Powerpoles For A TH-D75 Charging Cradle KSC-25LS

I have a KSC-25LS charging cradle for my Kenwood TH-D75 handheld. This charging cradle comes with an AC/DC power supply which provides 12V to the cradle. I wanted the option to power the charging cradle directly from any 12V DC power source connected via Powerpoles.

Because the charging cradle accepts 12V DC, I expected that I wouldn't need to do any sort of voltage adjustment; the nominal 13.8V should work fine. After completing the project and testing, I can confirm that a 13.8V source charged a battery in the cradle with no problems.

I elected to add Powerpole connectors in the middle of the existing charging cable. This approach required no additional parts other than the Powerpoles, and lets me choose whether to power the cradle with an external 12V source or the included power supply. If you don't want to splice up your current cable, you can buy a pigtail with the correct DC jack and make a new cable. You need a male 5.0mm x 1.1mm DC plug to fit the KSC-25LS.

When making DC power cables, it's important to get the polarity correct. Most DC power cables provide current on the center pin and the ground on the barrel. You can verify this by looking for a small graphic near the DC input on the device. As you can see here, the positive icon goes to the center pin, so this plug matches the typical pattern. This is also easy to verify using a multimeter.

With a little bit of trepidation, I cut the wire between the power supply brick and the DC output pin. I added shrink tubing to each piece, crimped on the Powerpole connectors, then used a heat gun to shrink the tubing for a finished look. I tested the output after the splice, expecting positive current on the center pin, and got the same 12.35V as I did before the splice.

Confident that I had a working cable, I connected a 13.8V power source to the charging cradle via the new Powerpole connection. The battery charged just fine. I measured a steady 750 milliamp current draw during the entire charge cycle.

With this relatively easy modification, I now have more flexibility in powering the charging cradle. With 3 amps at nominal 12V, I can charge one battery in the cradle, and charge another battery attached to the radio, while simultaneously operating the radio. I'm looking forward to taking advantage of this capability on extended trips in the backcountry where there is no utility power.