Monday, January 30, 2023


RV Daily Tips Newsletter Issue 872

Issue 872 • March 27, 2018
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RVing Tip of the Day

Beef up your towable/camper charge wiring
By Russ and Tiña De Maris
“Can I use the 7-way wire connector from my truck to my camper or trailer to charge my RV battery?” It’s not an uncommon question, and the answer is, “Yes, you can.” But the answer is also, “You can, but you probably don’t want to.” Much depends on your power needs and your aptitude as a do-it-yourselfer.
A “7-way connector” is the plug that brings electricity back from your pickup to the RV’s running lights, the back-up lights, and the stop, turn and taillights. There’s also a connection for ground and one for “battery.” This last connection is there to allow the truck’s charging system to route voltage back to the RV’s “house” battery – the one used to power interior lights and run the water pump and other low-voltage equipment.
Can you use it? Yes, you can. The circuit will (if properly wired and equipped) bring voltage back from the truck charging system and charge up the RV battery. But because of the long “run” of wire from the engine compartment of the truck back to the location of the RV’s own battery, it can be a very poor way to charge the battery, taking far too long to be of any real value. We can illustrate it this way: Suppose you want to fill your fresh water tank. Would you rather use a garden hose to fill it up or a hose the size of a drinking straw? If you had plenty of time you could eventually fill the tank with the straw, but the narrow diameter of the straw would severely limit just how fast the water would flow.
The same is true with electricity. The typically equipped wiring from the alternator back to the 7-way connector on the truck bumper is skinny, skinny, skinny. The same is usually true for the wiring running back to the camper or trailer battery from the RV’s own connector. You need a “bigger hose.” Here’s what some RV owners have done to make battery charging with the truck alternator practical.

First, use a battery isolator. This device only allows voltage to flow from the truck charging system back to the rig when the engine is running. This prevents the RV from sucking down the truck battery, leaving you in the woods with no way to start up. From the RV side of the isolator, install a 12-volt circuit breaker to protect the circuit. This breaker should be based on the output current of your truck alternator.
Next, it’s never a good idea to mix battery chemistries in the tow vehicle and trailer. For example, if your truck has an AGM (Absorbent Glass Mat)) battery, then this will only work if your trailer also has an AGM battery. If your truck has a standard flooded cell lead-acid battery, then your trailer needs the same type of battery for this charging system to work. And certainly any trailer with a lithium-ion battery would need to have the same type of battery chemistry in the tow vehicle if you plan to charge this way. Paralleling different battery technologies without special charging circuitry can result in under- or over-charged batteries. 
Run a large-gauge (8-gauge or larger) single wire back from the circuit breaker down the truck frame to the bumper. Secure it well with wire ties, and keep it away from moving parts and exhaust system components. At the bumper end attach a heavy lock-twist electrical receptacle, rated at 30 amps or larger, to the “hot” lead. At the same time, connect another wire to one of the other terminals in the connector, and connect the free end of the wire to a portion of the truck making a good electrical ground.
A corresponding electrical plug is used to connect the camper side up. Use this same-size wire, only you’ll need two conductors, and run them as directly as you can back to the camper’s house battery. Mind your polarity, keeping positive to positive, negative to negative.
It’s good to find a “cover” of sorts to slide over the prongs of the RV plug, as it will always be “hot.” Covering the prongs will keep them from shorting against anything. Your imagination will help you figure out the plug cover, based on the size of the plug. 

Test your new installation with a digital test meter. With the truck engine off and the plug connected, test the voltage of the house battery. Now fire up the truck engine, and within a minute or so, the voltage at the house battery should show a higher reading.

Did you miss the latest RV Travel Newsletter? If so, read it here.

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Plug your 50-amp coach into a 30-amp plug
There comes a time in every RVer’s life when there will be no 50-amp hookup available, only a 30-amp plug. That’s when this adapter will save the day. If you don’t have one, get one. Or you’ll be sorry. Learn more or order


Have a short sewer hose handy
Use a very short (3′) sewer hose when dumping tanks at dump station. Park close, then you  don’t have to drag out (and clean) the long one.

Keep specialized spare parts in your RV, always!
With electricity expert, Mike Sokol
I’m a road dog and typically drive 50,000 miles a year teaching production seminars around the country. Many times I’m thousands of miles from home and driving solo. One thing I’ve learned the hard way is to keep a variety of specialized spare parts in my road kit. For instance, I keep a serpentine belt, belt idlers, diesel fuel filter, fuses, headlight bulbs, brake light bulbs, and metric torx wrenches along with anything else that might be hard to find on the road. I also keep a notebook containing printouts of any special repair procedures for my vehicle. This has saved my bacon many times. I can often find a decent truck shop on the highway, but they may not have a particular part for my Sprinter. I just show them the printout of the repair procedure, give them the new spare parts from my kit and let them get to work. I don’t have time to wait for an order or even have someone drive to the next town for a parts pickup, so the more spares I carry with me the better.

Easy clothes line
Dog owners, need a quickie clothes line? Stretch out Rover’s retractable cable and you’re all set.

Laundry wars: The case of the angry camper.

