Teardrops n Tiny Travel Trailers

Had a trailer made made and threw put the tongue jack to close to the frame
Is 12"x20"x 12"tall ok?

It depends on the size of battery you plan to use. A group 24 size is 7 inches wide, 11 inches long, and 9 inches tall (ish). A 24 inch long box would fit two of these, but a 20 inch long box would not.

I am in the midst of modding a 12x30x12 box to fit 3 batteries. Details here:
http://www.tnttt.com/viewtopic.php?f=50&t=62581&start=315#p1170469

...or just move the jack further forward and build a larger TB so that you can fit the battery and other useful items, both.

If it can be built, it can be rebuilt. Don't let a simple design misjudgment snowball into multiple compromises. Fix it the way you want it to be now. $0.02.

12 x 20 x 12 is fine for a single battery, what Lauren said. No reason it won't work, but as KC said, you could always relocate the jack & have a bigger box.

What's the biggest thing you need in the tongue box & what else goes inside? If there isn't enough room for your plans, move it forward to open up more room, if not, just use what you have. A group 31 battery is about 7" X 9 1/2" X 13" so the box would fit a bigger battery, but not a lot of everything else.

Thanks guys I think I will move it foward

If the crank (handle) on the jack is still in the way due after moving it forward (i.e interferes with the tongue box), consider a side-winding jack. It takes more turns of the handle to move the jack up and down, but a $30-$40 investment in this might save frustration and make your tongue more usable.

I moved the jack foward today
http://oi63.tinypic.com/dher8h.jpg