Battery dead on 07 trail lite

[Jono1234]

A new issue arose on my recently purchased RV, when my battery went dead. I thought maybe I left something on but when I put an ohm meter from trailer frame ground to positive terminal I found no resistance (direct short) by a process of elimination of removing fuses I determined the short is coming from the component side of the fuse which powers all the lights in the cabin and the propane detector and God knows what else. I really don't know where to begin nor do I understand why the fuse doesn't blow. I know when I leave it on A/C power all appears normal. Guess I need wiring schematics and a better knowledge of inverter technology. One last thing it , when a/c connected the battery is receiving 13.3 volts so I believe the investor is ok. I know this isn't good with car mechanics and maybe it isn't blowing the fuse because it's a leak and not a direct short although it ohms out at less than one ohm. My big concern right now is safety no breakers are popping nor any blown fuses ever but showing any kind short from power to ground concerns me greatly when A/C current is involved. Any assistance is appreciated

[atreis]

It's very normal for the positive to be wired directly to the frame and is not a sign of anything being wrong. (This ends up coming in handy should you install an electric tongue jack, by the way - only one wire is needed.)

There are devices that run all the time and will drain your battery if you don't disconnect the battery - e.g. propane leak detector, and the like. Most people that don't leave their trailer plugged in and don't have solar panels end up installing a battery disconnect switch in order to keep the battery from going dead.

[THenne1713]

THE RESISTANCE OF A LIGHT BULB is very low, TWO bulbs = 1/2 resistance of 1; FOUR bulbs= 1/4th; put a bunch in parallel and it can very well look like no resistance; TRUNK LIGHTS can easily be left ON by mistake and NOT seen during daylight hours. (TIP: CONVERT TO LED BULBS); Check age of battery, water levels, corrosion, etc. NE cell low means a BAD cell. Get battery charged/ tested if not too old, otherwise replace. A battery switch can help greatly to reduce battery discharge from Propane Leak Detector, etc. while in storage unplugged

[McKannick]

In every RV there are many little culprits that suck on the battery even when unoccupied and everything turned off that has a switch. If the battery is already more than 50% discharged several times, it's in a weakened state and will go flat even more quickly. If your rig doesn't have a battery isolation switch, either get one installed or disconnect the ground cable so that it won't go flat again.
Should you find the battery is bad / old / under rated for your RV, be sure you get a deep cycle marine style replacement battery, NOT a car or truck battery. A car battery is made to give a huge jolt of amperage to crank an engine, NOT to slowly be supplying current over an extended period as an RV battery needs to do. Probably should be some info on your rigs electrical system that would help guide you on the replacement battery amp-hour requirements. If can't find anything, perhaps a 'rule of thumb' (guess) would be to add up all the fuses in your system panel and multiply by 2 and add 10% for the amp-hour rating of the battery.