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· Registered
34 Posts
Discussion Starter · #1 ·
Hey guys,

Yesterday I put 125 miles on my 2018 Clarity PHEV split across two separate trips (morning and evening). About 65 of those miles I was traveling between 65 and 75 mph. Maybe 20 of those miles were stop-and-go city traffic (traffic lights, congestion, etc.) The remainder was medium-speed highway, between 40 and 60 mph. The temperature was around 29 Fahrenheit. I did not use cruise control. The entire trip has a lot of curves and rolling hills.

I left the house with an estimated 48 miles of EV range (full battery from my Level 2 charger) and 165 miles estimated HV range. I pre-heated the cabin on house power using the app before I started my trip in the morning. I then drove about 25 miles on EV at highway speeds, until my estimated EV range was about 20 miles. Then I pressed the HV button, and continued my trip the remaining ~40 miles keeping the battery at about 50% charge. For a lot of this 40 miles of HV, I was traveling at 75 mph, or 80 mph downhill. My morning trip of 62 miles took about an hour and 15 minutes, to give you an idea of average speed.

To my surprise, going 40 miles on HV in the morning consumed about 80 miles of HV range. So I went from 165 miles of HV range down to 85. Now, my trip home was only 62 miles, so with 20 miles of EV range and 85 miles of HV range on the way home, in theory I would have enough gas+electric to get home with plenty of range to spare.

But about 15 miles into my trip home, after driving through city traffic, my HV range was down to 50. It was looking like my HV range was off by at least a factor of 2 -- the Clarity was being too optimistic -- so I was at risk of running out of gasoline and/or battery entirely if I kept going. I panicked and stopped into the last gas station before entering a long highway and filled up the tank.

Once I filled up my tank, I drove about 20 miles on EV and depleted the battery. The EV estimate was very precise; it said I had 20 miles left and I got exactly 20 miles out of it. I then had 20 miles of highway driving left and had to use HV. For these last 20 miles, my HV range estimate went down by 30 by the time I got home. The estimate was getting better -- only 1.5x too optimistic instead of 2x. My trip home took an hour and 35 minutes, so there was a bit more stop-and-go traffic and lower speeds.

Maybe the driving conditions were egregiously bad? But it looked like the EV range estimate was excellent, it was just the HV that was unrealistically optimistic.

Anyway, this is just my own experience. I don't think I have that range estimate bug that everyone mentions, because on a full tank my estimated HV range was 343 miles. The EPA estimate is 340 miles total with a full battery and a full gas tank, so that's a little high, but it is definitely in line with my relatively gentle driving style. I do travel at high speeds on open freeways, but I don't accelerate aggressively, pass people, or drive with the windows down. I wasn't carrying a heavy load, either.

Does anyone have a similar experience with the HV range estimate being high compared to actual range? This was kinda scary, because if I hadn't made the decision to stop and get gas before entering the freeway, I could possibly have gotten stranded with no battery or fuel and had to call for someone to bring me a gas can. That freeway didn't have many exits.

The moral of the story is, take the HV range estimate with a grain of salt, and if you're in doubt, go fill up your tank. For whatever reason my EV range estimate is always extremely accurate.

· Registered
2018 PHEV Touring Atlanta, GA
1,090 Posts
Good detailed information. The actual moral of the story though is to only rely on the fuel gauge, which is the bars on the right hand side. Those are not an estimate they show what is actually in the tank. I have never heard of the fuel gauge being inaccurate. Now it's not necessarily linear so like with any car it takes some experience to learn what 1/2 tank means, 1/4 etc, and even empty, which like with any car doesn't mean really empty there is still some gas left but of course you don't want to rely on that.

That being said I do use the HV estimate, but only around town, where the worst case scenario of a bad estimate is that I might have to get gas somewhere other than my normal gas stations. But on a trip I wouldn't just take HV range with a grain of salt, I would completely ignore it and only look at the fuel gauge.
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