Word of warning

[barryd]

Maybe (in my simple view) the only way to know is to plug the 4 way back in and try and recreate the problem. When the voltage drops can you then unplug the 4 way and see if it immediately goes back up again or / and check it with a multimeter across the actual terminals? My bet is its a false reading and the batteries hadnt really dropped that far. Its really odd. Something funny going on though.

 

[colinm]

I got a couple of cheap 12v to USB adaptors (not the ones as OP), one overheated and failed, but it was noticeably hot, took the other apart and it was very poorly built, I now only use quality 12v to USB adaptors.
Couple of thoughts as to why you didn't notice it being hot, did you feel the entire part, i.e. plug, socket, wire and the tv plug (which might have made poor contact in extension but good when used without it) also it might have been multiple poor quality connections which 'spread' the heat loss across the whole item.

 

[Fisherman]

I got a couple of cheap 12v to USB adaptors (not the ones as OP), one overheated and failed, but it was noticeably hot, took the other apart and it was very poorly built, I now only use quality 12v to USB adaptors.
Couple of thoughts as to why you didn't notice it being hot, did you feel the entire part, i.e. plug, socket, wire and the tv plug (which might have made poor contact in extension but good when used without it) also it might have been multiple poor quality connections which 'spread' the heat loss across the whole item.

No Colin I only tried the unit. But I did not see any issues with the plug. Also the plug is fused surely the fuse would have blown. This is a bit of a mystery. I will go back out to the van one evening and watch the tv for two to three hours, just to make sure it’s ok, cheers.

 

[Nabsim]

Tv should only be using around 2 - 2.5ah though so that shouldn’t really be noticeable for a couple of hours