# Power I/O on the AC12

The [Verkada access controller](https://docs.verkada.com/docs/access-control-datasheet.pdf) physically connects to door components to manage access. Access controllers work with your building’s existing door hardware and readers.

## Powering methods

There are a few different ways to power the Verkada [AC12 one-door controller](https://docs.verkada.com/docs/ac12-one-door-controller-datasheet.pdf). Some features are limited, depending on the selected mode:

* Powering the device with a PoE++/802.bt connection (60W)
* Powering the device with a PoE+/802.at connection (30W)
* Powering the device with a PoE+/802.af connection (15W)
* Powering the device with a DC12V connection (30W)

The AC12 is unique from our other access devices:

* You can power it exclusively by Power over Ethernet (PoE) with the same duty limits offered by other Verkada-wall-powered solutions.
* (Optional) You can power it with a DC12V in connection.

{% hint style="warning" %}
Depending on the primary power and enabled features, [different current and voltage limits apply to the lock](https://docs.verkada.com/docs/ac12-one-door-controller-datasheet.pdf) as shown below:
{% endhint %}

## Restrictions with accessory devices

By default, the second reader power rail is disabled.

{% hint style="danger" %}
To enable this power rail, configure the access controller as an input/output (I/O) door. Required to enable this reader.
{% endhint %}

By default, the USB output is disabled.

{% hint style="danger" %}
For access and use of the USB power, you must enable from the settings page of the AC12 in Verkada Command.
{% endhint %}

By default, PoE output is a 30W PoE+ connection. This can have limitations if all accessories are enabled and powered down to a 27W max output. For more information, see [PoE Passthrough on the AC12](/access-control/installation/access-control-deployment-best-practices/poe-passthrough-on-the-ac12.md).

## Use the DC12V input

You can use the DC12V input to:

* Power the unit as a primary supply in 30W mode.
* Use in conjunction with PoE power to serve as a backup power supply.

The AC12 requires a battery charging device to be used with a battery backup. Connecting just a 12V battery to the 12V input does not keep the battery charged over its operation.

{% hint style="danger" %}
⚠️ Do not connect a battery to the 12V output to charge it. This may damage the battery.
{% endhint %}

## UPS backup on the AC12

To facilitate a UPS backup on the AC12, we recommend these options:

* Connect to a switch on a UPS.
* Utilize a 12V output from a battery backed up external power supply.
* Utilize a 12V DC connection from a wall outlet independent of the main switch.
* Provide PoE power from a battery-backed-up external power supply.


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