GOM range from 66 to 71 mi

Hi,

Waiting on replacement Tesla tires, I've been using our 2014 BMW i3-REx that had been sitting unused. Air the tires up, run the maintenance REx cycle, and off around town.

Initially the Guess O Meter (GOM) said it had ~66 miles range. But as I used the car daily, the GOM increased to as high a 71 miles. Then a cold front arrived in Dixie yet if pre-conditioned, it is coming back to ~71 miles.

This is a great car and perfect as a Tesla backup. My Tesla tires are coming from Tire Rack and there have been shipper problems. Regardless, the BMW i3-REx is working great.

Bob Wilson

I'm on my second i3S Rex and I love it! It gives me more joy and enjoyment than mot 6 figure cars I have owned. My G-o-M goes up and down with temps too. Warm weather gives my electric range up to 160 miles and cool or cold weather can drop it down to 136-140 miles.

My Fiat 500e was the same way, I saw swings from 70 miles range to 110 miles range based on temperature. It was pretty crazy.

[CAUTION]

Using an Electrify America, 150 kW charger, it looks like the charger failed to stop when the battery reached full charge. It stuck at 99% and continued to charge. So I had to manually stop it. The GOM showed 77 mi at the end. Once on the road again, it quickly dropped to 72 mi and thereafter showed normal discharge characteristics.

INVOICE:

01/14/2021 11:03:05 AM

Walmart 661 (Athens, AL)
1011 US Hwy 72 E
Athens, Alabama 35611
Charger #110028-04
Connector #2

Total paid: $8.67
Session ID: 558844
Transaction ID: *********

Charging pricing: $0.00/session + $0.16/minute (plus tax, if applicable)
Charging cost: $8.67
Discount: $ 0.00
Idling: $0.00 ($0.40/min)
Sales tax (0%): $ 0.00

End state of charge: 99%
Energy delivered: 16 kWh (started 6 mi on the GOM)
Max charging rate: 49 kW
Charging time: 00:54:13


Bob Wilson

The vehicle tells the CCS (or EVSE) when to stop charging, so I don't think you can blame the CCS unit (all it has to do is break the interlock signal). FWIW, 99% isn't full, and once it gets near full, the charging rate can slow down considerably and trickle in those last few watts, which is often why it's recommended to only go to 90%, especially if you're paying by time versus just KwHr. The moderately high DCV level you might temporarily get when using a CCS unit could result in an artificially high GOM until things stabilize after it's removed. So, at least for me, nothing seems out of whack.

jadnashuanh said:

The vehicle tells the CCS (or EVSE) when to stop charging, so I don't think you can blame the CCS unit (all it has to do is break the interlock signal). FWIW, 99% isn't full, and once it gets near full, the charging rate can slow down considerably and trickle in those last few watts, which is often why it's recommended to only go to 90%, especially if you're paying by time versus just KwHr. The moderately high DCV level you might temporarily get when using a CCS unit could result in an artificially high GOM until things stabilize after it's removed. So, at least for me, nothing seems out of whack.

Click to expand...

Thanks! This is what I figured but I had nothing in the cabin showing amps, volts, or kW. On the Electrify America display, I didn't see any of these either. Just I got anxious when GOM showed over 72 mi so I stopped it on the big display.

When I got home, the maximum GOM showed 77 mi! It is as if the Electrify America CCS-1 charging reset or enable more aggressive battery management. Casual observation suggests that after the first mile, the GOM goes down in proportion to the actual miles. I've not done or plan on a formal study but that was my impression.

Bob Wilson

The full, L2 charge is showing 77 mi on the GOM. But these are shallow miles as in about a one mile, it falls to 72 mi. Thereafter, the GOM and trip miles follow each other.

Speculation but it looks like the Electrify America 'over charge' may have broken an earlier barrier to full charge.

Bob Wilson

bwilson4web said:

Speculation but it looks like the Electrify America 'over charge' may have broken an earlier barrier to full charge.

Click to expand...

I doubt that any overcharge occurred because an EV tells a DC fast charger its battery pack's charge level which is displayed on the charger's screen.

Also, as shown below, with a 60 Ah battery pack, the DC charging power begins dropping at a charge level of ~60% down to no more power than an AC Level 2 charge at ~90% charge level. This makes DC fast charging to a high charge level expensive when charged by the minute rather than by the kWh and so slow that charging to 100% makes little sense unless full range is needed.