Power cord access while TM is closed

Larry:
It's almost scary how many of us here on this site think alike...

But I guess that's why we own TrailManors...

Gregg

[Bill]

If any of you are concerned about your lead-acid battery's vented hydrogen gas collecting in a confined space, then replace your conventional battery with an absorbed glass mat battery when you need a new battery - or batteries. The AGM batteries, such as the Concorde ones, come equipped with special caps that convert the hydrogen and oxygen back to water.

Larry - yours is the best of all possible solutions. But for those of us (like me) who are waiting for the OEM battery to die before replacing it, the special caps are also available for regular batteries, too. I use them. Zap! No possibility of free hydrogen! Love it!

But really, the fact of the matter is that hydrogen (or propane, or acetylene, or any other flammable gas) is not explosive until it reaches a rather high percentage of the local atmosphere. A whiff will not do it. I'm not sure of the specific value, but any of these gasses have to build up to maybe 25% of the local atmosphere before it becomes explosive. So if a battery generates, say, 1/2 cubic inch of hydrogen, and that half cubic inch of hydrogen is trapped inside the tiny head space of a battery, then yes, it can be explosive. Hence the labels on the battery (though I've never actually heard of a battery exploding - it is like the McDonald's warnings: This hot coffee is HOT - don't spill it on your lap. But if that same 1/2 cubic inch of hydrogen is released into the thousands of cubic inches of space in a TM, well, it is just totally inert. Light all the matches you want, spark all the sparks, nothing happens. Your furnace connection leaks more propane into the interior than this. In my opinion, if the battery is being charged anywhere near properly, there will be an insignificant amount of hydrogen produced, and the special caps will reduce that to zero.

Bill, wouldn't it be possible with your circuit to run the power line into a 115 volt ***outlet**** mounted inside a weather tight aluminum enclosure located on the outside of the TM? Then, when you want to provide 115 volt AC power to a closed TM, you would connect the TM to a live 115 volt AC outlet with a cord containing a male plug at each end.

Yes, this is another good idea. However, you should run 115 volts to an ***INLET*** on the TM, not an ***outlet***. In other words, mount a male connector (plug) in the weatherproof box, and then use a standard extension cord to make the connection from the house to the junction box on the TM. You wouldn't want to use a double-ended male cord because if you plug one end of such a cord into a power source, the projecting pins on the other end are immediately LIVE! Try brushing that against your thigh or a metal surface as you set things up! EXCITING doesn't begin to cover it!

One of our members has done exactly what you describe, in fact - a very nice installation - and may post pixs of his work. But I will leave that to him.

Bill

We had a battery explode in our Dodge Ram Charger. Had just returned from a long trip, unloaded vehicle, my husband went for a pizza while I unpacked. When he went to restart the Dodge, it exploded. Did a lot of damage. Those caps sound nifty.

Betty Ann

I implemented a simplified version of the 'run forever' power cord mod on my 2720SL about a month ago. It works great.

First, thanks to 'Bill' for his excellent design and documentation which made the project possible.

I have posted some pictures on my personal webpage at http://mywebpages.comcast.net/wbarber20/tm.mod. The pictures are my first attempt at using a new digital camera, so beware. Also, they are not of mush use without the following explanation.

I figured we only needed the 12v power part of Bill's design, so I eliminated the 120v power to the refridgerator. What we wanted was a way to keep the frig running after returning from a trip without raising the TM.

Eliminating the 120v circuitry let me cut back from a DPDT relay to a SPDT relay and greatly simplified the running of the wiring.

Here is what I did - FIRST DISCONNECTING THE BATTERY so there was no live current, 120v or 12v in the trailer.

1. Removed the necessary screws and pulled the entire power panel/converter from the wall location under the bathtub (see photo inlet.1). This gave me access to the trailer fuse panel wiring.

2. Mounted the relay on the flat surface on the back of the panel and mounted the fuse holder through one of the spare wire holes toward the left end of the A/C fuse panel (see photo inlet.2 and look closely at the left side to see the rear of the fuse holder.). The fuse location allows me to change the fuse, if necessary, just by opening the fuse panel door and unfastening the two hex head screws which hold the 120v fuse panel cover in place.

3. Outside the trailer (on the driver's side) I removed the black plastic cover which protects the bathroom plumbing. I had bought an inexpensive 10ft 16 guage grounded extension cord and cut off both plug ends. I pushed the wire up past the plumbing and toward the rear toward the vent underneath the trailer near the power panel. A lot of the trailer wiring routes through this shared space with the bathroon plumbing. The wire went right through  nearly to the panel. It was easy to grab it and connect it through the fuse to the relay.

4. The wire from the converter is nicely labelled by TM and it made connecting it through to the relay easy - if you haves Bill's schematic.

5. Underneath the trailer again, I drilled and filed a hole in the frame for the male power plug inlet. I routed the wire along the top of the frame and then through the opening in frame for the torsion bars and from there into the inlet hole (see photo plug.1 and look for the black extension wire.

6. Next, I mounted a weatherproof outdoor plug cover over the power inlet (see photo plug.2 with the cover held open).

7. Last, I sealed all the wire and mechanical connections with GE RTV108 silicone rubber adhevsive. RTV108 is waterproof, it insulates and it glues every thing in place. The idea was to provide a waterproof and vibration proof installation.

TESTING:
I used my ohmeter to check all the wiring, then plugged power into the inlet to check the relay operation and turned on an interior light to check 12v power (the battery was still disconnected). I tested the 120v receptacle and the shore power plug to make sure that there was no 120v connection in the trailer. I then unplugged the inlet and plugged in the regular shore power to make sure 120v and 12v power worked as they did before the 'run forever' addition. With that complete I put the plumbing cover and the power panel back in place, re-connected the battery and started using it.

