Anybody tow a trailer with their Clarity PHEV?

[Bryan Keil]

Data point to add. Just completed at 1300-mile road trip in the southeast. Towing a kayak trailer with two boats and a bike and some gear in kayak rear-ends to lighten the tongue. Torq-lift hitch and Curt-butchered wiring, self-installed. Car contained approximately 600 lbs of people and gear. Car tire pressure 38psi. Trailer total wt approximately 370 lbs (50 lbs tongue wt).

No problem with general acceleration or operation. Fuel economy numbers: 27-28 mpg for interstate speeds of 72-75; 32-34 mpg for highway speeds of 60 (with speed-trap reductions as necessary). Sure wish Honda had ditched the hydrogen design commonality and given this vehicle a 10+ gallon tank; range was generally less than 200 miles.

At interstate speeds, the strain on the system was such that HV-Charge tried but could not add to the battery.

 

[Bryan Keil]

Wow, that is some sucky mileage. Just goes to show what drag really does. On my cross country trip we averaged about 50 mpg doing 70 mph. On my 100 drives back from Myrtle Beach to Summerville with speed limits of 45-55, I have recorded mileage of 58 mpg on 2 separate occasions. This is with no energy left in the battery. I did not mention the trip up as the first 50 miles was on battery. Yese the 7 gallon gas tank is a bummer, but at 50 mpg was manageable. What I really don't like is the 1 quart windshield washer capacity. Really saving weight there.

 

[MrFixit]

On my cross country trip we averaged about 50 mpg doing 70 mph

Is your 50 mpg based on what the trip computer is telling you, or did you corroborate this by hand (miles traveled, and gas added). Also, you mentioned no energy left in the battery, but was that true throughout the measurement?

The reason I ask is that people have commented that the trip computer tends to provide an optimistic number (higher than reality). Also, I don't believe it is possible to get 50 mpg at 70 mph unless the measurement includes some net energy from the battery which is not really a fair measure of gas mileage.

 

[Bryan Keil]

Of course this was from the computer, but gas stops we're about what I would have expected. I did save all the gas fill up information, but have not done the math yet. And yes, all figures quoted were with depleted battery. No fair quoting gas mileage statistics while some of the miles were electric. When using partial battery, I never know what my actual mpg is. I would be getting 199.9 mpg all the time while on short trips at home. On this particular vehicle, I have never really checked the accuracy of the computer because it is pretty difficult to do. Except very long trips.

Out of my own curiosity, I just ran the numbers.
Total trip. 3049 miles.
There were approximately 3 full charges, so I will deduct the 150 miles of electric driving.
That leaves 2899 miles driven. I left with a full tank, and upon arrival, I filled up again.
The total was 57.917 gallons of fuel.
That leaves the total as 50.68 mpg. This is approximately what the numbers were from the on board computer.
Driving style was mostly following trucks with adaptive cruise on close follow. Speeds were between 70 mph, mostly 75 mph and several hundred miles at 80 mph. (some trucks drive pretty fast). It was the most comfortable driving I have ever done with adaptive cruise and steering assist. I found that following trucks added about 3 mpg. It was also observed that the more cars on the road, the better the mileage was. Due mostly to the wind tunnel created by vehicle density.
The 58 mpg recorded on my 2 other trips seem reasonable after corroborating the long trip to what the computer tells me. And one more factor is the fact that my tires are down to the last 2/32 of tread left. It has been my experience that worn out tires make for worse gas mileage.
But yes, over 50 mpg is possible traveling at pretty reasonable speeds.

 

[MrFixit]

Driving style was mostly following trucks with adaptive cruise on close follow

Drafting trucks is definitely outside of my comfort zone !!!

But yes, over 50 mpg is possible traveling at pretty reasonable speeds

I can't dispute your data, and agree wth your calculation method. I don't have personal experience at sustaned 70-80 mph, but from what I have heard in this forum, I would have expected mileage in the mid to upper 30's, not 50... I would like to hear from others who have done sustained driving in the 70-80 mph. Have others been able to achieve this?

Out of your ~3000 miles, would you say that you were really 'drafting' or "wind tunneling' for a large portion of those miles?

 

[Steven B]

I definitely think his efficiency is an outlier. I don't even think he's getting more than a 10% benefit from adaptive cruise [so instead 40mpg (what everyone else gets at 75mph), it gets 44mpg] . Even on the shortest distance setting it keeps back four car lengths. I don't know where the other 6 mpg comes from.

 

[NorCalPete]

... I would like to hear from others who have done sustained driving in the 70-80 mph. Have others been able to achieve this?

During my cross-country trip (approximately 6k miles) last June, my mpg ranged from 29.7 (strong headwind) to 48.2 (with 2/3 of battery used), with an overall average of 40.4 mpg. Speeds typically ranged from 70-85 mph. So...nope, no 50 mpg for my car. And no drafting cars or trucks for me either.

 

[Emagin]

If you want to measure real MPG the Fuelly site and eCar app can help
https://www.fuelly.com/
It obviously cannot parse the EV from the HV modes, but it gives you a good sense of overall mileage, as well as long trip mileage when you are not charging.
I've been towing a trailer on top of it and can see mileage drop significantly to 28-30mpg when on trips, closer to 40 on highway and 42 city.

