Labels

USB-C power options for laptops.



Image by: Gan Khoon Lay


When it comes to powering laptops via USB-C without access to AC power there are various ways in which to do so. Prices and functionality can vary greatly. Below, I’ve attempted to cover as much as possible on the topic. The goal is to help inform you of what’s available and help guide your decision on which system to invest in.

TLDR: There are various options for utilizing DC power sources for USB-C power when it comes to laptops. They all have pros/cons. Lists of options for each type offered along with information about each type. This is for anyone looking to invest in or upgrade their current power solution.

Preface:

Lithium-Ion battery capacity is marketed and labeled in two forms Watt-Hours(WH) and milli-amp-hour (mAh) 100WH = ~28000mAh. Generally you can’t fly with anything over 100WH. In some cases up to 2x 101-160WH can be carried onto the plane. No lithium batteries can be checked on any commercial flight.

USB-C offers Power Delivery (PD) which has various protocols from 18-100W (or up to 240W with PD 3.1 ER but that’s not relevant at the moment). PD happen via a negotiation by the two devices (i.e. laptop and charger) based on the capabilities or needs of each device.

Typically, with 2016-2020 15-16in Macbook Pros ~800WH or more is needed for a full day of DC power. This varies greatly depending on your environment and workflow. But 800WH is a good number to aim for when using these models. You should factor in this amount and the charging time of batteries to determine the quantity of batteries you need for your kit depending on which system/direction you intended to use.

The 2021 M1 series Macbook models, can be charged via their proprietary Magsafe 3 to USB-C cable or any of the 3 USB-C ports. The Magsafe 3 cable will work with nearly any PD power source. Additionally, many users have found that the 2021-16in MBP with M1 Max has power consumption that is easily 50% of the previous generation. Needing only 200-400WH total for a day (depending on workload) With these machines, typical still photography workflows only demand 20-40W on average with peaks to 50-60W for brief periods of time. 60W PD input has been found to be enough to sustain a charge.

The options for USB-C power fall into these categories:

  • USB-C power bank
  • D-tap/P-tap to USB-C converter
  • DC to USB-C converter
  • DC to AC Inverters (able to power a monitor)

USB-C power banks

For weight/space you really can't beat USB-C power banks. They tend to offer 60-100W PD (power delivery) And just can’t be matched in their power density, ability to travel and be multi-functional with ability to charge/power other devices.

Popular options include:

There are many other options from various brands but you need to note the charging input as well as output some only charge at 45W which for a 99WH battery will be more than 2hr recharge time. For those that accept 100W input they can be charged in 1-1.5hr. Being that they charge via USB-C you can utilize chargers you might already have and ultimately less cable clutter around as USB-C can be your universal cable.

D-tap/P-tap to USB-C converter

This option relies on robust cinema camera batteries that use Sony’s V-mount and Anton Bauer’s Gold mount. These batteries are available in various sizes, capacities and voltages but the most popular being 14.8V. You can outfit yourself with several 99WH batteries that allow for air travel or a few 250WH if air travel isn’t a concern for you. They can be rented/hired in just about every major/minor city in the world and provides a good back-up option. These battery systems are robust and reliable but come at a high cost. Initial investment for a kit of batteries, chargers, mounts and power converters can easily exceed $1,000. Another factor for these batteries is size and weight. In general, they are larger, bulky and their chargers are quite large and cumbersome. There have been more compact options for the batteries in the past few years but the chargers still tend to be rather large. Additionally, they tend to charge rather slow when compared to other options. Good chargers have higher amperage allowing for faster charge but some batteries will still require 4hr for a charge. For faster charging you want a charger with a higher amperage per channel. I believe 6A tends to be the common rate on the higher end. Anton Bauer, CORE SWX, IDX are just a few of the quality battery makers. You will see many lower cost options but do your research prior to buying as with batteries in this area you get what you pay for. You’re paying for reliability, quality cells, load balance and thermal overload protection.

Popular options include:

Each of the options linked above has its own pros and cons. This option is a great choice for you if you’re already invested in the battery system. Additionally, the batteries can be used to power many lighting options as well as inverters to power other AC power devices.

DC to USB-C converter

These options allow for powering via generic DC sources, power banks/batteries and vehicles that output 12-36VDC. Some of these were the first options once USB-PD came around. They offer a very low cost of investment but come with some quirks and each type of battery might have it’s own dedicated charger. Many of the batteries offer high capacities that are too large for air travel. These options are great for the “DIY” type and allow for customization. Some are geared toward 12V car charging but can easily be adapted to use with the battery of your choice.

Popular options include:

Countless other options are out there when you look for 100W PD DC options. You can build a custom system to meet your own needs but it might not be the best for travel work.

DC to AC Inverters (options to power a monitor)

This option is ubiquitous and comes in many sizes/shapes and price points. This option is also the least desirable in many cases as it’s the least efficient. You are converting DC to AC and back to DC for laptops. Each conversion comes with a 10-20% loss of energy due to inefficiencies in the system. That loss comes in the form of heat. Some of these systems offer DC output and or USB-C PD output anywhere from 18-100W-PD. Many of these systems also have integrated batteries that can’t be replaced by the user. This means you might need multiple units or a VERY large unit that wouldn’t be conducive to a mobile workflow due to its size/weight. These units vary greatly in their features and capacity. Some offer quick charging, some can work with V-mount or Gold Mount batteries, some use their own proprietary replaceable batteries. The major positive aspect many of these units offer is that they can power other devices outside of laptops and monitors and can save your butt sometimes. Being the monitors of choice for the still photo industry don’t offer DC input this is often the only solution for powering monitors in the field as gas generator aren’t always welcome.

Popular options include:


Image by Joel Wiseneski

USB-C Cable Choice:

When purchasing USB-C cables that you intend to use for charging/power you should ensure they are rated for 20V/5A or 100W. (There’s a new USB-C PD 3.1 EPR coming that will allow for greater power but that’s not a concern at this time.) When you purchase cables, know that many rated for 100W only offer USB 2.0 data rates. This shouldn’t be an issue in most cases. There’s a cool USB-C cable that offers an LCD display to show you the real time current. More about that cable here: Add One Of These To Your Kit! 

Cables Matters and Anker are great choices for quality cables.


If you would like to support the efforts of the blog you can donate here or here.

Labels: