Note for
@mully95 &
@Kevin frazier (& anyone others who have DEcosse KeyLess system) please note that there IS a standing drain with that system - there has to be so the RFID module can 'poll' for the presence of the remote. But it should not kill the battery in couple of weeks (my relatively small LiFe battery in my Daytona needs to be recharged every couple of weeks if not ridden, but the capacity of an RIII Lead-acid battery will exceed this many times over). If you ride fairly often (at least once per week) then there should not be any need to have a trickle charge to maintain it, although it is good insurance to do so.
For
@Chullera - I
don't believe you have my keyless (didn't mention any accessories other than your USB and you would certainly detect a draw if it
were installed)
If you truly cannot measure any drain current with key-off, then the battery must be self-discharging. It seems odd that you have experienced this with multiple batteries, however it seems to be the case, at least on the data supplied. There is nothing OEM that draws any current with key-off other than a tiny, tiny amount to maintain the Trip Memory in the instruments.
I would however have expected the USB to draw
something even with no device connected (although the difference with say a phone for example would be quite dramatic, as much as several amps)
Check the condition of your battery to begin with - charge your battery, then complete a substantial ride, whereby you believe the battery to reasonably well-charged.
After return, turn on the Ignition (and thereby also the headlight) - what is the voltage you read across the battery in this condition? And just as importantly, how quickly is it dropping over the course of say 1 minute? That will give you a good indication of the general state of charge of your battery. With a single headlight, this should certainly be at least in the low 12's and maintaining with only a quite slow rate of voltage drop. (for twin H4 headlight models, at least high 11's is probably still acceptable)
If below this threshold and dropping at a fair clip, then your battery fundamentally has a problem.