Why GIDs instead of kWh?

If I'm understanding correctly, Gids = kWh * 12.5. IOW,

If that's true, what's the point? Why do we need another unit that means the same thing?

I'm not sure if that equation is correct, but that's beside the point. Gids are smaller units than KWH, allowing for finer and easier visualization of remaining power in the battery, with no mental on the fly fractionalization or decimalization needed.

PianoAl said:

If I'm understanding correctly, Gids = kWh * 12.5. IOW,

If that's true, what's the point? Why do we need another unit that means the same thing?

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I'd suspect they chose a unit that would make the best use of a certain number of bits used in the CAN message traffic. The customer was never meant to see these numbers. Though I've always thought they did the customer a disservice by not having an energy display with straight-up watt-hours. The original "12 Bar" display is ludicrous in every way but at least they did put in a percent meter after a couple of years.

Yes, I guess it was dumbed down for people who have trouble with numbers like 20.3.

The term "Gids" has nothing to do with Nissan, that's the name they were given here on this forum in honor of Gary Giddings, who developed the first aftermarket CANbus battery monitor for the LEAF, the gidmeter. I have no idea why Gary choose to use that value, but I'm sure you could ask him.

As stated by Nubo, the value was created by Nissan. GaryGid and Turbo found a data stream on the EV Can that corresponded to the available energy in the battery. Not knowing what Nissan called it, this forum coined the name. It seems to be about 80Wh into the battery and about 75Wh out.

GRA said:

The term "Gids" has nothing to do with Nissan, that's the name they were given here on this forum in honor of Gary Giddings, who developed the first aftermarket CANbus battery monitor for the LEAF, the gidmeter. I have no idea why Gary choose to use that value, but I'm sure you could ask him.

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AFAIK, it was found to be ~281 on a brand new battery at full charge. It went down as the battery discharged and went up as the battery charged. See http://www.mynissanleaf.com/viewtopic.php?t=5582.

And later, it was found that the value at full charge would be less as the battery degraded. People used this as a proxy for % SoC since the '11 and '12 Leaf didn't have the % SoC display.

91040 said:

As stated by Nubo, the value was created by Nissan. GaryGid and Turbo found a data stream on the EV Can that corresponded to the available energy in the battery. Not knowing what Nissan called it, this forum coined the name. It seems to be about 80Wh into the battery and about 75Wh out.

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Yep on all of this. I don't know there's an agreed upon value of that's 100% correct all the time as to how many Wh it corresponds to or what the range can be. So, to answer the OP, sure, you could use kWh, but you could have GIGO (Garbage In Garbage Out). All you have are gid values and to apply * 75 or * 80, well, it might actually be wrong.

Also, I hear the the gid values get squirrelly as you get really low (somewhere below VLBW).

Gids are defintely not linear. They don't seem to hold as much energy per unit at the very top of the range than the rest. They are fairly consistent at the very bottom with a balanced battery and the temperatures we get in Los Angeles.

91040 said:

Gids are defintely not linear. They don't seem to hold as much energy per unit at the very top of the range than the rest.

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Which is exactly why I'd say it's not a great idea to multiply 75, 80 or whatever by gid # and conclude the battery really has the result as the # of available kWh.

With LeafSpy, I am able to use the full capacity of the traction battery with confidence. This was especially necessary with the original battery as it degraded. I believe that LeafSpy calculates the remaining kWh based on Gids.

Another reason that people used it is that it is an absolute number of battery capacity, not a relative number of battery fullness like the SOC% on 2013 and later Leafs...

cwerdna said:

And later, it was found that the value at full charge would be less as the battery degraded. People used this as a proxy for % SoC since the '11 and '12 Leaf didn't have the % SoC display.

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