REX fuel consumption

[Zwerius]

Hello,

Was just wondering what your consumption values are.
I recently found out, that the total distance and the electrical driven distance can both be found in the i3-app.
Fortunately I kept track off the amount of fuel I've added in the i3 (from the start in March 2014).
Total distance = 38354 km, electricaly driven distance = 37522 km.
So driven on gasoline (through REX) was: 832 km.
Total amount of gasoline used was 31 litres.
So specific fuel consumption was 832/31=26.8 km/litre or 3.73 litres/100 km or 63.5 miles/gallon
Although I rearly drive faster than 80 km/h (=50 miles/h) and almost never faster than 90 km/h (=56.25 miles/h) it still seems unbelievable to me that this fuel economy has been achieved.
Anyone with similar values?

 

[alohart]

I think that your unrealistically high fuel efficiency is due to iRemote's inaccurate record of the total distance driven purely electrically and with REx assist. REx owners who have measured the fuel efficiency of the REx engine have reported fuel efficiencies of ~6 l/100 km (~40 mpg).

 

[Zwerius]

But how did they measure it ....?

 

[bwilson4web]

Hi,

My metrics, fuel consumed during 100% REx operation, measured US gallons at pump divided by miles at a cruise control, constant speed:

• 45 MPG @35 mph - standard day
• 44 MPG @55 mph - standard day temperatures at night
• 40 MPG @65 mph - standard day temperatures at night
• 39.6 MPG @~67 mph - Labor Day weekend 2016, to and from Huntsville AL-Stillwater OK, mixed AC, with wheelchair on carrier
• 36.4 MPG @65 mph, AC, +90F temperature without wheelchair on carrier
• 36.1 MPG @65 mph, AC, +90F temperature with wheelchair on carrier
• 32 MPG @75 mph - mid-80s, loses 20% SOC with each tank

Bob Wilson

 

[TOEd]

Different measures may be explained by Imperial vs US gallons. 4.54 l/ImpGal vs 3.8 l/USGal. In Canada I always use Miles per ImpGal. Results are 20% higher which makes me feel better.

 

[Zwerius]

I did the calculation in km/litre and then recalculated it to miles/gallon, using 1 gallon = 3,78541178 litres

 

[bwilson4web]

Truth be told, I've moved towards another metric that allows me to share the comparative cost per mile for both electric and gas operation:

• $0.25/10_miles - electric ($0.10/kWh)
• $0.61/10_miles - gas-only on highway ($2.40/gal)

I am using local utility and gasoline prices so your values will differ. But in my market, this is what it costs to go 10 miles. Folks can then calculate in their heads how much it will cost to drive say, 100 miles, $2.25 electric or $6.10 gas. Knowing their local price of gas and what it is costing them today, these drive home the message very quickly. FYI, 10 miles is a typical, USA commuter distance or round-trip to a grocery store.

Bob Wilson