We put in a brand new deep cycle battery April 14, everything worked fine. Today I could only get it 1/4 way up. Since it was STILL plugged in to the tow vehicle I started the vehicle, after a few minutes the trailer went up the rest of the way. Would leaving the plug for the lights and brakes plugged in to the tow vehicle (for a week) and the master switch in the raise/lower position drain the battery?
We have had the trailer for 4 years this is the first time DH just parked it and did not unplug from the tow vehicle! Or could it just be a bad battery.

It's "semi-rare" for a new battery to be bad, but it happens. However, I suspect there is something inside the trailer that is imposing a constant draw on the battery when the trailer is not in use.

In my case, it was a radio/CD/DVD/TV player that had a "keep alive" circuit that was ALWAYS on, even when the Master Switch was in the middle, traveling position. I inserted a simple on/off switch in the device's power circuit and my dead battery problems went away.

You need to check for this kind of "vampire draw" and to do it you need a multimeter with an Ammeter function. You have to connect the Ammeter to a battery cable in series with the battery and then, if you see ANY Amperage reading, you have this problem and you have to find out what is causing it. From your description, the battery was not completely discharged, just low, and that means the drain on it was small.

I don't see how leaving the trailer plugged in to the TV would cause a dead battery and I doubt leaving the MS in the raise/lower position would do it either.

But, I just remembered that the TV plug on my trailer developed an internal short last year and I had to replace it. Yours COULD have a very small current leakage that shouldn't be there that would drain the battery over time. My suggestion to check the battery with an Ammeter would find this with and without the trailer connected to the TV.

Good luck - these kinds of problems can test your patience!

- Jack

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Leaving the fridge turned on in 12-volt position can drain the battery even with the master switch turned off. It is wired straight to the battery.

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VERY true, but I think the battery would be at absolute zero if you had done that. The fridge puts a heavy draw on the battery and will drain it in a matter of hours. However, Rich is giving everyone a serious warning here - make sure the fridge is NOT running if you don't need it on.

From your description, you have a small "parasitic" draw on the battery. Something much like the one I had from my media player.

- Jack

What about the break away switch on the tongue? Is it pushed in all the way or is it just bad? Just something else to check.

Bob

That's certainly something else to check if you have battery failures, but again, I don't think that's the OP's problem, because the break away switch puts full electrical power to the brakes and I'm certain the battery would be completely dead if it were tripped.

I suppose though, it's possible for a tiny short to exist in that system, that would provide a small constant current to the brakes and would drain the battery like he describes.

For such a simple electrical system, there are a surprising number of things that can (and do) go wrong!

- Jack

We took the battery back to have them test it. Bad Battery! They couldn't even get it to charge

That(semi-rare) made me LOL!!!!!!! I had my share..Suspect connections first the Battery...Thats my Moto

It's kind of a "Murphy's Law" sort of thing, isn't it? Personally, I don't think batteries are made as well as they were in the good old days.

I'm pleased you found your problem, gypsy, in spite of my attempts to steer you wrong! Good on you!

- Jack

LOL, Jack. I kept telling my DH, but I didn't do anything different then the last 4 years!

Glad you found the problem was the battery Gypsy.

Here's a tip for finding problems on the road. You do not need a multimeter to find there is a drain although that is the right instrument to determine the cause. You can simply disconnect a battery terminal, best to use the negative (ground) side, but either will do. Connect a test light or a simple 12v light bulb between the battery post and the terminal wire you removed. If the light glows, you have a current draw.

You can find a light bulb in your interior lights or your tail light. Set the base of the bulb on the battery terminal and touch the battery cable to the side of the bulb. If it lights, you've a current draw.

You can use a lower voltage bulb if necessary but it may burn out if the current draw is high. This may not work with LED type bulbs as they require a minimum level of current to "light" and they may work in only one direction - reverse the LED leads in that case.

In Gypsy's case, if she had placed a bulb between her negative battery post and the negative wire the bulb would not light up and she'd suspect her problem was the battery. Or the multimeter would have indicated no current draw.