# CALB cell quirk



## twright (Aug 20, 2013)

Is this a brand new cell? Sometimes after they get a few cycles on them, they behave differently.


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## GerhardRP (Nov 17, 2009)

zapyourrideguy said:


> I have one cell that when charging never goes above 3.34 volts. the orion then balances the rest of the pack down to that point. I have had this cell out of the car and charged it on a regulated power supply and same thing it won't go above that voltage. It also when sitting by itself disconnected from everything self discharged over 2 weeks like a 3rd of a volt more than I have ever seen. In fact I have never seen any detectable discharge.
> 
> Has anybody seen this behaviour? According to the BMS resistance is normal .5 or so and it is not the lowest cell while driving. Also the Orion does not report it as a bad or weak cell.
> These are 180 ah grey cells


Sorry folks, this thread was completely hijacked and was getting unpleasant. I have deleted all posts not related to the OP question.
Gerhard


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## onegreenev (May 18, 2012)

I have two cells with slow shorts. The limit of 3.4 volts is most likely related to the internal short or shorts. My current cell is now down to just under 2 volts. I will charge to see if it settles at a specific voltage. I only charged to 3.6 volts anyway. I won't be using the cell for anything except experimenting on the damaged cell. So just pull the cell and replace it. Not all cells will be perfect.


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## racunniff (Jan 14, 2009)

I purchased 110 CALB blue 100Ah cells in 2012. They sat idle (in their crates, not attached to anything) for a year, were individually charged to 3.5 volts per cell and then put back in their crates for 9 more months. When I finally got around to installing, one of them would not hold a charge (dropped to zero volts over time). And a second one failed about a week after the pack was placed into operation - it went into reversal while I was driving (the BMS did its job - it was buzzing at me - but I had to keep going to find a safe place to stop). I have not had any more cell failures in the months since then.

I have not disassembled them to see why they failed.

I deliberately over-bought the cells to provide spares - the pack only uses 96 cells. I'm repeating this strategy with my next CALB LiFePO4 build (well, except for the "leave the cells lying around for years" part).


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## onegreenev (May 18, 2012)

Not likely you will SEE where the damage within the cell. It can be on a micro level and could be hidden well inside the cell. 

Pete


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## JRP3 (Mar 7, 2008)

racunniff said:


> were individually charged to 3.5 volts per cell and then put back in their crates for 9 more months.


That's the opposite of how you should store lithium cells. You really want them at 50% SOC or less for long term storage.


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## Moltenmetal (Mar 20, 2014)

That's puzzling: I thought that letting the cells go LOW was what killed them! If you leave them at <50% SOC and they self-discharge over time, won't that damage the affected cells? And what about keeping them fully or nearly fully charged is bad for them during storage?


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## racunniff (Jan 14, 2009)

JRP3 said:


> That's the opposite of how you should store lithium cells. You really want them at 50% SOC or less for long term storage.


It was not intentional, life gets in the way of the hobby at times...


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## dougingraham (Jul 26, 2011)

Moltenmetal said:


> That's puzzling: I thought that letting the cells go LOW was what killed them! If you leave them at <50% SOC and they self-discharge over time, won't that damage the affected cells? And what about keeping them fully or nearly fully charged is bad for them during storage?


Anywhere in the middle is good for long term storage. Around 3.3 volts resting is how they are shipped.

Good LiFe cells don't self discharge. If they self discharge then they were not good cells. If you experience what you think is self discharge the first thing to ask is was there anything connected to the cells. By this I mean a cell with nothing connected to the terminals. Any kind of parasitic load is not self discharge. BMS's are often parasitic loads. A bleeder resistor in the charger or motor controller or DC-DC converter on the filter caps would be a parasitic load.

I ran a six month test with three 100AH cells. I cycled them several times at 30 amps to get a baseline on capacity. I left one fully charged. I discharged one by taking 50AH out of it. The third I discharged to 2.5 volts. I put them in a closet for six months and checked the voltages. They were all within a few ten thousandths of a volt from the resting voltage six months before. (about 3.4 volts, 3.3 volts and 2.7 volts.) The capacity of the fully charged battery was unchanged. The capacity of the half charged cell was unchanged. The capacity of the cell that was left empty was reduced by about 0.5% if I remember correctly. Over a six month period there appears to be no issue with leaving fully charged or at a 50% SOC. But don't leave them fully discharged for extended periods.

