LeafDD - Dash Display for Leaf

[GlennD]

I agree the posts are fragile. When I changed out the fat cable I snapped one off. I was able to epoxy it back though.

Since the back is open maybe something like hot glue would hold it while still be removable.

 

[kieranmullen]

I want to buy one!

 

[Paqo]

How do you like my way of finding the right place for DD display

 

[lorenfb]

Hi Greg,

On the first page of the LeafDD which displays voltage ticks (the 1st being 340) also indicates the charging
current (starting from the right) above the voltage ticks. Or is this, though, really instantaneous kW based on
this statement from the LeafDD guide?
"Above all of this is the instantaneous current draw (or charge) to the battery. Discharge grows from the left side,
charge grows from the right. The photo shows my 2012 charging at 3.3kW.".

So is the display indicating instantaneous charging current (amps) or instantaneous charging power (kW)?

The 1st tick appears to be offset from the right of the last possible right display segment which would be
330 if it were displayed. The charging current (or kW) appears to begin from this far right point. Given this,
what can one assume as the charging current (or power) between ticks? When charging my Leaf at 5kW,
the indication is about half way between the 330 (if it had a tick) and 340.

Thanks for your insight.

To answer my own question:
The displayed data are in kW (power), i.e. the LeafDD guide is in error. Or if one likes the other units,
then it's HP (horsepower). So each dot on the Leaf instrument cluster display represents about 10kW
or about 13 HP. Since my Leaf's average mileage is about 5 miles/kWh, at 50 mph the Leaf is using
about 10kW (13 HP) or just one 'dot' on the display. Obviously the displayed 'dots' don't linearly
represent power.

 

[Stanton]

How do you like my way of finding the right place for DD display

I like it! Details please?
Looks like you removed the airbag lights/display...what did you do with it...and how about cable routing?

 

[Paqo]

How do you like my way of finding the right place for DD display

I like it! Details please?
Looks like you removed the airbag lights/display...what did you do with it...and how about cable routing?

Actually it's hanging behind console as I found it not too much needed
and it is very easy to route cable behind console
I have used small piece of plexi glass - I used hot gun glue
DD unit fits perfectly behind.
I also solder extra switch and I have place it under console so it can be almost not visible.
And here is the photo story ....

 

[DaveEV]

How do you like my way of finding the right place for DD display

Nice work!

 

[Stanton]

How do you like my way of finding the right place for DD display

I like it! Details please?
Looks like you removed the airbag lights/display...what did you do with it...and how about cable routing?

Actually it's hanging behind console as I found it not too much needed
and it is very easy to route cable behind console
I have used small piece of plexi glass - I used hot gun glue
DD unit fits perfectly behind.
I also solder extra switch and I have place it under console so it can be almost not visible.

I wondered about the LeafDD switch: can't really work without it. I also see you did some CAN cable 'stripping'? Now that I've glued the LeafDD cover on, I'll have to think about whether or not it's worth doing any mods to it's wiring...

 

[Paqo]

DD is using only 4 wires from the cable so I found it not needed to use such a thick cable - but it is your choice
and I moved the button on the bottom of console (close to 12V inlet) that it is still accessible (but not visible )

 

[GregH]

How do you like my way of finding the right place for DD display

Nice work!

Very nice indeed!

btw, the power graph on the top of page 1 is actually just battery current, not actual calculated power.
The stock LeafDD never calculates power (V*A) although I have a version that ditches the Gid% option for a big power (kW) number.
The battery current from the car is only 0.5A resolution (lame!) but oversampled at (I think) 100Hz.. so the LeafDD does a little averaging to get a faux 0.1A resolution for the page 2 number.
It looks from the code like the raw 0.5A resolution number is shifted right twice (ie /4) and then either positive or negative graphed from the right or left side for the page 1 graph.
So the screen is 128 pixels wide thus a max current of 256A at 2A per dot.

 

[lorenfb]

How do you like my way of finding the right place for DD display

Nice work!

Very nice indeed!

btw, the power graph on the top of page 1 is actually just battery current, not actual calculated power.
The stock LeafDD never calculates power (V*A) although I have a version that ditches the Gid% option for a big power (kW) number.
The battery current from the car is only 0.5A resolution (lame!) but oversampled at (I think) 100Hz.. so the LeafDD does a little averaging to get a faux 0.1A resolution for the page 2 number.
It looks from the code like the raw 0.5A resolution number is shifted right twice (ie /4) and then either positive or negative graphed from the right or left side for the page 1 graph.
So the screen is 128 pixels wide thus a max current of 256A at 2A per dot.

Since the voltage is essentially constant, one can also consider that graphic as representing
instantaneous power (kW) or instantaneous HP. That graphic basically 'follows' the Leaf's
display graphic of power as one might expect since;
Power (kW) = Voltage (constant ~ 395/385) X Current (varying based on load or regen).

"So the screen is 128 pixels wide thus a max current of 256A at 2A per dot."

So when cruising at about 45 mph the display is about 10% of full scale (256 amps) or about
26 amps. Assuming a voltage of 390 would yield about 10kW or about 13 HP, which is also
one dot on the Leaf's power display. This somewhat correlates with the input power one might
expect from the Leaf's rolling resistance and drag (minor at 45 mph).

