Parasitic Battery Drain

Ok let's gather some data:

What year vehicle?
What level audio?
Any additional systems? Dual battery etc and what brands if fitted...
What accessories or devices are added? Things like USB chargers etc wired in anywhere..

Then.. how old is the main battery?
Do you have std keyless entry or proximity?

Ok.

2008 SE TDV6

Standard Audio.

Standard keyless entry.

Century DIN85LH MF main battery.
Ultimate Extreme 80Ah auxillary battery.
Both 8 months old and hold charge when disconnected.

Trailer brake controller

Traxide SC80 isolator.

Couplertech electronic rust-proofing.

Winch.

What Trailer brake controller?


Also, The couplertec will be part of your problem...
They don't stop rust... but they do help to flatten your battery within a few days. Disconnect it and measure your current draw.

Also, you can test the SC80 draw by disconnecting the green wire and taking another reading.