BMS functionality question

Other Hardware Motors, Mechanics, Power and CNC
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Hello:

I have a small LiFePO4 battery consisting of (4) 12000 mAh (or 12 Ah) LiFePO4 cells connected in series.

I also have (2) BMS boards which I also purchased for protection, although I’m not completely convinced of their necessity, particularly with the relatively safe LiFePO4 chemistry.

I further purchased some LiFePO4 “active balancers” in the hope of saving a little extra energy when balancing.

It appears the the BMSs that I have also have a balancing function and uses the typical and more common resistive element to “bleed off” the excess energy from the stronger cells.

To the question: I am tempted to just use the balancing circuit and do away with the BMS, because I don’t want to use the BMS’s resistive balancing method along with the active balancer.

Should I pick a “better” BMS that does not have a balancing function (and then use it concurrently with the active balancer), or would it be okay to dispense with the BMS altogether and just use the active balancer?

Thanks for the constructive criticism!

Tentoes

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Please read and use this link: How to get the best out of this forum - Using Arduino / Project Guidance - Arduino Forum

Poetry doesn't work well here.

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I don’t see what is inappropriate about posting this here.

Also I don’t understand what is meant by “poetry doesn’t work well here”…??

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The place You posted in is good but not the information You provided.
"Poetry".... Words, words, words. That's not what the link above tells You to use.

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For the life of me I still have no idea of what you are talking about.

I believe that the question I posed is perfectly clear and concise and does not need schematics, pictures nor ANYTHING requiring elaboration.

Please defer answering to someone else who is a little less anal-retentive than you

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still not clear where is arduino here.

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Wow so I am going to cut my losses and move on to another venue……

In part I have myself to blame for coming back to this “bonfire of the egos” in the expectation of getting some useful guidance but you have proven once again that this forum still has the same pathologies as before….

Good bye and good riddance

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I don’t recall seeing anything in the section’s title that requires any and all posts to include the word Arduino in it.

Maybe my BMS will be powering a whole mol of Arduinos, in that case would you be satisfied?

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Bit touchy aye. If you want good help, then get over it.
This is the best forum ever, filled with old farts (70 here) with a wealth of experience.
But some will get grumpy when you don't adhere to the forum rules (posting hardware links and code). If you become a guru, you will see why.

Those two things are AFAIK the same thing.
A BMS has many active balancers, one for each cell.

They work by taking the charging current away from the cell (turning it into heat) when the cell reaches a certain voltage. So a BMS or cell balancer only works during charging.
That said, a better BMS could also have a pack deep discharge cutoff.

A LiFePo4 BMS is different from a LiPo BMS,
because a LiFePo4 needs to be cut at 3.65volt and a LiPo at 4.2volt.

Don't worry. As said, balancers only turn excess charge current into heat when the battery reaches 3.65volt. They stop working when you take away the charge current.
You should of course use the LiFePo4 BMS or a balancer on each cell.

No balancing circuit is bad. One cell could reach 3.65volt before others do, and that will over-charge that cell, resulting in a shorter life span. LiFePo4 can AFAIK withstand 4.2volt, but at a cost.

Hope this has answered some of your questions.
For more info go to the "batteryuniversity" website.
Leo..

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Thank you Leo! An awesome and thorough response! I salute you and thank you!

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Does it matter? Not all questions involve an Arduino and not in all questions it is relevant.

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