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Batrium LongMon's accuracy
#11
Again - very interesting.  I now have 84 longmons...   and while I haven't go all out balancing things (0.04v diff is OK with me), I too have noticed weirdness.   

I have a couple of packs that just seem to go a bit higher and a bit lower each day - no matter what I do.    I've done individual pack charging to 'nudge it' (for example) up with others but doesn't seem to make things better.   I hadn't considered the longmons may be 'just a touch weird' themselves - but after 2 yrs of this I've generally come to accept that 0.03v - 0.06v fluctuation each day between 4.1v high and 3.5v low    

If you look at pack #26 - you can see one of my weird ones - it just sticks out, but if I pull it down it will just be low in the other direction.
NOTE: I just added a new 14s battery yesterday (#1 thru #14 below), so I'm using Auto-Level to bring it all within 0.04v difference on lower end.


I do try to keep my OCD in check as I have no plans to go above 4.0v or lower than 3.5v for long life - so a 0.04v-0.06v dif makes no difference at all and its *stable* over many months of charge/discharge...  so the packs must be OK.

But I do find this topic very interesting...
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#12
Your balancing did work before as well. Its just a graphicaly intepretation. What you saw when 1 pack balanced more will happen in time when it drifts out of the callibrated scope.

OCD on the graphs is one thing and how it works in real life is something else. No matter if its off 0.05 all cells will have the differences and especially under 4.2V this is normal.

One or many packs will always be off unless you constantly rebuild them or have new cells Wink

With that said if you let the BMS do its job you dont have to bother. I have my system running for many years and the only thing i have done so far is swapped our a couple of longmons that stopped working. The battery bank itself is running.
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#13
Never to question the master of the Batrium as I have watched every video you have put out on it.

BUT if I have my charge controllers set at 4.05 and my bypass set at 4.07 on auto with a 0.03 difference and 1 of my longmons shows 4.10 something is wrong especially if my fluke shows 4.04V.
This will cause the Batrium to go into bypass when it is not required and venting 1 longmon. That is what I experienced graphical representation or not.
After moving the longmon things settled down, another experience in real life.
After a dreary day yesterday my packs where down to 3.6V very even across the board. Today is a very nice day and I am charging very well with a difference of 0.02.   By past experience as I approach 4.05V per pack there will be a very pretty dance of bypass flickers as the "low" cells catch up never a prolonged bypass by just 1 longmon.
I understand you have been running this system for years compared to me but again I have built my packs with very stringent criteria and hoped to accomplish a very even balanced 14s pack that requires a minimal of intervention. I consider Batrium a battery monitoring system and if needed a little tweaking here and there to maintain an even charge across all packs. I obviously don't consider the Batrium a fixer for poorly designed packs.
As of 11:38 Am today. Once I hit 4.05 I will try to post another screen shot of the bypass dance.


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#14
Well as I reach peak saturation of the pack I see that today will not be a balancing day. Sorry Tongue 

101 SOC% and 3.17A charging. 0.01 difference in V between packs.
No balance necessary.


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#15
As i said in the beginning this will only happen the first day. Then they will be balanced based on the "wrong" value. So if you look at it that way its nothing special and all values we have are "wrong" values and will be balanced towards that. no matter what if that value is below 4.2V its not a problem

With that said the total voltage may be different so you may callibrate your charger and inverter towards the BMS but when thats done its fine.


So once again the difference you see is not a real world issue if you live with it and only look at 1 source.

Its like taking 1 red Car. that car will look red right? But if you place that Red car beside another Red car from another brand you will most likely say that one of them arent as red as the other... Big Grin So remove them again and you suddenly have red car.

Its all about how you look at something and a value is just a value presented by a set of parameters Wink Yes, one of my interesting areas are numbers and how you can turn them around.
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#16
Well being the pain in the backside as I am all in all I do agree with you. Smile
However the problem did not resolve itself after the first day nor the second nor the third. That is why I decided to switch the longmons and I was successful as the problem did resolve itself by doing just that.

As far as red is concerned as RGB its 255,0,0 or in HEX its FF0000. Now if you change it to 255,1,1 or FF0101 is it still red? Visually yes but digitally no it now has green and blue mixed in. It's all in the numbers Tongue

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#17
Yeah Smile


I have painted alot of cars in My days and what One person är is not the same as another hehe. Same with meters
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