More range w/ 100% charged unbalanced vs. balanced battery?

[nosuchthing]

I've noticed this for the first time based on the GOM numbers upon takeoff. It seems that I have somewhat more range when I stop charging with 100% 3 lights on (solid - not blinking) than 100% charged w/ 3 lights off and the battery balanced.

Is it possible, and if so is there an explanation for that?

 

[Stoaty]

GOM = Guess-o-meter

That pretty much says it all in my opinion.

 

[Luft]

I've noticed this for the first time based on the GOM numbers upon takeoff. It seems that I have somewhat more range when I stop charging with 100% 3 lights on (solid - not blinking) than 100% charged w/ 3 lights off and the battery balanced.

Is it possible, and if so is there an explanation for that?

The GOM numbers are of little value. The number it will give you is based on the charge and how you were driving a short time previously. Any conclusion of that kind based on the GOM would probably be erroneous.

 

[nosuchthing]

I do know what GOM means, and have 2-year 36,000-mile experience with my Leaf. So, let us not get confused here. This is an empirical observation I have made today and it struck me as unusual and unexpected.

 

[cwerdna]

I do know what GOM means, and have 2-year 36,000-mile experience with my Leaf.

http://www.mynissanleaf.com/wiki/index.php?title=Glossary" onclick="window.open(this.href);return false;
http://www.mynissanleaf.com/viewtopic.php?p=271853#p271853" onclick="window.open(this.href);return false;

 

[Stoaty]

I do know what GOM means, and have 2-year 36,000-mile experience with my Leaf. So, let us not get confused here. This is an empirical observation I have made today and it struck me as unusual and unexpected.

Yes, but an empirical observation about a completely unreliable "gauge" has little meaning, wouldn't you think? If you want to know the effect of a balanced vs. unbalanced battery, you need a Gid meter. Also note that even with a Gid meter you will see significant variability between 100% charges in the number of Gids obtained depending on battery pack temperature, phase of the moon, etc.

 

[nosuchthing]

Also note that even with a Gid meter you will see significant variability between 100% charges in the number of Gids obtained depending on battery pack temperature, phase of the moon, etc.

That's exactly what I'm after: you say there is a variablility between charges... Is it then possible that balancing is somehow involved in that variability by robbing Peter to pay Paul thus possibly causing some of the leveled-off power to become inaccessible -- or something to that effect. The end result being that you lose a fraction of usable kW, thus a few miles of range.

I'm just wondering.

 

[surfingslovak]

Also note that even with a Gid meter you will see significant variability between 100% charges in the number of Gids obtained depending on battery pack temperature, phase of the moon, etc.

That's exactly what I'm after: you say there is a variablility between charges... Is it then possible that balancing is somehow involved in that variability by robbing Peter to pay Paul thus possibly causing some of the leveled-off power to become inaccessible -- or something to that effect. The end result being that you lose a fraction of usable kW, thus a few miles of range.

I'm just wondering.

I think that part is plausible. My understanding is that stronger cells are drained a bit during the balancing process. The pack it then recharged, giving weaker cells a chance to catch up. This is just a guess, but depending on where your pack was during this process, some capacity might have been lost. Still, and like others said, the GOM on 2011 and 2012 LEAFs is hardly a reliable and consistent indication of usable capacity. I'm sure you are well aware, just like you stated above. Any observation involving the GOM is to be taken with a large grain of salt.

 

[nosuchthing]

An interesting experiment would be to GID meter it when the last blue stops blinking and all 3 are blue, and then again when all three go off after balancing.

Then we would know more.

 

[surfingslovak]

An interesting experiment would be to GID meter it when the last blue stops blinking and all 3 are blue, and then again when all three go off after balancing.

Then we would know more.

Could you get an ELM327 clone and hook it up to an Android phone? There is a whole thread on this topic, but it has a very non-descriptive title: Using clone ELM327 Bluetooth OBDII adapter with Leaf

 

[garygid]

When charging is completed, the 3 lights go on steady.

After a time delay, a fixed time of about 10 minutes or so,
I think, the lights turn off. But I could be wrong.

The balancing of the cells goes on almost all the time,
with the BMS turning on the Shunts on each high cell,
whenever it chooses to do so.

With the ELM327-type device and Turbo3's Android app,
I see many shunts On almost all the time in my 2011 LEAF.
Further, I think that we have just figured out how to assign
the Shunt-On bits to the correct cell-pairs.

 

[DaveEV]

My understanding is that stronger cells are drained a bit during the balancing process. The pack it then recharged, giving weaker cells a chance to catch up.

Hard to know for sure if it's the strong cells or the weak cells are the ones that tend to have higher voltage at the top of the charge. All we know for sure is that the pack is top balanced which means that the highest voltage cells are bled off to match the voltage of other cells.

If the weak cells are being bled down, then yeah, you could lose range. If the strong cells are being bled down, then you might not lose any range.

 

[surfingslovak]

Hard to know for sure if it's the strong cells or the weak cells are the ones that tend to have higher voltage at the top of the charge. All we know for sure is that the pack is top balanced which means that the highest voltage cells are bled off to match the voltage of other cells.

If the weak cells are being bled down, then yeah, you could lose range. If the strong cells are being bled down, then you might not lose any range.

That's a good point, I could easily have it wrong. And a hat-tip to Gary also.

 

[davewill]

... My understanding is that stronger cells are drained a bit during the balancing process. The pack it then recharged, giving weaker cells a chance to catch up. ...

The recharge part doesn't necessarily happen. I think it would depend on how far down the whole pack ends up after the balancing occurs. It's possible you wouldn't see any improvement until after the next charge.

 

[mkjayakumar]

I have seen the GID numbers, before and after the blue lights .. no change at all.