Drilling into the A frame

Btw, a couple small holes in the top flanges of the trailer tongue frame pales by comparison to the load applied by a steel truck box and hundred of lbs of batteries.

Holy carp, that thing is all batteries!
Generator or a decent charging circuit from your alternator would be a more effective and less costly solution imo.
You running NASA ops out of your OFF ROAD POP UP?

Like stated, prolly won't hurt to pop a couple small holes in it. You'd be drilling in the top flange which is typically in compression except when the trailer bucks over a bump, but that stress is going to be less than the constant tension stress on the bottom flange from the trailer loading. Plus the flanges are doing more for lateral stability and direct tension on the frame than holding up the weight of the trailer. The web provides most of the vertical strength.
Top flange, best place to reduce the section (drilling a hole), neutral axis of the web next, bottom flange next, top of web next, bottom of web worst spot. In general of course, without having calced the stresses and designed the beam.

I added two right angle metal strips to the top of my A-Frame between the Propane Tanks and the Trailer wall.

This is what my three batteries looks like sitting inside the angle strips... I bolted the battery cases to my angle strips in lieu of the strap you mentioned


When I added four batteries to my battery bank I replaced those angles with longer units so I could mount my four battery cases which the two outside batteries extend out some over both sides. I could have just added longer strips on top of the ones I added but decided to go ahead and replace them.

This also allowed me to drill most of my holes into the added angle strip with only one bolt into the top of the A-FRAME.

I thought about welding these on but of course the large amount of heat might do more structure damage then drilling...

I'm glad I didn't weld anything as things keep changing. I am now wanting to install one of those 48-inch Truck Side mount boxes to install four Trojan T105 6V batteries in to go across my A-FRAME so I add some security from thief for my batteries...



Roy Ken

Welding the A frame is much worse for it than drilling a couple of holes. I have drilled mine both on the top and the sides.

Once to reposition my tanks and then to mount Gas Can Holders to the Sides.

Drilling 1/4 inch holes should not be a problem at all structurally. It's best if you can drill in towards the center of the web or middle of the side of the square tubing, as the stresses in the frame member under load tend to be lowest there.

You should not have the batteries and their wiring exposed. I think that may be forbidden by DOT standards, actually; but even if it is not, having protection from the elements and from getting shorted out by debris or dropped tools is a very excellent idea.

Some sort of a shackle or U-bolt arrangement might also work well to secure things to the frame.

do not know about drilling, but i wanted to add two batteries and welded two carriers onto the side of A frame. if you put them were you want are you sure they will not be to tall. i was going to try that, but they would have hit the trailer

I don't think a couple of 1/4" holes will be a problem. However if it starts to look like termites took over . . .

Are there any holes left over from the manufacture? If they are in the wrong location, perhaps a hook can be bolted to your platform, and hold it in place.

My other thought is clamping from top of the frame to bottom of the frame, so you might have a 7/8" thick unistrut under the battery platform, and clamp to that? That would avoid any holes into the frame.

If it is tempered steel, it will be difficult to drill through it. Use plenty of oil, and start out with a smaller pilot hole, say 1/8"?

You will find that the pair of 6 volt batteries will last much longer than the 12 volt they replaced.

Good luck!

Fred.