Looking for some advise on charging an auxiliary battery.  The battery is in the tack/dressing room, 12v deep cycle, to run both exterior working lights and the interior lights as needed.  It is enclosed in a battery box with removable lid. 

Can I charge this battery on the same 12v. wire that charges the trailer breakaway battery?   Or, would that be too much load on the vehicle charging system?  Is it possible that it would draw my truck battery down if I didn't unplug the trailer wiring when at a show and vehicle isn't being run all day?

 Can I wire up a float charger to recharge the battery after a weekend of using the lights (is a float charger enough to recharge)? 

I am trying to set up something that is easy to use and doesn't require that I open and close the box all of the time.  Any suggestions would be appreciated.

Thank you

Yes it's possible. One thing to consider is the wire size will have to be fairly large due to the length of run to eliminate voltage drop in order to charge the battery. Unless your truck auto disconnects the Aux charge circuit on your trailer plug, you do run the risk of draining the truck battery if you don't unplug the trailer when parked.

Yes, find one that performs multiple charge states or you risk boiling the battery dry over long term. I use one of these during winter storage. http://www.amazon.com/Battery-Tender-021-0127-Junior-Charger/dp/B00...