Questions about low-battery range, turtle behavior and LeafSpy readings

I'm down to an estimated 1.5 miles to LBW, 11.2 miles to VLBW at 5.1 miles/kWh, which is what I've been averaging, (29.9% SOC, 18.9% GIDs, 53 GIDs) and want to run it pretty low today to determine my overall range, but don't want to be one block from home and unable to make it up the alley!

First question: LS says 15.0 miles to 5%. Five percent what? SOC? GIDs? Something else?

Is 5% the start of Turtle mode? If not, why "5%" as a prediction setting?

If I want to run it very low, I can do laps in my neighborhood, which has a significant grade down (like, 7 or 8%) to the south of my house and a gentle grade (1 or 2%) up to the north, so if I'm getting very low, I can stay on the north side and have a slight downhill all the way home, except a hundred yards up the alley to my house that climbs about 5 feet. If it turtles, is it a safe bet to go half a mile or so down hill then up the alley?

As a side note, try not to keep it very long at a very low battery level. This isn't great on the battery.

If the battery temp is not up in the yellow range, I'll put it on to charge immediately after I get home. If it's warm, I'll let it sit in the shade for a few hours first, or set the charging timer to start around 10 PM.

My experience is with a 2011 Leaf.
There is approximately 3kWhs of useable energy at LBW. If you have the LeafSpy set for 5m/kWh, the 15 mile projection to the point of shutdown makes sense. My car shuts down at ~6 Gids / 0.5kWh.

Remaining range after turtle depends on how well balanced the individual cells are. One outlying low cell will cause an earlier shutdown. Be very gentle in applying power after turtle if you need to go a distance.

BuckMkII said:

I'm down to an estimated 1.5 miles to LBW, 11.2 miles to VLBW at 5.1 miles/kWh, which is what I've been averaging, (29.9% SOC, 18.9% GIDs, 53 GIDs) and want to run it pretty low today to determine my overall range, but don't want to be one block from home and unable to make it up the alley!

First question: LS says 15.0 miles to 5%. Five percent what? SOC? GIDs? Something else?

Is 5% the start of Turtle mode? If not, why "5%" as a prediction setting?

If I want to run it very low, I can do laps in my neighborhood, which has a significant grade down (like, 7 or 8%) to the south of my house and a gentle grade (1 or 2%) up to the north, so if I'm getting very low, I can stay on the north side and have a slight downhill all the way home, except a hundred yards up the alley to my house that climbs about 5 feet. If it turtles, is it a safe bet to go half a mile or so down hill then up the alley?

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BuckMkII said:

If the battery temp is not up in the yellow range, I'll put it on to charge immediately after I get home. If it's warm, I'll let it sit in the shade for a few hours first, or set the charging timer to start around 10 PM.

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If I get below 20% in hot weather, I'll charge it just above 20% (on L-1) and then unplug it and let it cool before finishing the charge in the morning.

Although it was sunnier then I expected today, it was still good battery charging weather. After my last 10 mile drive this evening, the mean battery temp sensor reading was 65°. I felt it was safe to start an L1 charge at that point. :lol:

I only got down to 19 GIDs remaining. LS said I could drive another 2 miles to 5% (of which I still don't know the significance), but I feared my spousal critter would become impatient if I spent another 10 minutes orbiting the neighborhood before lighting the grill, so I cut off the process at that point.

BuckMkII said:

Although it was sunnier then I expected today, it was still good battery charging weather. After my last 10 mile drive this evening, the mean battery temp sensor reading was 65°. I felt it was safe to start an L1 charge at that point. :lol:

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My battery pack hasn't seen 65° for at least 2 months! I'm lucky if I can plug it in @85° these days.

You're in Seattle, you have no need to worry about battery temperature. It is best to start charging (either L1 or L2) soon after deep discharge regardless of temperature. I hit 11 temperature bars yesterday (probably the first time ever for the 2015) during the second QC of the day. The QC stopped at less than 80% SOC and driving power was limited to about 45 kW (full regeneration was available). I drove a few miles and then parked while eating dinner. The battery cooled enough to allow full power acceleration during the rest of my errands.

The lithium battery controller (LBC) opens the main contactor when the lowest cell pair voltage reaches the minimum level. The LBC requests turtle mode when it determines that there is very little energy available to reduce maximum power and reduce the risk of hitting the shutdown threshold. Since the LBC is looking at the lowest cell pair voltage, cell balance (or unbalance) can greatly affect the point that turtle mode happens and especially the distance between turtle and shutdown. My 2011 might go 1/4 mile in turtle mode with VERY gentle driving, but the 2015 will normally go a little further. My battery pack is normally very well balanced because I always charge with L2 at home to 100% and frequently discharge to LBW or VLBW (low battery or very low battery warning). It was down to 7 Gids by the time I reached the QC station yesterday and the LBC had not engaged turtle mode. Turtle mode normally happens at 5 Gids (but could happen at 6) and shutdown happens at 4 Gids with my well-balanced battery in the 2015 when using climate control while parked to in the driveway. I know these thresholds because I have been discharging the battery to shutdown once a month and recording L2 charging power from the wall to track battery capacity loss.

Edited to note turtle mode at 5 Gids instead of 6 after checking my records.

I was mostly being tongue-in-cheek about the battery temp, although I did see yellow bars on the graph in LS one day last week. I didn't take them too seriously.

Good idea using the AC to run the pack down in the safety of your driveway! I wonder how many years it would have taken me to come up with that idea on my own?

Stanton said:

BuckMkII said:

Although it was sunnier then I expected today, it was still good battery charging weather. After my last 10 mile drive this evening, the mean battery temp sensor reading was 65°. I felt it was safe to start an L1 charge at that point. :lol:

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My battery pack hasn't seen 65° for at least 2 months! I'm lucky if I can plug it in @85° these days.

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Mine hit 113 degrees the other day.