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Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 9:55 am
by TomT
Agreed. Keep it simple and inexpensive! Let Phil build one that does everything under the sun (and with a commensurate major increase in price therefore). :lol:

GregH wrote:Wow.. you engineers really like to make this complicated! what's the opposite of K.I.S.S.?
I'm going Steve Jobs ZEN on this thing, trying to make it simple and intuitive. Things that really are a percentage (like SOC) will be displayed as such, all else will have appropriate units.

Re: *NEW* Dash Display for Leaf; I'll take one

Posted: Mon Apr 29, 2013 10:26 am
by Stoaty
DanBaldwin wrote:I vote for uncooked GIDs. I don't mind if they are blanched, but I prefer they have at least a little crunch.
Do you insist that they be warmed up a bit in the microwave, or are you OK getting them straight from the fridge?

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 1:43 pm
by TonyWilliams
GregH wrote:
TonyWilliams wrote: show 0% and 0 miles.
Maybe we should get rid of gallons for measuring gasoline and just assume all cars have 10 gallon tanks.. then we can display remaining fuel as a fixed calculated percent like Gid% or Gid2% (or whatever). Gas stations could display % added... :lol:

Well, you're not winning this part of the issue! Ten gallons obviously do not account for cars that have 8 or 12 gallon tanks. But Full and Empty covers any size gas tank. I don't know too many dash gas gauges that don't show a simple "F" to "E", or "1" to "0", or even no nomenclature whatsoever.

The mass market doesn't care how many gallons or kWh are going in the car. They only want to know if it's full and how far they can go.

Not all Leafs charge to 281.. many don't even come close anymore and who's to say a 2014 Leaf might charge to 320 Gids? The only truly common unit is the raw uncooked Gids.

True, which is why I don't want solely SOC%. If the car can no longer store 281 Gid, I want that reflected in the % available to the end user. It lets the end user know the car won't go as far as it did at 100%, and they'll know about how much less quite easily. We don't have 320 Gid cars.

Rated Range would reflect the % available.

the pack voltage graph is extremely helpful down in the low Gid range to see how much juice you really have left. The old RAV4-EVs had this and the turtle mode was tied directly to it.. As long as the voltage was high enough the turtle stayed away..

I'm not suggesting anything different to pack voltage.

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 3:13 pm
by GregH
I for one would welcome gasoline cars that told you how many gallons of gasoline remained in the tank (that is, if I drove a car that used gasoline). When we did the EDrive plug in Prius I measured exact gasoline consumption down to 0.001Gal and it was kinda cool for those of us who drove close to the edge (not as big a deal to run out of gas if you still have a few kWh of juice in the battery.. I used to try to get 1000 miles on a tank).

If you want a fuel gauge like a gas car, use the precision SOC mode. If you want a measure of remaining energy, use the Gids mode. If you'd like a higher precision version of Gids, I could provide Ah remaining based on the Ah capacity and precision SOC I suppose.. I'll have to think about that. There's also a number in the group 1 data which seems to be a 4 digit health number in percent although it doesn't exactly scale with the Ah capacity so we're not totally sure. But it sounds like SOC*health is what you're looking for... a unit-less number that would be ~1.000 on a fully charged brand new car. As long as there are no constants involved, I'm open to suggestion.

For reference.. 5 cars that were looked at with the above numbers (Ah Capacity and health %) came up as follows:
66.0198Ah 100.79%
62.0904Ah 93.45%
61.2179Ah 91.81%
61.9985Ah 93.27%
49.3443Ah 68.56%

Those are all raw numbers from the Group 1 data.. all I added was the decimal point.

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 6:40 pm
by mkjayakumar
Give me raw Gids and everything else Tony said for calculating remaining range.

281 Gids should be 84 miles left
7 Gids should be 0 miles left
So a gid represents 84/274 miles or around .3 miles, or 3.2 Gids to a mile.

You can't get more accurate and less confusing than that.

Thanks
Jay

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 8:15 pm
by surfingslovak
Image
GregH wrote:If you'd like a higher precision version of Gids, I could provide Ah remaining based on the Ah capacity and precision SOC I suppose.. I'll have to think about that.
Would it be possible to display stored kWh, similar to what Phil had planned for LeafScan? Jim's WattsLeft shows miles remaining to a certain marker (LB, VLB, turtle) based on a set of different energy economy figures. I applaud all the great work you, TickTock, Turbo3, garygid and others have done recently on the CAN bus hacking front. Please don't view the feedback on this thread as criticism. It's more like a brainstorming session in my mind. Personally, I was always in favor of using a smart phone or a tablet as front-end. That's what I tried to impress upon Turbo3 when he took an interest in building a meter last year. I mentioned that on MNL as well. That said, a significant population of owners will continue to prefer a permanently-installed dedicated device with its own display, and it's definitely worth the effort to design it right. I don't think that the LEAF community would necessarily need another WattsLeft, which I personally consider very feature rich. I really appreciate the slim design of your meter, and its price point. It's good to have some options.

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 10:01 pm
by Nubo
GregH wrote: Not all Leafs charge to 281.. many don't even come close anymore and who's to say a 2014 Leaf might charge to 320 Gids? The only truly common unit is the raw uncooked Gids.
Agreed but I'd take it one more step. I don't understand the penchant for synthetic units. What's wrong with kWH? When we talk of efficiency it is in terms of watt hours per mile or miles per kWH. When we measure wall useage it is kWH. I imagine I could get used to Gids but why not use a unit that is not LEAF-specific?

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 11:05 pm
by garygid
Primarily because we have to guess at the value of kWh.

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 11:23 pm
by surfingslovak
garygid wrote:Primarily because we have to guess at the value of kWh.
Yes, we can only guess the value of usable kWh. Could this be the primary reason why Phil decided to show stored kWh in his LeafScan prototype instead? That said, we know that each Gid is about 75 Wh usable energy on average. Also, in a similar scenario, Tesla decided to show ideal miles in the Roadster, even though they can only make a best guess about both the usable capacity and energy economy.

Re: *NEW* Dash Display for Leaf

Posted: Mon Apr 29, 2013 11:56 pm
by DaveEV
I also like the idea of reporting "rated miles" like Tesla does, but why mess with gids at all (with it's unknown units and known fluctuation with temperature) when we can get the Ah capacity of the pack from the car?

We know a new car reports around 66 Ah and will drive 84 miles to turtle at 4.0 mi/kWh. We also know that using the car's reported SOC the car should read 95% when fully charged and stop moving around 2.5% SOC.

Something like this:
Rated range remaining = Reported Ah / 66 Ah * 84 mi * (Reported SOC - 2.5) / (95 - 2.5).

Using thimel's data reported in another thread, his rated range (if I did the math right) would be 73.4 miles in his first pic and 5.1 miles in his second pic.