After being coded, what is the real range at 75 or 80 mph?

[jadnashuanh]

At say 70mph, if you don't have your dynamic cruise control set to maximum following distance, IMHO, you are being unsafe. I still contend, a 2-second gap is wise, and at that distance at speed, you won't be drafting. Depending on conditions, the ACC doesn't always recognize a vehicle ahead, and you may not have time to recover. I use it all of the time, but I'm not close enough to anyone to actually benefit from their draft. Even the Tesla, with more cameras and radar can make mistakes...the much simpler camera on the i3 is good for what it does, but nowhere near the point where I'd want to be close to the vehicle ahead at speed.

There is an advantage to following a big truck...they tend to look ahead, anticipate, and are smoother in their driving, unlike some people that can't seem to maintain a smooth pace and are always darting in/out of traffic to get ahead of just one more car.

 

[bwilson4web]

. . .
There is an advantage to following a big truck...they tend to look ahead, anticipate, and are smoother in their driving, unlike some people that can't seem to maintain a smooth pace and are always darting in/out of traffic to get ahead of just one more car.

I would add that those who would tailgate a single, small car on a four lane road will see the truck and pass both the car and truck. In effect, the truck is camouflage and a place to hide from those who would follow us too close.

In the following images, I'm using dynamic cruise control set to the minimum following distance:

The lead pickup truck is along side the truck and the following truck has already past me.

Here we see two cars that would easily fit in the space between the me and the pacing truck. The second car is easily tailgating the front car.

Bob Wilson

 

[jadnashuanh]

Looks like maybe 100' or so to the truck. At 70mph, that's about 1-second of travel time. The recommended safety margin is 2-seconds. Yes, people drive that close, and no, they really shouldn't at speed. That's why they came up with the 2-second thing...people couldn't remember x car lengths at one speed, y at another, and so-on. It's easy to estimate 2-seconds by just counting when the vehicle ahead passes some reference, and then how long it takes you to cross it.

Back to the OP's question...when your battery charge is getting quite low, the car will start to limit how fast and how much you can discharge the battery. The higher your speed, the steeper the grade, the more load you have in the car, the more things you have on, you're falling back on the REx to try to maintain the SOC...it's not going to be able to. It certainly can if you reduce the load (speed is probably the biggest, easiest thing to do that). If you don't, the SOC will continue to decrease, and may leave you sitting by the side of the road while the REx builds some charge back up, assuming you have any fuel left. Obviously, every road is not uphill, and the load changes considerably when you go back down, but speed is a big power hog. At some point for that day, your tire pressure, the temperature, your speed, you will max out the REx's capacity, and will be also drawing down the internal battery. With the original REx, that's around 70mph on flat ground. It appears you may get a little more with the newest versions, but not a huge amount. Just the difference in drag between 70-75 is an increase in drag of about 15%. That makes a significant impact on your overall maximum range. 70-80 is almost an increase of 31%.

If you can live with those restrictions, you can keep driving the i3 as long as you keep filling the gas tank about every hour or so, depending on conditions and when you're assured of finding an open station. If on an interstate, depending on where you are, you may need to stop at shorter intervals to ensure you can find an open station. Depending on where you live and drive, if you're lucky, you'll find an operational, open CCS unit. But, instead of 3-4 minutes to get out and fill the tank, you're talking about more like a half-hour or more, depending on your charge level. Find only an EVSE, you're talking about 3-4 hours, or maybe more, depending on the size of your battery, its SOC, and the capacity of the EVSE.

This is why I don't consider an i3 all that convenient for a road trip. It's great around town, and the REx can certainly help if you decide to take a detour, but it would not be my first choice on a long trip. Doable, yes, desirable, no.

 

[jsinclair]

We just recently took a 780 mile road trip with our 14 rex. At 30°f and 70-73mph with no wind we were loosing about 2% soc every 10 miles. At 50°f and 77-80mph we were still loosing about 2% soc every ten miles. We did fast charge along the way , but if we wanted to drive slower we could have done it all on gasoline.

 

[viking79]

The i3 is a city car, tall stubby and blunt, not designed as a highway cruiser; get yourself a Bolt, or wait a few years for a Tesla 3.

Really? You suggest one of the other stubby and blunt city cars not designed as a highway cruiser? The Bolt EV is almost exactly same profile as i3.

I just bought an i3 REx in Los Angeles and drove it back 2000 miles to Iowa. No issues. I maintained 65-70 mph most of the way and wasn't even coded. Meant about 3 places where I dropped to 30 mph on passes, but follow a slow truck and no big deal. Worked well since it was mild temperatures (didn't need heat or AC much). I wouldn't recommend this, but it is possible, this would not have been possible in a Bolt EV in a reasonable time frame (the i3 took maybe 4 hours longer than a normal car due to lower speeds and 35 gas stops).

 

[graememwl]

...The recommended safety margin is 2-seconds. Yes, people drive that close, and no, they really shouldn't at speed. That's why they came up with the 2-second thing...people couldn't remember x car lengths at one speed, y at another, and so-on. It's easy to estimate 2-seconds by just counting when the vehicle ahead passes some reference, and then how long it takes you to cross it....

The 2 second rule has 1 second built in for driver reaction time. I know from regular experience that the ACC will react *much* faster than that. When a car slips into the gap between me and the car in front, ACC immediately slows to regain the gap.

That being said, I personally adjust the ACC distance based on traffic speed. Open freeway, high speeds, max distance. Stop-go traffic, min distance. But then, my wife says I drive like a Grandad - which I do... and I am

ACC has become one of my favorite features. I won't buy another car without it.

 

[jadnashuanh]

I think that anyone that has the ACC on their i3 has found situations where it doesn't always detect a vehicle anywhere as soon as a driver that is not asleep can. So, IMHO, it's still best to keep the following distance at that 2-second distance. Relying on technology is okay up to a point. The camera isn't as comprehensive as that plus say radar or lidar...some things can confuse it. It's just more comfortable and smooth to have a larger gap. That equates to better efficiency as well.

I haven't really tried to evaluate it, but does anyone know whether the i3's following distance varies based on speed, or is it a fixed distance, regardless. I agree that I've come to like it. I didn't opt for it in my last car, but it was in the package I wanted on the i3. I would prefer it on any new vehicle after having lived with it for awhile.

 

[viking79]

Although a 2 second following distance is recommended, I think anything 1 second or more is perfectly safe, if the driver is fairly attentive. The extra 1 second gives you more time to react, but 1 second is enough.

In heavier traffic I tend to follow at 1 to 1.5 seconds for greater traffic density. Given the number of people that follow far closer than that and don't get in accidents daily makes me think that 2 seconds leaves more safety margin than really necessary.

Agreed though, I definitely don't tailgate and get annoyed by the behavior, but 2 seconds leaves plenty of margin.