Connecting multiple balancers?

SlimyLemur56

New Member
Joined
Feb 20, 2020
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I've got 4 lifepo4 cells and a daly 80a bms I bought about a year and a half ago, I just repaired the cheesey m4 terminals that I stripped before I could ever use it once and am finally putting it together (for the first time, no experience with this). I have an ISDT Battgo BG-8S that I want to attach to get visibility into the relative charge state of each of the cells, but it also has balancing functionality. The BMS itself is also advertised to have balancing functionality (although not sure how much I trust it). This got me wondering if it's bad to connect the cell meter while the BMS is attached. Like probably neither have perfectly precise voltage measurements and they might fight each other trying to balance the battery to their own perceptions.

Is this an issue? Should I avoid connecting the cell meter? Should I connect the cell meter but never use it's balancing ability? Am I making something out of nothing?
 

sunshine_eggo

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Oct 26, 2021
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You are making something out of nothing. The balance currents involved are very low, and they will typically work together fairly well.

However, it is optimal to restrict balancing above 3.4V and only during charging when possible to retain a good top balance. Balancing at lower states of charges/voltages can undo a top balance.
 

Short_Shot

Photon Sorcerer
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Jul 13, 2021
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Balancing shouldn't be necessary for decent cells, but if you can disable the Daly balancing go for it. If not, just send it and see. It won't break anything but it might cause a conflict.

If you can disable balancing on the other device, you could do so if you see an issue.

This sounds like a perfect application for a smart BMS though rather than two devices lol
 

SlimyLemur56

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Feb 20, 2020
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Yeah I keep looking at the smart BMS's which are basically the same BMS I currently have just, in the time since I got this and havent used it, the smart monitoring has been added. I'm tempted to just buy one of those, but it means I wasted about $150 bucks 2 years ago...

But thanks for alleviating my concerns!
 

Mudd

Solar Enthusiast
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Oct 21, 2020
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you're making something out of nothing in my opinion. Top balance cells and hook up Daly. I'm also running a dumb Daly 100a keeps my 280ah cells very well balanced. The dumb daly is really a great BMS in my opinion. It's no frills protects the batteries balances perfectly well if you do a proper top balance.
 
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