Hello,
The battery of our ZTT260 is slowly emptying its power. I read here that the sat nav and TV could cause a battery drain, but as I've fitted a modern Chinese radio, I took out those modules of the boot.
I disconnected the battery and pulled out the fuses one by one. By measuring between the plus of the battery and the battery clamp, I couldn't find any fuses (neither under the glove box, nor in the engine bay) or any relay, which would decrease the high amperage.
I read in the forum too, that an older battery could also cause discharging, so instead of buying a new Varta every 4 years, I added a 2nd battery in the boot. Hope this will solve the problem?