Lawn chairQuick Shade Chair keeps the sun off you!
Summer is ahead and that means a lot of time outdoors. But, oh, that also means lots of sunshine and for many of us that’s not a good thing for our skin. Here’s a great way to be outside and keep those nasty skin-damaging days away – this highly rated Quick Shade Canopy Folding Camp Chair. Learn more or order.


JudgeHighway laws in all 50 states
Everything you need to know about driving in all 50 states. See the minimum and maximum highway speeds, how much you’ll pay if you get the maximum penalty for reckless driving, and more! [Editor: Apparently this information regards cars, rather than RVs. But it’s still interesting.]

Big Rig Resorts
Own a big rig and seem to have trouble finding parks, or places to park it? This website is dedicated to finding spots to park that big boy. 

RV Factory Tours
Ever wonder how your RV was made? Find your factory on the map, visit and tour it! Learn the whole RV-building process. 

Check out the long list of great RVing-related websites from

coleman propane stoveColeman Classic Propane Stove
Sometimes, you just want to cook outdoors. Maybe guests stopped by. Maybe you and the next door neighbors are gathered outside and it’s a whole lot more fun to cook up your bacon and eggs or boil your veggies without heading back alone inside your rig. This Coleman stove is just what you need. Learn more or order


VW Beetle tows fifth wheel travel trailer
Talk about a lightweight setup! This VW bug-fifth-wheel combo was likely somebody’s grand idea, but it never made the big time, much less the production line. But it sure is fun to watch it in operation in this now-classic video.

See all of our videos on our YouTube Channel.

Join us in Elkhart May 17-21
RV Travel will be a major participant at the upcoming RVillage Rally in Elkhart, Indiana, May 17-21. Join editor Chuck Woodbury, our Pet Vet Dr. Deanna, RV electricity expert Mike Sokol, tire expert Roger Marble and our RV historian Al Hesselbart — all of us presenting seminars and hanging out with RV Travel readers. Included in the rally will be several factory tours and a visit to the fabulous RV Hall of Fame museum (with many classic RVs). Learn more, and get a special discount code to save 10 percent on registration.


fire extinguisherFire extinguisher reminder
Check your RV fire extinguisher(s) regularly – at least once a month. Take it off the rack and check the pressure dial to make sure it’s in the “good” range. Turn “powder” or “dry chemical” extinguishers upside down and thump them on the bottom to loosen up the chemical – if it settles and hardens in the bottom, your extinguisher is useless.

Don’t forget about the birds and the bees
Bugs, birds and bees: Cute in the wild, but lousy when they wind up in your exterior refrigerator or water heater compartments. Add “inspection and clean out” to your regular maintenance list.
Do you have a tip? Send it to diane (at) .

‘Earthquake Putty’ keeps stuff in place
Do you have items in your RV you like to keep in place — on a table, bedstand or counter? You need this. Quakehold Museum Putty is designed to keep items secure in earthquakes! Hey, a moving RV is a constant earthquake! To use this, pull off what you need, roll until soft, apply to the base of the object then lightly press it to the surface. Later, it comes off clean. RVers love it! Cheap, too! Learn more or order.

Join us: On RVillageFacebookTwitterYouTube.

Billy was in a store with his mother when the clerk gave him a free stick of candy. Billy’s mother asked the boy, “What do you say to the man?” “Charge it,” Billy replied.

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RV Daily Tips Staff

Editor and Publisher: Chuck Woodbury. Managing editor: Diane McGovern. Staff writer: Emily Woodbury. Contributing writers: Russ De Maris, Bob Difley, Gary Bunzer, Roger Marble, Deanna Tolliver, Mike Sokol, J.M. Montigel and Andrew Robinson. Advertising coordinator: Gail Meyring.

ADVERTISE on and/or in this newsletter. Contact Gail Meyring at Gail(at) .

Everything in this newsletter is true to the best of our knowledge. But we occasionally get something wrong. We’re just human! So don’t go spending $10,000 on something we said was good simply because we said so, or fixing something according to what we suggested (check with your own technician first). Maybe we made a mistake. Tips and/or comments in this newsletter are those of the authors and may not reflect the views of or this newsletter.

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James loyd
4 years ago

I have enjoyed the articles in the news letters and learned much from them however I pull a 30 ft trailer and wonder if ther is a place to go to find helpful information about traveling with them. Thank you

4 years ago

Your article talking about the ‘7 way connector’ left out that one of the spades is for the brakes. Hope no one inadvertently hooks up to the brake spade for some other use and ends up with no brakes.

Another Mike
4 years ago
Reply to  Mike

Also, the battery power wire is there to keep some charge in the house battery so if the trailer disconnected the break-away switch would have power to lock the trailer brakes.

Ralph Caldwell
4 years ago

The website of the day today “50 States of Speeding: Laws for every state in the U.S.” does not include the trailer towing speed.
“The maximum speed limit on most California highways is 65 mph. You may drive 70 mph where posted. Unless otherwise posted, the maximum speed limit is 55 mph on a two-lane undivided highway and for vehicles towing trailers.” This error makes the other information on the “50 States” website unreliable.

4 years ago
Reply to  Ralph Caldwell

CA, OR, WA all have lower speeds when towing a tow car or trailer/5th wheel. The website link ONLY works for automobiles, not RVs.