magic battery would blow the Power Magic Pro's fuse while charging or would take forever to charge.
2. Even if the PMP could sustain the amperage required by the B-112 or B-130X, it would likely not give you a lot more Parking Mode time in most cases. First, if the B-112 or B-130X was not fully charged while turning ignition off, it would draw about 10 times more power than your dashcam does, meaning it would drain the car's battery about 10 times faster.
3. Drawing that much power from your car's battery while ignition is off will wear your battery much faster, so it is definitely not recommended.