We have taken two trips since the installl, one of them over really bad back roads and everything has stayed in place and works fine.

Here is a short parts list :

SPDT relay Magnacraft 781XAML-120A (~$8 from Allied electronics).

120v male power inlet from Allied (~$1.75)

Fuse holder and 10 amp fuses from Radio Shack.

16 guage extension cord (~$3) and black weatherproof outdoor plug cover (~$4.75) from Lowe's.

NOTE: The TM is open between the powerpanel, the bottom vent and the external bathroom plumbing. I don't think there is a heat problem. In fact, I now use the 'run forever' connection to keep the battery charged when the trailer is not is use.


LAST NOTE: Wade started this thread last year when he had a 2720SL.  I bought it from him last fall, so now that 2720SL has the 'run forever' mod - small world, huh??

Originally Posted by Bill

Back on August 12, Wade started an interesting thread titled 2720 Wish List for his then-new TM. The third item on his wish list - a wish shared by many - was to Engineer access to the power cable for battery charging and refer while closed. The group kicked around a number of thoughts, looking for a method that was both convenient and SAFE. Consensus was that a small auxiliary cord would be OK - no need to use the big 30 amp cable, which isn't normally accessible when the TM is closed. In this discussion, I was the safety guy - I couldn't figure out a way to have two power cords without creating an electrical hazard. (I am an EE and sometimes electrician.) The thread eventually petered out for lack of a solution.

I have thought about the question off and on since then, and the solution - a convenient and SAFE solution - finally popped into my head. And it is easy, and parts cost only about $10-15.

The desire is to put the plug end of a small AC power cord in some spot that is accessible when the TM is closed. My choice would be the back bumper compartment. If this cord is plugged into a source of AC power, then it will provide AC power to the refer and to the battery charger, and nowhere else. If the cord is unplugged, then the refer and charger AUTOMATICALLY revert to the big 30amp power cord. The word AUTOMATIC is important - with AC power projects, nothing should depend on the memory of a weary traveller. And furthermore, if BOTH the big cord and the little cord are plugged in, there must be no hazard.

The solution? In my 2720, anyway, one of the 20 amp circuit breakers in the AC power distribution panel feeds both the refer and the power converter. At the output of this breaker, we insert a changeover relay. The relay is wired up so that this circuit is normally fed from the big 30amp cord, but if the small cord is plugged in, the relay activates and feeds this circuit (and this circuit only) from the small cord. Voila - the function is accomplished.

If anyone is interested in doing this, I will provide a diagram and source for the relay by email. (The board's server doesn't seem to be accepting graphics during the site change.) WARNING: I do not encourage you to undertake any AC power project yourself if you are not throughly comfortable with AC power wiring, house wiring, etc. The job is not hard, but as you know, the consequences of doing it wrong can be severe.

Bill

Bill , could you send me your diagram for power cord access while the TM is closed ? Thanks . David Dennis [email protected]

[Bill]

David -

This is an oldie, but I found the info. Go to Doug's TM Photos web site (tmphotos.org), click on Photos here, and open the album that has my name on it. The info is on the second page.

Bill

Bobby (aka wmtire) and I have been PMn a little trying to come up with a power cord solution for the older TMs like ours, and I have this idea.....just haven't got the parts together for the modification.

I want to drill a small hole in the back compartment down to the bumper storage area.....big enough to allow a 30 amp extension cord and maybe cushion with some wiring harness conduit to go through it. Buy a 30 amp extension cord.....about $36 for 30' at Wal-Mart. Cut the female end off of the cord, leaving a couple of feet of the cord and male end. Feed the cord up through the hole, and reattach another female end to the cord. When I need power to my TM while closed (but before closing), I would pull the current plug and cord back through the side of the TM, and feed it through the access hole in the back, and plug into the short extension cord that I now have running from the rear compartment to the bumper storage. Pull the bumper plate, and plug in. At developed campsites, I would rerun the original cord back through the side of the TM, and use as intended....or just hook it up in back again. I would also add a male end back to the extension cord that I cut, and still have ~25' extension cord.

I am wanting to do this modification to have the ability to leave the fridge (on 12v) and fan running during the nite before leaving on an early morning trip, and not have to lower the shells in the dark the next morning.

I think there was a suggetion out there sometime in the near past, that a large power cord grommet would allow you to pull the entire plug through this area, but I want to keep the hole small.

Whatcha y'all think.....would that work OK??

Chap

[Bill]

Chap -

That will work fine. Just as a note, the only time you need a 30-amp power is when you want to run the airco. You could make a smaller hole, and maybe avoid any cord-cutting, if you used a 15-amp or 20-amp extension cord that has regular household plug and socket ends. Then use a 30-to-20 amp adapter to mate with the TM cord. This will provide more than plenty of capacity for the use you describe.

Bill

Originally Posted by Bill

Chap -

That will work fine. Just as a note, the only time you need a 30-amp power is when you want to run the airco. You could make a smaller hole, and maybe avoid any cord-cutting, if you used a 15-amp or 20-amp extension cord that has regular household plug and socket ends. Then use a 30-to-20 amp adapter to mate with the TM cord. This will provide more than plenty of capacity for the use you describe.

Bill

Good thinking.....I definitely won't be using the AC while the unit is closed, so I might just go with your idea on that.

Thanks, Chap

I suppose this "mod" is for older TMs. The 30 amp cord on my 2006 2720SL is just as accessible with the TM closed as it is with it open, though you do have to be careful when opening or closing the TM to not let it (or its cover) get snagged by the support arms.