Search This Blog


Sunday, September 2, 2012

What Information Do You Want Your EV To Display?

A screen shot of the concept i3 drivers display. Nice and simple but where is my SOC?
We are living in an age where there is so much information available we can suffer from information overload from time to time. We have even created the acronym "TMI" (too much information) to quickly announce the information you have been presented with is more than you care to know about the subject. 

F-16 cockpit display
Automakers struggle with this also and are constantly trying to find the right balance of information that is displayed in their cars. With on-board computers constantly monitoring thousands of functions, they could easily display so much of the car's information that the display would look like the cockpit of an F-16 fighter jet. Although I'm sure a few people would like dozens of gauges and digital displays, most customers would find it overwhelming and so complicated that the information they want to see would seem buried amongst the useless technical data that few really care about. This was difficult enough with gas cars. Manufacturers have been working with the information displays on gas cars for a long time and pretty much understand what the public wants and how they like it displayed. However when it comes to EVs, I'm not so sure they quite yet understand what the prospective EV customer wants. 

I do understand the dilemma they have. Should they make the display look as much like it does on a gas car so the transition from gas to electric is easier? I think the majority of hardcore EV enthusiasts will say "No way!"  Electric cars are about the evolution of the automobile and the information displayed should also evolve.  In other words, they want more, they want as much as they can have. Then on the other hand I have spoken to people who worry they won't understand a whole bunch of new gauges like real time consumption measured in miles per kilowatt hour. Everyone understands MPG, but miles per kWh? Not so much.

Nissan LEAF drivers instrument cluster. Note the SOC bar graph on the right
After driving electric vehicles for about three and a half years now the single most important piece of information I want to see is the vehicle's state of charge or SOC and I want it shown front and center in a numerical value. Nissan made a terrible decision to display the LEAF's SOC with twelve bars like a gas gauge, each representing 8.33% of the cars stored energy(I assumed they were equal, but I've been told by LEAF owners they are not and the first few bars represent more energy than the last few- even more confusing!). Quick, tell me what percentage of the battery do you have left and how far you can go if you only have 5 of the twelve bars remaining? Most people can't without thinking and most everyone I have spoken to who has a LEAF absolutely hates the SOC bar graph. Please give us a clear numeric value for the state of charge and have it displayed all the time on the drivers instrument cluster. I don't want to have to search through options on the car's center information stack to get to it like I have to do with the ActiveE. (note: BMW gets a pass on the ActiveE because this is a conversion and they do have the SOC in a numeric display, just not on the drivers instrument cluster where it is shown using the existing gas gauge that the 1 series uses)

Multiple display settings of the Ford Focus EV
I have not yet driven a Ford Focus Electric, but what I've read about the instrumentation has been been mixed reviews. Some like the various screen views that display range and a 'brake coach' that evidently helps you use the regenerative braking to your best advantage. However most everyone seems to dislike the 'points' game that Ford is using to help the drivers learn to drive more efficiently. Evidently you start out with an estimated range, lets say 76 miles which is the EPA rating for the FFE. As you drive, if you drive efficiently and the estimated range goes up a mile you get a point and if you drive inefficiently and the estimated range goes down you lose a point. You also get butterflies for every point you earn. (yeah I'm not kidding, there is actually a butterfly display screen; what a great use of prime real estate - ugh) So while you drive you see if you are earning or losing points, like a video game. This is supposedly meant to help teach the driver to be more efficient so the car will go further. You want to go further? Slow down. Period, end of story. Of course there are other techniques like gradually accelerating instead of stepping on it from a standstill and finding routes that have less hills, but in the range game speed kills it's really that simple. Ford's use of these points and butterfly game is what I'd call finding a solution when there was really no problem to begin with. If they really wanted to have something that coached people to drive more efficiently it shouldn't include a points system and using up valuable space on the drivers information cluster with pictures of blue butterflies.

Recently Honda started leasing a converted Fit electric car to select markets in California. I happen to know a couple of the first Fit EV lessees as they were MINI-E lessees also. Peder Norby, Colby Trudeau and Matt Walton have all leased a Fit EV and all are very happy with it so far. They have posted pictures of the FIT EVs displays online and Peder sent me some pictures at my request. I do like how it displays the regained energy form regenerative braking. Neither the MINI-E nor the ActiveE display that information so I really don't know how much it's helping. I know it is, and I know the car is going further because of it, but without a gauge to let me know either how many kWhs the regen supplied to the battery pack or how many miles it's added to my trip. I have no idea how effective it is. I hope BMW doesn't drop the ball on this. I want to see this info on the i3. It's not the kind of info I need displayed all the time on a permanent gauge, but I want it there so I can view it at my discretion.