 

[GregH]

Since the voltage is essentially constant, one can also consider that graphic as representing
instantaneous power (kW) or instantaneous HP. That graphic basically 'follows' the Leaf's
display graphic of power as one might expect since;
Power (kW) = Voltage (constant ~ 395/385) X Current (varying based on load or regen).

"So the screen is 128 pixels wide thus a max current of 256A at 2A per dot."

So when cruising at about 45 mph the display is about 10% of full scale (256 amps) or about
26 amps. Assuming a voltage of 390 would yield about 10kW or about 13 HP, which is also
one dot on the Leaf's power display. This somewhat correlates with the input power one might
expect from the Leaf's rolling resistance and drag (minor at 45 mph).

I agree the current is a good approximation of power even though not technically the same.
As you note by the little graphic notch just below the current meter on the right (above the temp)
the pack voltage does move with current (and of course SOC) so I don't know that I'd say voltage
is constant.. but at least close enough for your purposes.

 

[lorenfb]

Since the voltage is essentially constant, one can also consider that graphic as representing
instantaneous power (kW) or instantaneous HP. That graphic basically 'follows' the Leaf's
display graphic of power as one might expect since;
Power (kW) = Voltage (constant ~ 395/385) X Current (varying based on load or regen).

"So the screen is 128 pixels wide thus a max current of 256A at 2A per dot."

So when cruising at about 45 mph the display is about 10% of full scale (256 amps) or about
26 amps. Assuming a voltage of 390 would yield about 10kW or about 13 HP, which is also
one dot on the Leaf's power display. This somewhat correlates with the input power one might
expect from the Leaf's rolling resistance and drag (minor at 45 mph).

I agree the current is a good approximation of power even though not technically the same.
As you note by the little graphic notch just below the current meter on the right (above the temp)
the pack voltage does move with current (and of course SOC) so I don't know that I'd say voltage
is constant.. but at least close enough for your purposes.

For the most part, as stated before, the voltage varies little (5-8%) compared to how the load/regen
current changes. So for all practical proposes, that graphic is a good representation of power.

 

[garygid]

Isn't a variation of the DD used as the Bursa controller?

Assuming that somebody wants to do the Bursa modification,
is a controller still available, and what price, please?

Thanks

 

[JeremyW]

Yes. It listens to the existing on board charger and sends messages to the Brusa all over the EV CAN bus. Probably should look towards porting control to the CANary or another device. The CAN commands are relatively simple. See: Brusa NLG513 CAN Command Matrix

 

[lorenfb]

The LeafDD is useful to determine another proxy for battery condition.
A typical battery condition evaluation is a load test, which basically
measures the output impedance of the battery.

Since the LeaffDD can display simultaneously both the Leaf's instantaneously
battery voltage and current, the instantaneous output impedance can then be
determined. Obviously, the output impedance will vary as the battery becomes
discharged. As a result, any evaluation over time should be done at the
same charge level of the battery. This method is not to be considered as a
rigorous and robust calculation of output impedance, but as a quick and simple
method to evaluate the Leaf's battery condition over time.

As an example:

Mileage - 7600, Charge Level - 50Ahr, Temp - 76 deg, Speed ~ 30 MPH
Load ~ 64 amps (25% of FS from acceleration), Voltage Change ~ 4 volts

Then Z (out of battery) = 4 volts / 64 amps ~= 62.5 milli-ohms or 16 mhos

 

[jlsoaz]

Hi all:

Questions for Greg, not urgent, but figured I'd post them here also:

I was filling out an update to the PIA Leaf Battery Survey and decided to use my LEAFDD in order to fill in the gids and aH. On the survey, they have something called SOH (state of Health%) and Hx (?). On the LeafDD there is an "H" number, but I was not sure whether this corresponded to one or the other. So, in the end, I left these two blank on the survey.

I also noticed (haven't used the LeafDD that much) that when I was charging using my Clipper Creek, which I believe maxes out at 7.2 kW, that the Voltage read about 249 and the amps read about 33. I emailed Greg, but will also just ask here.... are these the numbers of the charge being provided to the vehicle or are they the numbers for the actual charging that the vehicle is accepting? I had assumed that my 2012 Leaf could not accept more than 3.3 kW, but is that assumption wrong?

 

[JeremyW]

H on the LeafDD is "Hx" everywhere else.

They are the voltage and pilot current capability as seen by the on board charger. The 2011-2012 models will charge at 16 amps at 240v as long as the pilot is 16 amps or greater. At 208V it will draw around 18 amps.

 

[jlsoaz]

H on the LeafDD is "Hx" everywhere else.

They are the voltage and pilot current capability as seen by the on board charger. The 2011-2012 models will charge at 16 amps at 240v as long as the pilot is 16 amps or greater. At 208V it will draw around 18 amps.

Ok, thx.

 

[lion]

hi Greg,

What would be involved in showing the data in 'mirror', so the LeafDD could be used as a Heads-Up Display (besides sending it back to you)? I would be willing to pay for the modification.