I may be wrong, but I think TMCC and DCS need certain triggers from AC to make some things work.
In my Williams E7 I have the BlueRail board and a 2" GEMS bluetooth speaker installed for onboard sound (sound is in the BlueRail but comes out of the Ipad). With the bluetooth speaker I just make sure my Ipad "sees" it and the sound then comes out of the engine. Could probably put a smaller speaker in for use in a smaller engine.
Less than 1/2 of my engines are equipped with LiPo batteries, so far no trouble charging them in the engine/tender.
I've got a couple of 1/16 tanks with LiPo batteries in them. The chargers are CHEAP (made) compared to the one I have for my trains and have had no issues with them either. Charging at 1amp/hr vice fast charging is the answer. All my others have NiMh batteries. All my engines have modern can motors, brushed.
I get 2-1/2 hours of run time, course I don't run them flat out either. I either use the 4-wire connector that came with the Williams engines or the 10-wire straight connectors that MTH sells for my steam engines. On diesels I just run the wires from the motor and lights to the board I'm using.
There's a few videos around of some of my engines and those of Bob Walker.
