Running on ice

Just playing around with my new to me 2014 i3 rex. Coded and ran all day in hold charge at about 70%. Heater on most of the time. Only difference really is more frequent gas stops other than that has the power of the electric motor and convenience of an ice car.
Average 60 mpg.
One odd thing is that most of the time the engine would shut down at stops which is normal, however there were several times when the engine would keep running at a stop just wondering why that is.

Nice findings! How did you calculate the MPG figure? I'm also curious what type of fuel you used (octane, ethanol content, etc.).

If the depth of discharge from the held state of charge reaches a certain threshold, than the computer disables the start-stop functionality of the engine- this allows it to build up the charge again when power demands are low. I've found that you have to give the system a few % of SoC to play around with, but that as long as I'm driving fairly reasonably (i.e. not driving 85MPH and passing everyone on the freeway), it's able to keep the SoC up. Driving up a steep hill obviously drains the battery faster than what the REx can supply, but eventually it'll work it's way back up. While I've had my car for a little over a month now, during the past couple days is when I've really been testing REx functionality- I plan on using it soon to make a 350mi one way trip that has zero CCS stations there or along the way.

Wow! 60 mpg is awesome. Closest I got is 45 mpg and I was thrilled. You had the heater on and still managed to get 60 mpg is amazing.

I have driven in ICE mode and have never had any issues whatsoever. Even on the 5 Fwy grapevine pass the car didn't slow down a bit. On normal fwy driving I have yet to tell the difference between ICE and EV but I don't keep an eye or ear on the minor things and I am sure there is a difference.

TheMK said:

Nice findings! How did you calculate the MPG figure? I'm also curious what type of fuel you used (octane, ethanol content, etc.).

If the depth of discharge from the held state of charge reaches a certain threshold, than the computer disables the start-stop functionality of the engine- this allows it to build up the charge again when power demands are low. I've found that you have to give the system a few % of SoC to play around with, but that as long as I'm driving fairly reasonably (i.e. not driving 85MPH and passing everyone on the freeway), it's able to keep the SoC up. Driving up a steep hill obviously drains the battery faster than what the REx can supply, but eventually it'll work it's way back up. While I've had my car for a little over a month now, during the past couple days is when I've really been testing REx functionality- I plan on using it soon to make a 350mi one way trip that has zero CCS stations there or along the way.

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You should be fine. I have driven thrice to the bay area from Los Angeles. I used to go on the 101 fwy as it has pretty good fast chargers along the way. But on my last trip I decided to go on the 5. I held SOC at 75% and drove close to 300 miles on ICE at a steady speed of 75 mph. I carried 2 gallons in my frunk but never had to use it as there are plenty of gas stations along the way.

Unlike all plug-in hybrid cars, and even the Chevy Volt, the i3 REx's gasoline engine is not physically connected to the wheels at all. When the ICE is running, it is solely driving a generator to send electricity to the high-voltage system (to charge the battery, and/or to run the drive motor.) Some plug-in hybrids can run this way, but this is the only way the i3 REx works.

In default behavior or range-hold, it runs solely long enough to charge the battery up to the desired level. (6% in default North American usage, or whatever level the battery is at when you engage range-hold.) If you stop at a stop light, and the battery is below that level (say you just climbed a steep hill,) the ICE will continue to run until the battery reaches that level.

One other big thing to note - the REx operates at one of two speeds - "maintain battery" or "maintain battery plus provide motive power." If you use it only in range-hold, you'll only ever have it in the (much quieter) "maintain battery" level. If you use it in regular mode, and try to use a lot of power (accelerating on the freeway up a hill,) it will kick in to high-RPM mode, which is *REALLY* loud and annoying. (Batteries can't provide as much power when low on charge, so when the battery is low, it may not be able to provide enough juice as you're asking for - even though it technically has enough *charge* to get you up it, hence the addition of extra RPMs from the REx to provide that extra power.)

To put it another way, there is no ICE mode in the i3...you are ALWAYS running on electricity. Now, it could be coming from either/both the battery or the REx's generator, but it's still ALWAYS running on electricity.

The REx was added as a sales tool to help overcome range anxiety. If they really wanted you to be able to use the car all the time in any conditions, the engine would be larger as would the fuel tank. Given the stated mission of the car, it is a tribute to its design that it CAN be used for longer trips. They come with some issues. Many may find them acceptable, the mainstream probably won't. IMHO, the i3 REx is not a no compromise substitute for a conventional car, but you may find the disadvantages small enough to use it that way. Your money, your choice. Stress the output, and you will have more compromises.

Until CCS is as readily available and reliable as a gas station, IMHO, the best choice is a good hybrid with enough battery capacity to do your 'normal' running around, and the convenience of long-distance travel to anywhere with no compromises if you only can support one car. Right now, the pickings are slim, but slowly improving.

I only use premium gas that day I filled up twice first reset trip to zero then just divided miles driven by the gas I put in to fill got 60 mpg. Engine was running pretty constantly except when stopping so I think it's fairly accurate.

I'm going to drive this way a few more times to get a better average. I know it's just charging the battery but that's my point. I'm able to keep a constant charge and run on gas if I want to with all the benefits of the electric power.

The only restriction is the small gas tank but if you need to make an extended trip you can without having to park a few hours to charge. I look at it the same as riding a motorcycle, its about the same range and mileage. People make extended trips on bikes all the time.