So what exactly do I want to see? Well I do want a lot of information, but I don't necessarily want it all being displayed all the time cluttering up the displays. I'd like a clean looking display with only the basic, necessary information on display all the time. Don't clutter up the displays with TMI, and please no leaves, butterflies or smiling polar bears. The other pertinent info can be called to the center stack info screen upon request. For the purpose of this post I am only talking about the information related to the electric drive, not navigation or entertainment related displays.  Here's how my displays would look if I could design them:

Main instrument cluster in front of the driver:
(This info should be shown all the time)

-Large MPH and SOC(a number, not a bar graph) display front & center.
-Battery temperature & outside temperature.
-Estimated remaining driving range.
-What mode the car is in (Normal, sport, Eco Pro, etc)
-Battery low warnings when applicable

Center stack display:
(This information could be on multiple screens, with user scrolling necessary)

-Power use/regen gained display with real time energy use and regeneration displayed in kwh's. 
-Trip information. Miles driven, consumption rate, kWh's used, kWh's regained from regen, average speed, time elapsed. 
-Historic information: All the information from trip info, combined with previous trips until it is reset. 
-Energy consumption breakdown: I'd like to know what percentage of my energy consumption broken down into three categories: how much energy was used by the electric drive motor, how much by the thermal management system, and how much by the other electrical devices like cabin heating, radio, lights etc
-Charging station locator
The ActiveE display is a 1 Series conversion just like the car. I am not a fan of the fuel-type gauge for battery state of charge. I want a numeric percentage of the battery SOC staring back at me when I drive my EV.
So that's what I want. Now let me know what you want! Please leave comments below and tell me what information you want for your ideal EV.


  1. There are so many things that would be great to have, but it results in clutter so I've listed just the top

    Center stack:
    Must have: MPH, %Charge remaining (current and expected when arriving at next way-point)
    Nice to have: Miles remaining (ideal and predicted based on last 10 miles of usage)
    Geek data: Temperature of drivetrain (battery, gearbox, inverter), outside ambient, inside cabin. Comparisons of WPM (Watts per Mile) usage based on GPS data from other users and/or previous travels on same road.

  2. As you mentioned, I don't want the console all cluttered up with too many gauges. Have all the information a geek would want like watt hours per mile and watt hours recaptured with regeneration available though on the info-center. I'd like that info available in ten minute intervals so I can see the past half hour of driving efficiency displayed in three segments.

  3. Here's my selection - in order:
    1. Large round analog MPH/KPH gauge (Active E is a fine example)
    2. Remaining driving range (numerical)
    3. Distance and expected arrival time to next/final waypoint
    4. Battery charge (analog like the AE, not a numerical %)
    5. Clear engine ON/OFF indication - no good examples exist - a highly unmistakable change in display color accompanied by an unobstructive audible
    6. Charge/discharge gauge - On the AE, this is the "charge, ready, e-drive", which is too basic. I'd like to more information overlaid on this gauge to include a peg for consumption rate history (this trip and average since last reset)
    7. Operating mode (Sport, standard, eco)
    8. Current time of day (I'd prefer analog, but digital is ok) and today's date
    9. Outside air temp (degrees F/C)
    10. Battery temp (Optional - show only if an issue)

    With the items above displayed, it would not be necessary to depress the "BC" button.

    Other suggestion: It be nice to cut back on the most of the annoying beeps, such as when you have the door open and the key inserted or when you drive without your seatbelt. It's too loud too.

  4. miles per kWh
    Battery state of charge in % not a guess-o-meter like LEAF

    Estimated remaining miles but give me three numbers (if I drive really efficiently, normal driving, and if I drive fast and non-efficiently) I haven't seen anyone do this and I think it would be useful especially for virgin electric vehicle drivers.

    I like the idea mentioned about showing how much energy was captured by the regenerative braking. Hadn't thought of that before but it would be a welcome addition.

    Current energy output, I'd like to be able to view how much energy the car is using as I drive and could even measure it at different speeds and elevations. It would be very useful tool


  5. I like the way it is set-up now in the ActiveE. Give me an analog dash- maybe a few computer read outs but be subtle and all the juicy tech info on a center LCD. I like to drive not play NASA

  6. You mention both "the prospective EV customer" and "the majority of hardcore EV enthusiasts". The two groups have different concerns and interests. Mass-market EV adoption won't be among today's hardcore enthusiasts, so the information and its presentation must be attractive and useful to prospective and non-enthusiast drivers. But it would be disappointing to not accommodate the existing user base of enthusiastic, technologically knowledgeable early adopters.

    Since the three available display areas in a car (instrument cluster, dashboard, and head-up) can be displays under software control, why not give the user control over what to display and how to display it? Common consumer information displays, such as phones, tablets, laptops, and desktop computers, let the user select what, how much, and how to display. Let's not get into a religious argument about IOS vs. Android vs. Mac vs. Windows vs. Linux, but I choose my products and platforms based largely on how much control I get over the information displayed and its presentation. Automotive telematics should be no different.

    Here's the extreme of flexibility: Run Android on the displays, make all* the information available, publish APIs and some sample apps for accessing that information, and provide some sample collections of those apps and widgets for different modes like day vs. night, highway vs. parked, etc. The sample apps and modes should provide adequate information, with a presentation that's suitable for a mass-market driver, the 90+% who are unlikely to learn how to customize anything.

