12V USB Socket Stops Charging

[Howler]

Hi, There are several BlueSea Systems model #1016 12V USB outlets on our boat. They worked fine for two seasons. This year, for some strange reason, when you plug in an iPhone or other chargeable device, it only charges for a short time, then stops well shy of fully charged. The green lights on the sockets remain on when this happens, so the sockets are apparently getting current. Any ideas what's wrong, or suggestions on how to troubleshoot?

Other facts that may be relevant:
- The battery bank is only a couple of years old and works well
- A few weeks ago the green light went out on the USB socket for a night, then came back on (electricity ghosts?)
- I've tried with multiple charging cables and devices

Here's the product page from the manufacturer: https://www.bluesea.com/products/1016/

Thanks!

[sailormed]

I don’t it is user repairable. There is an ASIC I guess that transforms the 12V to 5V in the plug. It regulates the device to be charged and sends a signal over the 2 wires not used for charging to the device being charged. There must be something strange going on with the communications between the device and that ASIC.
I would not know how to trouble shoot this with the traditional cruisers toolbox.