I want my 281!

[garygid]

Why is "SOC" low sometimes, and higher at other times, on the same car?

1. Most likely Cell-Balance (or lack thereof) is a major factor, but we do not know how to read the Cell Voltages that might HELP indicate the imbalance.

2. Temperature does seem to have an effect, and I believe others have reported that the Service Manual says that temperature can affect how [the end of] charging is done. If temperatures are higher, the "soc" (or gid) readings MIGHT be less.

3. Depth of Discharge: PERHAPS the Battery Management gains additional information about the cell-pairs when the battery is closer to empty. Only a "reasonable" conjecture at this point.

 

[TickTock]

I have kept track of readings after charging for the past month. Most of my charges have been to 80%.

For "100%"- highest reading 280 gids (gotten today, my highest ever); lowest was 263.
For "80%"- highest reading 231; lowest 217

Is the variability seeming random? Or are you observing an upward trend?

 

[LEAFfan]

For "100%"- highest reading 280 gids (gotten today, my highest ever); lowest was 263.
For "80%"- highest reading 231; lowest 217

When you say '100%' and '80%' charging, what SOC% does your gauge read? I can't compare raw numbers, just SOC%. My LEAF ScanGauge reads 94% for 100% charging and 77% for 80% charging.

 

[91040]

I have kept track of readings after charging for the past month. Most of my charges have been to 80%.
For "100%"- highest reading 280 gids (gotten today, my highest ever); lowest was 263.
For "80%"- highest reading 231; lowest 217

Wow, that's a lot of variability for one Leaf. Any hints on factors that might have an effect (e.g., temperature)?

Is the variability seeming random? Or are you observing an upward trend?

When you say '100%' and '80%' charging, what SOC% does your gauge read? I can't compare raw numbers, just SOC%. My LEAF ScanGauge reads 94% for 100% charging and 77% for 80% charging.

I started logging the readings when I noticed they were very low. This coincided with a heat wave in LA. I leave it up to those with a strong engineering background to interpret these results.

There has been a general upward trend since I started logging these values. The improvement has not been smooth though.

When I refer to 100% and 80% charge, that is what the car was set to do. The gauge in the car showed 12 bars or 10 bars respectively. These "gids" can be converted to percentage by dividing them by 281. So:
For "100%"- highest reading 99.6% (gotten today, my highest ever); lowest was 93.5%.
For "80%"- highest reading 82.2%; lowest 77.2%

Pack voltage has been very consistent around 393v for 100% charge; 388v for 80% charge.

 

[garygid]

Our "gids" (a value from a message on the EV-Bus) seems
to have an upper limit (highest value yet observed and reported) of 281.

So, ( gids * 100 ) / 281 = gids / 2.81 => our "Percent SOC".

Likewise, %SOC * 2.81 => "gids".

I talked to Ron at ScanGuage, and he needs to verify with his
programmer what divisor they are using for %SOC in their "ScanLeaf".

I am using 281 in our SOC-Meter.

 

[LEAFfan]

I talked to Ron at ScanGuage, and he needs to verify with his
programmer what divisor they are using for %SOC in their "ScanLeaf".
I am using 281 in our SOC-Meter.

When I asked Joey to ask Jamie, Jamie said they were using '281'.

 

[TomT]

I was told the same thing. Odd that the numbers from the two gauges appear to be different... Does anyone have both so that they can be directly compared?

When I asked Joey to ask Jamie, Jamie said they were using '281'.

 

[garygid]

Who with an SOC-Meter in AZ can link up with LEAFfan
to compare "soc%" readings?

 

[LEAFfan]

After a cell balancing to 100% (94% SOC), I did an 80% and it increased my percentage to 77.2. Before it always was 76.8. Do the cells get balanced after only one 100% charge? I left it plugged in after the 100% charge for almost two hours.

 

[DaveEV]

After a cell balancing to 100% (94% SOC), I did an 80% and it increased my percentage to 77.2. Before it always was 76.8. Do the cells get balanced after only one 100% charge? I left it plugged in after the 100% charge for almost two hours.

They should get balanced, but no one knows exactly how much balancing will occur. Data from others has shown that balancing can go on for at least 4 hours after the first stop to 100%. Gotta get one of these low Gid cars on a house with a TED and charge to 100% and let sit for 24 hours or more to see what happens.

