Leaf Spy

[Jamesjeff]

Hello, Can someone explain all about Gigs please

 

[DougWantsALeaf]

Did you mean GiDs?

 

[Jamesjeff]

Did you mean GiDs?

Silly me, yes I did mean GiDs, mine says 62.3% with 76.6% SOC with another number 175?

 

[Jeffstumpf]

From the Leaf Spy Pro app, built-in help screen….

GIDs ( a custom unit of energy) This field indicates the remaining energy in battery in terms of Gids. Gids is the name given to a value found on the Leaf CAN ( Controller Area Network ) bus that tracked closely with the amount of energy remaining in the Leaf Battery. It was first discovered by Gary Giddings. Later it was determined that Nissan uses this field to indicate the amount of usable energy in the battery by multiplying it by 77.5. On a new 2011 Leafs the maximum Gids is typically 281 or (281 x 77.5) 21.78 kWh of usable energy from the 24 kWh battery.

The default Wh/Gids is 77.5. The calculated kWh (left in the battery pack, is based on this value ant it ) gives the best indication of available energy in the battery.

 

[nlspace]

What's the PID for Gids?

To have a max value of 281 means it is sent as 2 bytes of data in the CAN buss PID, e.g, 281 decimal is 0x01 0x19 in hexadecimal as would be read in the CAN data.

It seems like the best indication of available energy would be related to the current (draw or charge) as measured by the current sensor. Doing some calculatus, a time integration of the current sensor data would give an exact energy status, aka Coulomb counting.

A capacity measurement where 1 bit represents 77.5 Whr is a rather crude sense measurement seems to me.

In days of old, when knights were bold, and CAN hacking wasn't invented--the meaning of PIDs was subject to lots of guessing and inference.

Thanks to Gary for his early work and attempt to make a Gidmeter, but it's time to move on, simplify and use engineering units that are well understood.

 

[woeful]

There's no PID for GIDs, as far as I know. There is a 9-bit field in CAN message number 0x5B3, transmitted many times per second from the VCM (vehicle control module) as a raw data feed into the instrument cluster. That's not part of the PID system; it's lower-level data, part of the continuous chatter of every (well, most of 'em) vehicle module over the CAN bus.

You may think this a crude measurement, but it is the best available data as fed out of the car's battery control electronics for use by any of the other vehicle components which may need it. Unless you seriously propose replacing the battery (BMS) firmware, there's nothing better.

If you want to replace this with engineering units that are well understood, you need a time machine to go back and explain to the Nissan software engineers of the noughties that you'd like them to use some other unit in CAN bus message code 5B3 of the LEAF. Gary did a great job to identify the right part of the data stream.