DIY Electric Car Forums banner
21 - 36 of 36 Posts

Registered
Joined
3,538 Posts
Converting their tach to a speedo doesn't work. Clearly, there's a stack of metal plates in China waiting for white silkscreen.

So much awful there.

I'd use a tach plate for a Speedo, marked accordingly

Battery temperature needs a red zone above 70C (or whatever your cell freakout temperature is) unless you use tricolor LEDs in the holes.

Battery SoC needs a red at 10% unless tricolor LED in hole.

Amps needs green to max continuous, yellow for peak, red for yikes.

Need an outlet temperature for DU cooland/oil and inverter outlet coolant temperature.

I prefer the cat pee yellow vs bird poop white for the lettering/markers, but that's just a matter of one of us lacking personal taste 馃槀
 

Registered
Joined
124 Posts
the battery temp scale could probably be half of that. If your getting up to 100c in the battery, its probably already on fire.
You've got the whole gauge, may as well use it.

I like the amps gauge though, Thats a good one
 

Registered
Joined
3,538 Posts
According to tests from NASA, an 18650 cell doesn't light off until 120C on its case.


If you're trying to hit max rate charging, you're running the cell cases at 45C-50C for at least a dozen minutes. Half scale would not work, as you'd get zero visibility to a creeping heatup during charging due to a failed cooling loop.

Depending on your sizing and method, of cooling, I suspect you could see excursions to 60-70C during charging. So top end, 90C would be my choice. Which is still not 4th of July fireworks, according to NASA.

At the other end, to at least zero degrees C.

So, for my cars it would be

maybe orange -30-0C
yellow 0-15C,
green 15-xC
yellow x-60C with a "SC" mark at 45 or green from 40-60C
orange 60-90C

x is TBD - maybe someone has a rational basis for its bottom end value. Is yellow warranted during regular summer days in places like Thailand, where Bjorn Nyland found the cars to be running near peak efficiency in a place that normally is 35-40C in summer? I submit it's 40C. And 40-60 is SC*

*and super scoot current mode
 

Registered
Joined
54 Posts
What's "KM/T" supposed to be? Speed, in km/h? I can't tell if it's a typo (a good reason for sending artwork proofs) or something deliberate that just isn't apparent to me.

It's also strange to have yellow and red zones on a speedometer. That could indicate motor speed, but it would only make sense when using one specific transmission gear. Is marking zones on a speedometer a local thing there?

I live in Denmark where hour is time so it is called km/t.
The yellow and red are because it was made such original on datsun z.
You can also see my speedometer at the top of the thread there is a line from 100km / h and up

Watch Measuring instrument Gauge Clock Rim
 

Registered
Joined
54 Posts
Discussion Starter · #27 ·
According to tests from NASA, an 18650 cell doesn't light off until 120C on its case.


If you're trying to hit max rate charging, you're running the cell cases at 45C-50C for at least a dozen minutes. Half scale would not work, as you'd get zero visibility to a creeping heatup during charging due to a failed cooling loop.

Depending on your sizing and method, of cooling, I suspect you could see excursions to 60-70C during charging. So top end, 90C would be my choice. Which is still not 4th of July fireworks, according to NASA.

At the other end, to at least zero degrees C.

So, for my cars it would be

maybe orange -30-0C
yellow 0-15C,
green 15-xC
yellow x-60C with a "SC" mark at 45 or green from 40-60C
orange 60-90C

x is TBD - maybe someone has a rational basis for its bottom end value. Is yellow warranted during regular summer days in places like Thailand, where Bjorn Nyland found the cars to be running near peak efficiency in a place that normally is 35-40C in summer? I submit it's 40C. And 40-60 is SC*

*and super scoot current mode
battery temp scales to keep it slightly similar to battery SOC
 

Registered
Joined
3,538 Posts
I live in Denmark where hour is time so it is called km/t.
The yellow and red are because it was made such original on datsun z.
You can also see my speedometer at the top of the thread there is a line from 100km / h and up

View attachment 127827
One of the Scandanavian countries did traffic fines as a percentage of annual income, so is the red more than a year, then?
 

Registered
Joined
3,538 Posts
I make a canbus conversion from theNissan leaf canbus an send it to the gauges.
Do you have a comprehensive list of the gauge CAN messaging as well as Leaf CAN messages you could either link or post here, so when people want to hook up their gauge faces they can cobble up scale converters etc?

A lot of Leaf conversions in this forum (too puny for me)...it's the Warp9 of the 2020's
 

Registered
Joined
54 Posts
Discussion Starter · #31 ·
yes we have some harsh fine penalties. max speed on highway is 130km / h. if you go higer Them 200km / h they take the car from you and sell it on action then the money goes to the state

I will get back with the canbus project wen I鈥檓 ready with the gauges
 

Registered
Joined
8,091 Posts
I live in Denmark where hour is time so it is called km/t.
In the International System of Units the symbol for kilometre is "km", not "KM", regardless of language. The symbol for "hour" is "h", regardless of the word commonly used in the local language for hour (which I now know is "time" in Danish, spelled like the English word but meaning a specific unit :).... and pronounced "teem"). Using "T" makes sense to you and it's your car, but using non-standard symbols for standard units is not good practice in general... and even if you prefer the "T", I think using the lowercase "km" would be better, to keep at least the "kilometre" part using the correct symbol.

By the way, "T" is a valid symbol for a unit... the tesla, the unit of magnetic flux density. So "km/T" would be "kilometres per tesla". :D Ironically appropriate for an EV, but still physically nonsense. The lower-case letter "t" is not a unit symbol, so I suppose that "km/t" for "kilometer i timen" wouldn't be so bad.

The yellow and red are because it was made such original on datsun z.
You can also see my speedometer at the top of the thread there is a line from 100km / h and up
View attachment 127827
Okay, I get wanting the authentic marking feature. It makes no functional sense so it would annoy me, but I suppose it's harmless... and of course it's your car!
 

Registered
Joined
8,091 Posts
Although I participated in this thread, I didn't notice where it was in the forum... it is in what is supposed to be a wiki, rather than the discussion forums. Perhaps a moderator (I guess that's you, Matt ;)) could move the entire thread to where it belongs, in EV Conversions and Builds > Technical Discussion?
 

Registered
Joined
8,091 Posts
Just curious, niklaskinn... why did you choose this style for the dual gauge, instead of the "alternative sweep option" (shafts on the outside, needles extending inward) which gives a longer needle and longer (more readable) scale for the same sweep angle in the same face size?
 
21 - 36 of 36 Posts
Top