 

[skakub]

Interested in "self-butchered wiring" part do you have any documentation of the installation process? I'm going after a universal wiring kit from ebay (10-20 bucks) and planning on doing it myself. Thanks!

 

[Steven B]

Interested in "self-butchered wiring" part do you have any documentation of the installation process? I'm going after a universal wiring kit from ebay (10-20 bucks) and planning on doing it myself. Thanks!

See post 55 here:
https://www.insideevsforum.com/comm...-anyone-tried-towing-with-their-clarity.5528/

If you find a harness that works cleanly without splicing or splicing less, please post for the community. The one I started with had the matching connector styles and said it was compatible with the hrv so I figured it'd be close.

 

[Steven B]

Post 73 in this thread does a good job describing hitch install:
https://www.insideevsforum.com/community/index.php?threads/clarity-accessories.2331/

 

[skakub]

As a total noob, I successfully wired my Clarity to tow a 4x8-sized trailer. A huge THANK YOU to @Steven B for his patience in sharing his knowledge- it encouraged me to finish the process. Below is the shopping list:

• My trailer - It's well built, it's light for a steel trailer (310 lb), carries 1340 lb (3/4 full of wet hardwood logs), lighting harness is already laid out in the plastic sleeves, so it's a matter of installing it (instructions are useless, follow your gut. It comes with the steel sheet welded onto the chassis (no need for a heavy plywood, like with HF folding trailers), and most importantly- it folds nicely. I keep mine in the garage. I manage to fold and unfold it all by myself (I weight < 150lb). But it is heavy and it's quite a workout. Interesting fact: If you get it online it will come without the signed bill of sale. I had to go to Tractor Supply store in person to get one prepared. I'm new to towing, so it came as a surprise.
• Ball mount for the hitch - mine is 4-3/4" rise. I calculated an optimal rise to be 5 1/4" and this option was the cheapest and closest to what i needed
• Trim removal kit - It's a must. HF kit does
• Current tester - can't get any cheaper than that It did the trick, but I'd get one like this instead.
• Wiring kit - I got it "open box" from Amazon for $45. Note that Steven used a different kit (cheaper), which worked BETTER due to splicing accessories that my kit did not have.
• Micro fuse splice with 10A fuse - i got a 3 pack. Those fuses are total garbage, so buy at least 3 if you plan to pull it out. They just disintegrate, crumble in hands. Splices are ok, one will suffice.

1. The idea is to connect the wiring kit fully inside the car. You will need to conceal the black cable that will run from the converter (the black box of the wiring kit) to the fuse box (not directly to the 12v battery as in the diagram that came with the wiring kit!), (4) cables that will run from the converter to the left light and one last cable that will run from the converter to the right rear light. The converter will be placed in the area under the rear left light, under the liner.
2. Remove a whole bunch of liners and interior panels in the car, to get to the rear left and right lights' cables.
3. Connect the wiring kit to the rear lights: There is no need to remove the rear light, only the plug. I stripped the tape to expose the individual cables that I tapped to, using these, which should be in your kit (see photo below showing one cable, right after i started the process). FOLLOW THE DIAGRAM BELOW (credit to Steven B!). Note two green coming to a single socket. Both are the stop light cables, you can connect to either one. The car light cables are super thin, so you may need to notch the cable sleeves slightly to help expose the copper inside, to make the splicer work. You will end up with quite a bundle! Pay attention to connect ground cables together! (I totally missed connecting those at first)
   
   
4. Continue removing panels all the way to the fuse box. You will conceal the black cable under those panels. I found it way easier doing it this way, rather than elevating the car and crawling under it. Steven B's post shows it very well and the photos will make sense once you remove the panels. Before you start, unplug the negative side of the 12v battery (the right pin). Note, that disconnecting the 12v battery may cause you a headache...
5. Remove the rear seat to access the screw that holds the left vertical panel by the back rest of the rear seat. I had a pdf from some of the car seat cover manufacturer that shows the steps but lost it.. sweep the web and you'll find it. First, remove the screw in the middle of the seat, tucked on the back; see the photos below. Next, unclip (2) clips under the seat. Elevate and hold up by sliding in something rigid, to avoid one dropping back into its socket when unclipping another.
   
6. Keep removing panels until you can run the black cable all the way to the fuse box. Steven B's post shows more photos.
   
7. Splice the black cable with the fuse splice. Install the fuse. Plug to the fuse box. Reconnect the 12v battery.
   
   
8. Once the cables are working (use the tester), reinstall the interior panels, rear car seat, liners.

The only thing i did differently from Steven B was the way i spliced the cables to the rear light, because i used a different kit. Everything else is the same.

I'm a happy camper now!

 

[Steven B]

Persistence pays off. You must have had a second vehicle. I would have given up and taken it to Uhaul.

 

[skakub]

Persistence pays off. You must have had a second vehicle. I would have given up and taken it to Uhaul.

We sold our second car last summer, it was all or nothing thanks again, Steven! We took another trip with the trailer yesterday - everything works like a charm, 40 electric miles, 36mpg after this at speeds up to 65 mph (trailer is rated at 45mph). The cheapest truck bed alternative!