I don't know at what point on the low end you can leave them stored but probably a resting voltage of 3.1 or above volts would be ok.

This was not an exhaustive test by any means. I would consider it more anecdotal evidence than anything else.


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## GerhardRP (Nov 17, 2009)

dougingraham said:


> <snip>
> I ran a six month test with three 100AH cells. I cycled them several times at 30 amps to get a baseline on capacity. <snip>


Did the capacity seem to change with the successive cycles?


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## dougingraham (Jul 26, 2011)

GerhardRP said:


> Did the capacity seem to change with the successive cycles?


Not really. My iCharger 3010b seems to have a resolution of somewhere between 150 and 300 mah when cycling a 100AH cell. I also have a CBAIII and it wanders around about that much. Temperature does matter and a few degrees temp change will change the capacity reading more than that over the three plus hours it takes to cycle a cell.

If there was a change over the few cycles I did in quick succession it was lost in the noise. But the capacity loss in the cell stored empty was pretty clear. I kind of wished I had plotted the discharge curves to see if there were other differences. And that is why I consider this anecdotal rather than hard data.


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## zapyourrideguy (Oct 25, 2012)

I got word that CALB is sending another replacement cell. They replaced 3 for excessive IR reported by Orion BMS. This cell is exhibiting self-discharge when out of the car and won't charge above 3.38 volts. 

I am happy with these batteries: Calb CA series 180's. and with customer service and replacements thus far. I am hoping that this pack is settled down. and there won't be any more replacements required.


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## zapyourrideguy (Oct 25, 2012)

Keegan at CALB replaced the cell under warranty the other 3 cells were replaced due to out of spec resistance. I am very happy with the customer service from CALB. We will see if I get any more bad cells 
-Mike


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## JRP3 (Mar 7, 2008)

Glad to hear it.


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## zapyourrideguy (Oct 25, 2012)

Update I still have a cell that will not charge above 3.4 volts in or out of the car.
It becomes the highest voltage cell in the pack through out the discharge cycle. I believe it is one of the replacement cells. I tried to get it replaced again but CALB did not approve it for replacement. So it appears the capacity is there just won't charge above that 3.4v
weird


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## riba2233 (Apr 29, 2015)

It happens with lifepo4 cells.. Got to love it


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## pdove (Jan 9, 2012)

LiFePO4 cells aren't supposed to charge above 3.38 volts. 
Sounds like nothing is wrong with that cell.


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## onegreenev (May 18, 2012)

Are you referring to the final resting voltage when you say they won't charge above 3.4 volts. No cell should be above 3.4 volts at rest after a full charge. No cell should ever go above 3.8 during the charge phase. I use 3.55 as my nominal terminal voltage but some cells are above that when the charge is finished but the resting voltage is never above 3.4. Ever.


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## zapyourrideguy (Oct 25, 2012)

No this is during charge in series or pulled from the car and put on a regulated power supply it does not go over 3.4 volts during charge.
I have 45 cells monitored by an Orion BMS and after charge to 3.6 before any load the normal cells will have a higher resting voltage and this odd cell will be at 3.33 as soon as a load is applied all the cells have a resting voltage to within .01 volt of each other including this odd cell. As I mentioned before this odd cell then becomes the high cell in the pack voltage wise.


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## pdove (Jan 9, 2012)

I find what you write very difficult to understand. Do you have a spreadsheet of the data to share?
I'm


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## zapyourrideguy (Oct 25, 2012)

I will try to post data from Orion BMS 
I am not very technical compared to you folks so it may take awhile.
Any tips as to what form would be appreciated. I know the Orion software can output several different forms of data csv?
Thanks for your response


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## twright (Aug 20, 2013)

.csv will be fine. With that form you can use Excel to do anything you want with it.


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