question about battery

troubledwaters wrote:

camperdave wrote:
Even with the disconnect switch on the off position, you will still have a small load...

That is not always true. When I turn my disconnect switch off, everything is off; there are zero loads connected.

Even the emergency battery powered brake system? That is the most important thing to have powered and should always be powered even with a disconnect switch interrupting any power to the trailer. It will draw no current when in the standard, non operating, position so isn't a drain on the battery(s). If the emergency brake switch on the trailer tongue is not powered, add a wire, a fuse, and the correct terminals from the switch to the battery, bypassing the disconnect switch.

The reason this is best practice is that it makes the emergency brake system operable, even with operator error of forgetting the switch before traveling.