Back in 2017 I had to shop around a while to find this adaptor which seems less likely to interfere with radios than say the Sporty's adaptor. It seems this adaptor is also available at Aircraft Spruce now, but I liked this smaller shop. I just ordered two for the club Debonair which I fly as it has no USB power out installed.
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Dual USB Dual Voltage (12-24VDC) ULTRA FAST Charger (4.8A) | PilotLights.net
Product DescriptionThe Quicki Dual Voltage / Dual USB charger is a compact and powerful device for ULTRA FAST charging your portable electronics. Built for rugged use in any 12 or 24 Volt vehicle, it provides 2.4 Amps of charging power to both USB ports (4.8A Max, 60W).A combination of internal...