LeafSpy Pro questions/observations

[Jefe]

I've been using LSP now for a month, so I have learned my way around the app and have a good bit of data stored and I have a couple of questions.

1. The display of battery cells (screen 1) says that a red line indicates a bleeder load being applied to balance the cell. Have you ever seen it where all but 2 cells are red? Why would it bleed 98% of the cells to match just 2?

2. This is a little more involved. My question is how is SOH calculated? It seems to be closely related to the Hx value.

here's my scenario:

I have a 2013 SV with 16K miles on it (i only put 1500 of those on it). I didn't have LSP when I bought the car, but testing it after the fact revealed that I had a pretty good battery, showing a 99% SOH. It mostly bounced between 99% and 98%, but then over the winter break it dropped down to 96% for a charge cycle, then up to 97% for a few days. At the time, I was only charging to 80% since my daily driving decreased. Now I'm back to work and I'm charging to 100%, but yesterday my Hx went up to 100.56, and my SOH went to 100%.

Is this possible? Does anyone else have a 2013 with a 100% SOH?

 

[Jefe]

Also, my AHr has increased from 64.452 (98%) to now 65.779.

 

[Levenkay]

1. The display of battery cells (screen 1) says that a red line indicates a bleeder load being applied to balance the cell. Have you ever seen it where all but 2 cells are red? Why would it bleed 98% of the cells to match just 2?

Just a guess, but the "add an extra tiny drain to selected cells" mechanism for balancing only works in one direction. It can't "ADD a tiny bit of charge" to the few cells (in your example) that need it, even if that would be a much more efficient thing to do, energy-wise.

 

[dwl]

1. The display of battery cells (screen 1) says that a red line indicates a bleeder load being applied to balance the cell. Have you ever seen it where all but 2 cells are red? Why would it bleed 98% of the cells to match just 2?

I am new to this forum and picked up my Leaf yesterday. When I checked it at the dealer prior to purchase with LeafSpy Lite it had about 1/4 of the cells showing shunting (red) with 91% SOC. Cell balance and SOH was good so I bought the car. As the other post mentioned, bleeding is the current design rather that adding charge to low cells.

Mine now shows all except one pair red but I have been told that giving it a 100% charge with time to balance should make a difference. I'll update after a few more cycles and would be interested in other comments. There have been some other threads with the same question and the normal response seems to be not to worry about it but it does look a bit disturbing.

This is a great community and resource, almost too much information

 

[Jefe]

1. The display of battery cells (screen 1) says that a red line indicates a bleeder load being applied to balance the cell. Have you ever seen it where all but 2 cells are red? Why would it bleed 98% of the cells to match just 2?

I am new to this forum and picked up my Leaf yesterday. When I checked it at the dealer prior to purchase with LeafSpy Lite it had about 1/4 of the cells showing shunting (red) with 91% SOC. Cell balance and SOH was good so I bought the car. As the other post mentioned, bleeding is the current design rather that adding charge to low cells.

Mine now shows all except one pair red but I have been told that giving it a 100% charge with time to balance should make a difference. I'll update after a few more cycles and would be interested in other comments. There have been some other threads with the same question and the normal response seems to be not to worry about it but it does look a bit disturbing.

This is a great community and resource, almost too much information

I have definitely had it display both ways. Sometimes the red are just a few cells scattered, but it just struck me when I saw all but 2 cells being bled. I get that it can't charge those weaker cells because there is no reliable source of energy at that point, unless it in fact is bleeding the high cells to feed the weaker ones. The idea that it bleeds 98% of the cells and throws that energy away is unfortunate. But maybe it's not doing that. I'm not sure if it's known what a bleeder load means exactly. Maybe it just means that it is pulling all energy requests from those cells over the blue ones.

Anyway, it was more an interest. I'm not worried about it, just trying to better understand what I'm seeing.

I do still wonder about my recent improvements in SOH and AHr. What was your SOH, dwl?

 

[dwl]

I do still wonder about my recent improvements in SOH and AHr. What was your SOH, dwl

The cars I checked here were used imports from Japan only recently arrived so haven't been getting normal driving/charge cycles. I suspect they charge them to 100% in Japan and they sit like this for a couple of months so results can be misleading.

On the lot it had SOH 99%, SOC 91.4%, Hx 99.75% and 65.25AH. After use down to 30% yesterday I gave it 100% charge overnight and have just taken friends to airport which is 84km round trip (with some hills) and now down to 40% charge (SOC 46%) and showing SOH 98% and 64.49 AH with one pair blue and all others red but total pack difference only 16mV so not too worried at this stage. I suspect I have a slightly weak cell pair.

I think small changes in SOH or AH can be expected. In my case it is probably still working out actual capacity. It is worth logging the changes and your improvement might be a genuine gain but the trends over longer periods are the more accurate answers.

I believe the reason that "bleed many cells rather than charge one" is used is for simplicity. These are series strings of cells where each at 4V needs to be independently managed and this process isolated from high voltages. Deriving and applying voltage just for one cell pair would be a lot harder than switching in some resistive load. Hopefully the amount of energy wasted isn't high and should be a more reliable process.