Equine RVer
We are in the market for a motorhome. We plan to tow a three-horse trailer. The trailer, when loaded, will weigh a maximum of 10,000 pounds. We assume we’ll need a diesel pusher. We’ve sought advice about this, but everyone seems to have different ideas about the horsepower, torque, chassis, and hitch that we’ll need. People also have talked about the load capabilities from axle to axle, but we’re unclear about that, too. Can you help?
Tom and Patti Maechler
Via Email
You correctly assumed that you will need a diesel for the weight you’ve mentioned. Before you think about horsepower and torque, check the coach’s specifications for its gross combination weight rating (GCWR). That is the maximum weight of the towing vehicle and the loaded trailer, including cargo and passengers. You estimate that the loaded trailer will weigh a maximum of 10,000 pounds (five tons); therefore, the GCWR must exceed the gross vehicle weight rating (GVWR) — which is the maximum allowable weight of the fully loaded coach — by more than five tons.
A coach that meets the GCWR requirement should also have the needed horsepower and torque, plus a chassis strong enough to safely support a Class IV hitch. A Class IV hitch is the minimum needed for the estimated towing weight. It is rated for 10,000 pounds and up to 1,200 pounds of tongue weight if an equalizing hitch (also known as a weight-distributing hitch) is used. For that much weight, an equalizing hitch is definitely needed. With the proper application, it will minimize bouncing and side-to-side swaying.
Finally, it’s a good idea to check with both the chassis manufacturer and the coach manufacturer of any vehicle on your short list to verify that it will fit your needs.
Shaky Starter
I have a 40-foot 2005 Monaco Dynasty with 16,000 miles on it. It has a Cummins ISL 400-horsepower engine. My problem is intermittent. The starter sometimes engages on the first turn of the key, but other times it may take as many as 10 tries to engage. Each time, I hear a click sound from the engine compartment area. Ambient and engine temperatures and the length of time between starts don’t seem to matter. Before replacing a solenoid or starter, I would like to be sure these symptoms aren’t caused by another component in the starting circuit.
Jim Denton, F395407
Carnation, Washington
First, clean all the battery cables, and the next time you experience a failure, check the starter solenoid. Have someone attempt to start the engine while you use a digital voltmeter to check the output lug of the starter solenoid to make sure it is getting full voltage/the same voltage as the input lug. You could also check the voltage at the starter while someone attempts to start the coach (with safety stands in place). Even a loose wire on one of the high-amp connections can cause intermittent issues.
The motorhome may have a dirty or corroded starter. Since you mentioned throwing parts at the problem, I’m assuming you feel comfortable doing your own work. If that is the case, you could disassemble the starter, clean it thoroughly, and reassemble it. Or, if there is a shop in your area that can competently rebuild electrical engine assemblies, have them go through it and clean it, and replace any component they deem necessary.
Inverter Issues
I own a 2016 27-foot B+ NeXus RV motorhome with about 36,000 miles on it. I’m on the third Xantrex inverter, an 1,800-watt Freedom HF. The inverter experiences intermittent problems while I’m driving. It stops working and a “High Voltage” message appears. Once it’s reset, the problem stops. This has happened about 12 times in the last six months, and only while driving the coach — sometimes more than once a day, or not for a week or two, or not at all. Perhaps even more oddly, I have not had any inverter problems whatsoever while parked at a campground and connected to shore power, which we’ve done numerous times.
Another issue occurred recently when I was dry camped in a parking lot with the refrigerator connected to propane; that time, the inverter stopped working and a “Low Voltage” message appeared. A mobile tech checked it out and was puzzled, because the batteries were testing right around 12.6 volts. The coach has four 6-volt batteries, and they seem to hold their charge well.
I have had the coach looked at by NeXus and Xantrex. Their techs — and anyone else I’ve asked — just scratch their heads and say it might be the wiring, but they have no idea why, where, or how. In fact, I bought the coach new and before I took delivery, NeXus already had switched out the inverter for a second one.
Do you know why these issues occur?
Bob McMinn, F411351
Massapequa, New York
Brett Wolfe, resident moderator on FMCA’s online Forums (community.fmca.com), and “RV Doctor” Gary Bunzer respond:
Brett: Check the alternator output, both for correct 12 volts DC (not more than 14.4 volts DC at either the chassis battery or the house battery), and to verify that no AC current is exiting the alternator.
The low-voltage warning can occur — even with the battery at 12.6 volts DC — when a heavy load is placed on the inverter, particularly if the cable that runs from the house bank to the inverter is long and/or of insufficient gauge wire. Loose or corroded connections on the cables from the battery to the inverter can be another cause of excessive voltage drop at the inverter. It would be interesting to put a digital voltmeter on the battery lugs of the inverter and see what the actual voltage is when the low-voltage alarm sounds.
Gary: I’m inclined to agree with Brett. I’d verify the sizing of all the cables between the alternator, engine ground, inverter inputs, ground cables, battery separation device, etc. — everything on both the positive and negative sides of the DC system from stem to stern, and all connections in between. I’d bet there’s a substantial voltage difference measured at the battery posts when compared to the inverter input connections. Also, as Brett mentions, the AC load being served may be taxing the inverter — either its output rating or connections, etc. A temperature measurement also would help. We’ll all be guessing, however, since hard measurements need to be documented.
Cost Of Heating
I would like information that compares the costs of operating various heat sources in a motorhome. Efficiency should be factored in. For example, the cost of propane per gallon versus the cost of heat pumps and electric per kilowatt.
Paul Legare, F286201
Fryeburg, Maine
One of our technical writers suggested this as a general rule of thumb: Multiply your electric cost per kilowatt by 20 and compare that with the cost of one gallon of propane. The lesser number is the cheaper option.