Pullin the PIN for the brakes would be a big NO-NO for me. Each BRAKE MAGNET will pull around 3AMPS each with the 12VDC applied from your trailer battery.
There is also a big change you will destroy your electric brake magnets - they are not free... The electric brakes are not designed for continuous use like that.
I would definitely do a complete electric brake inspection since you have done that all night long.
Another issue is with the battery being run down below the 50% charge state. This starts a internal process inside you battery and will eventually need to be replaced. You should never let your deep cycle batteries get below 12.0VDC and not be re-charged right away. The first signs is poor performance of not holding the charge like they used to and the worse case thing is they will short out between the cell cores which requires replacement. batteries are not cheap either... I lost one of my four original batteries in 2009 by not having the smart mode charger and it boiled out its fluids and shorted out its cells inside. I then replaced the converter/charger unit for a PD9260C and my remaining three batteries have been doing great since then. They are just now starting to fall back abit on performance after 6 years of use. We do alot of camping off the power grid and do the usually charge cycle of 50% to 90% for 12 or times each morning during each camping trip.
Got to do what you need to do to respect the batteries... They are your lifeline when camping off the power grid. I watch my homemade DC MONITOR PANEL like a hawk when camping off the power grid. When they hit the 12.0VDC point I will shut down using them. This took some planning in the beginning on how we use our batteries and it always occurs now at around 8AM the next morning when it is time to re-charge the batteries when allowed by the generator run time restriction in place where we are camping at.
My next step is to install some solar panels to keep me from having to run the generator so long each morning. Once I get past the high DC current demand when first starting charging then the solar panels can do their job the rest of the HIGH SUN day. I will still have to run the generator for about one hour if I had a couple of solar panels installed. Room on my OFF-ROAD POPUP camper roof for solar is going to somewhat of a challenge due to weight of the added panels.
I'm rambling on here haha...
Roy and Carolyn
I claim Horse Creek Country in Southern Ill - Momabear is from North Texas
We live in King George VA
RETIRED DOD DOAF DON CONTRACTOR Electronics Tech 42YRS
"We're burning daylight" - John Wayne
2008 STARCRAFT 14RT OFF-ROAD POPUP with PD9260C and three 85AH 12VDC batteries
2010 F150 FX4 5.4 GAS with 3.73 gears - Super Cab - Towing Package - 2KW Honda EU2000i Gen
K9PHT (since 1957) 146.52Mhz
"We always have a PLAN B"