Update: Though custom cables are still available from Jim, KD2ZVM, inexpensive versions are now available from Amazon for the various voltages. JacobParts makes 12v and 15v ones and sells them in packages of 2 for about $13. The Farsense USB-C to DC adapter cable allows you to choose your voltage by pushing a button.
In the previous blog entry I described the use of USB-C as a power source for a rig such as the KX3. My friend Jim now sells a very compact version of the needed USB-C Power Delivery (PD) power dongle and cable on his website.
The USB-C PD (power delivery) system allows for a variety of voltages (9, 12, 15, 20v) to be called up by an external “decoy” board. For simplicity and compactness, Jim’s cable has a small 15v board built in with a series diode to drop the voltage to 14.7v, just under the 15v maximum for the KX3.
In my previous entry I was using a rather large power bank as power source. However, this dongle makes possible all sorts of compact and sophisticated packs for portable use. Many of these packs, often advertised as charging power banks or packs, have built-in monitoring of battery condition and even voltage and current output. Moreover, they usually include a variety of ports and can also be used for charging phones and other devices.
For example, this $60 one from Amazon claims a capacity of 30000mah and provides monitoring of battery condition and current draw. With a USB-C PD wall charger (not included), it claims a recharge time of only 3.5 hours. The listing does illustrate one caution in choosing a power pack: it claims 65W output, but that’s split between several ports. One test found that it put out 43W, just what is needed to power a KX3 at 15W. This has not been tested with a KX3 at this point but I hope to post some tests results here later.
There are many other options, some of them quite sophisticated and multipurpose. Omnicharge is a reputable company (omnicharge.com) and offers the Omni Mobile 12800 as well as the higher-capacity Omni Mobile 25600. Renogy.com is another reliable company. And there are many other options on sites such as Amazon. Just make sure it has a USB-C PD port with, for the KX3 at 15W, 40+W capacity.
The world of batteries is changing quickly and packs like these suggest lots of possibilities.