    *What is all the information? Start with full access to OBD-II and the navigation and battery management and entertainment systems. Provide Internet access so the app can reach the Google Geo and ChargePoint driver APIs.

    Examples of simple customization of the presentation, even though it's the same information: I like my heading data presented in both digital (322 degrees) and compass rose form (selectable north-up or forward-up), but my wife likes more general text (NW). Someone might want speed or altitude or kW flow (in or out) in digital form, but someone else wants a (graphical representation of a) needle on a dial, but someone else wants that needle+dial overlaid on a graph showing 5-, 15-, and 30-second averages, along with 1st and 2nd derivatives.

    More sophisticated access to the on-board and cloud APIs would provide route advice based on state of charge, ChargePoint locations and availability, elevation change along the route, and both live and expected traffic, based on the driver's weighted preferences.

  7. Great blog post, Tom! For what it's worth, Renault announced earlier this year that they are going to open up their cars for third party developers. That would go a long way to satisfy the need for more information and better and more sophisticated presentation.

    I have seen a number of new EV drivers here and in the Leaf community, and I'm relatively new to driving one myself. It's surprising how quickly you can used to new metaphors. MPG figures seem distinctly antiquated now, and the MPGe rating EPA came up with is perhaps only interesting when buying an EV.

    I would vote for displaying total usable capacity in kWh in addition to energy economy (or consumption) on one of the gauges. Ideally, it would be on the main screen, but if it was an option one could select, that would be great too. Traditionally, SOC is shown as a percentage, and that would be another key piece of information I would hope to see on the dash.

    That said, we probably won't get around a guess-o-meter or a distance-to-empty gauge. I have seen a number of drivers in the Leaf community that use the DTE daily and believe it to the letter (or digit). Many of them don't want to bother doing mental math, especially if they don't need to push the limits of the vehicle.

    Having a DTE gauge that's reasonably accurate and does not inflate or deflate range estimates like the Leaf does would go long a way to help. Personally, I would like to see a guessometer which uses the consumption rate and multiplies it with usable kWh. You could control the integration period by resetting the consumption gauge, and we could have two of those, like is often the case with trip meters, since it's an important piece of information.

    It would be good to indicate instantaneous energy use and its impact on range. The Volt does that with its floating ball, which is pretty clever. The Leaf has a detailed energy consumption screen in addition to the silly eco trees. Another possibility is to color the range estimate green or red depending on how you are presently driving. This would give you feedback and tell you if you were losing range faster or slower than anticipated. Another possibility would be to show an estimated range gain or loss based on current driving. The Leaf does something similar when you turn on A/C or the heater. It tries to predict how much your range would be reduced if you ran the accessory at the present setting all the way.

  8. Thank you George! I do think they will certainly have a 'distance to empty' gauge for certain. for the foreseeable future I think all electric cars will. Especially when the ranges are so much less than they are for gas cars. However once the battery technology advances to the point where we routinly get 300 or 400 miles on a charge then I think people will worry less about how far they can go before they need to plug back in. I don't mind the Guess-o-meter as long as it works! I've found the state of charge meter on the ActiveE to be pretty accurate, especially when you compare it to the on on the LEAF. The state of charge meter HAS to be accurate.

  9. Bob Sut said it best, make the display changeable so you see what's most important to you.

    By the way the LEAF is not 8.3 % per bar, many of us have lost 1 BAR of capacity and it's 20% !! each bar is not linear, so it's very hard to tell what they really mean.

    The x point that the gid meter and prototype SCAN GAUGE show for battery capacity is real valuable. The temperature of the battery is also valuable if you don't have liquid cooling.

    Mile/Kw (make the kilometers, we need to change to metric!
    Capacity remaining. Regen energy would be super like Tesla has, in fact make my next EV a Tesla whitestar (I call it Tesla B for basic , that is coming out in 2014!

  10. Unknown: Thanks for chiming in here. Yes, Somebody else pointed out to me that the LEAF's bars don't all represent the same amount of SOC. That's CRAZY! They made it even more confusing! I really don't like the LEAF's state of charge display or the guess-o-meter. They really did a poor job on these very important displays if you ask me.

  11. Hmm , instead of growing trees like in Leaf i want girls stripping on my dashboard as i drive more "greener" (-:

  12. I would like the car to maintain a database of all the ODBII parameters every five or so seconds, and to present this data as a web page accessible via wifi or bluetooth. You would be able to monitor whatever you wanted to on the move using a smartphone or iPad, and when you get home the car would be accessible via the same data link to your desktop system for a more in depth analysis when you are not driving.

    I have a Leaf and am somewhat disappointed by the data sent over the cell phone data link and the poor software available on the Nissan and Carwings sites. At a minimum give me the raw data and I and other users will quickly come up with applications to display meaningful pictorials.