 

[mwalsh]

I've had two days of lower readings now - 95.x % on Tuesday morning and 92.5 % as of this morning. I should be due either another low reading (maybe 91.x %) or a bump to a high reading with tonight's charge.

 

[TonyWilliams]

I've had two days of lower readings now - 95.x % on Tuesday morning and 92.5 % as of this morning. I should be due either another low reading (maybe 91.x %) or a bump to a high reading with tonight's charge.

I wonder if this cell balancing is strictly a voltage thing, or a time thing, or some other combo?

 

[garygid]

Cell Balancing (as I suspect it works).

1. The LEAF measures and monitors all 96 cell-pair voltages.
2. It watches the highest voltage to stop charging.
3. It watches the lowest voltage to "stop moving".

4. At some time, probably after charging of some kind is finished, the LEAF identifies any "HIGH" cell-pairs (pairs, if any, that are too much higher than the "average" cell).
5. The HIGH cell-pairs are discharged a bit, probably at a rate noticably less than 1 amp, for about 45 minutes.
6. Then, IF the LEAF is still plugged in, it may charge (at a low rate) all the cell-pairs for a short time, probably for only 5 to 10 minutes.
7. The cycle may repeat, if needed. We believe two cycles have been observed.

If the cells are well matched, and only slightly out of balance, this process should work well.

One, or a few HIGH cell-pairs can gradually be corrected, but it might take many cycles.

One (or a couple) low cell-pairs ... could be handled, but ... only by discharging MOST of the cell-pairs.

We do not know WHEN the process (a cycle) happens, or what causes/allows it to happen.

 

[garygid]

Symptoms of a High Cell-pair:
1. Charging stops with the Pack Voltage a bit lower than normal (many cells are low).
2.

Symptoms of a Low Cell-Pair:
1. Pack Voltage at the end of charging will be essentially "normal" (most cells are at "normal" voltage).
2.

Symptoms of a Low-Capacity Cell-pair:
1. Range will be less than "normal".
2.

 

[ebill3]

I charge only L1 and normally 80%. I consistently get 231 gids, 388.0 or 388.5 volts.
Several days ago I charged to 100% and read 276 gids, 392.5 volts.

Last evening, while at 231 gids, I punched the over ride for a 100% charge. The charge stopped about 11 PM and the car remained plugged in. At about 10 AM, it was 278 gids, 393.5 volts. Punched the override and 30 minutes later, it was 275 gids. A bit later, hit the over ride again, and it went to 273 gids.

What the heck?

Bill

 

[91040]

My guess is that the battery management system will not allow further charging. The cooling system for the inverter/charger runs until the BMS turns off the "charge" and that uses electrons.

 

[Bassman]

Quote: "I've had two days of lower readings now - 95.x % on Tuesday morning and 92.5 % as of this morning. I should be due either another low reading (maybe 91.x %) or a bump to a high reading with tonight's charge."


This might explain why I ran into turtle mode 3 miles from my house last Thursday and had to have Nissan tow me home. It's the first time I didn't make it home in over 5 months of driving. I had taken a detour route which added 13 miles to my normal commute, a route I had done before with mileage to spare. This time it was a different story eventhough my car indicated a full charge when I left work. I don't have the SOC meter, it may have saved me. The next Monday, I left work with a full charge and arrived home at very low battery (--- miles blinking) and this was using my normal 63 mile route where normally I get home with 8 to 11 miles and one bar. The next day I get home with 13 miles remaining and two bars showing. It must have been due to cell balancing.

 

[mwalsh]

I don't normally charge to 80%, but I did last night, just to see what would happen. I ended up at 77.9% / 219 gids.

 

[LEAFfan]

I don't normally charge to 80%, but I did last night, just to see what would happen. I ended up at 77.9% / 219 gids.

I charged last night to 80 percent and got my highest yet, 77.2 percent . but by morning it was back to 76.8 percent.

sent with speech to text from my android phone

 

[Boomer23]

Mine's been 280 to 281 pretty reliably for a couple of weeks. This morning it was 271. But it's been crazy hot here, so I'm thinking temperature is rearing it's ugly head. Update to come tomorrow, since it's still hot here.