Overkill Solar BMS Balancing current?

[snoobler]

@OverkillSolar

Looked at the BMS website. Looked at the manual. Searched the forum, but WAY too many things to sort through. Probably missed it somewhere, but I really did try. Questions:

1. Active or passive balancing?
2. Current?

Thanks

 

[Mex Rider]

@OverkillSolar

Looked at the BMS website. Looked at the manual. Searched the forum, but WAY too many things to sort through. Probably missed it somewhere, but I really did try. Questions:

1. Active or passive balancing?
2. Current?

Thanks

It is passive and could be / should be set to "balance when charging" but can be set to always be balancing, not recommended.
Don't know current but will see if I can find out

 

[nwillitts]

It is passive and could be / should be set to "balance when charging" but can be set to always be balancing, not recommended.
Don't know current but will see if I can find out

whats wrong with always balancing?

 

[newbostonconst]

I was making a chart of them all and couldn't find it either....

	Balance Amps
Daly	0.04
TOP	0.1
Chargery	1.2
Ebay 1.2 Amp	1.2
Ebay 5 Amp	5
Overkill	NA

 

[nwillitts]

i have paralleled 3 24v overkill solar BMS together with 3 sets of batteries @100AH and they balanced each other while i watched using blue tooth monitors.it went across all batteries.very cool.
then i charged them all at once and it worked fine.
gonna add another battery pack for a set of 4.

 

[Mex Rider]

whats wrong with always balancing?

Balance only when Charging
When enabled, the balancing routine will only be performed when charging.
When disabled, the BMS will enter Static Balance mode, where it will balance when both
charging and discharging.
NOTE: Charging while balancing is usually more effective, because the cell delta is greatest at
the top of the charge. We recommend to keep this setting enabled.

This from the manual, I'm only a newbie

 

[Mex Rider]

Balance only when Charging
When enabled, the balancing routine will only be performed when charging.
When disabled, the BMS will enter Static Balance mode, where it will balance when both
charging and discharging.
NOTE: Charging while balancing is usually more effective, because the cell delta is greatest at
the top of the charge. We recommend to keep this setting enabled.

This from the manual, I'm only a newbie

DZL says:
50 mA (I believe)
Charging current

 

[On_The_Road]

So, what was the definitive answer on what's wrong with always balancing?

 

[JoeHam]

So, what was the definitive answer on what's wrong with always balancing?

It just burns a bit more power but does a better job of getting the balance job done, especially with a low balance current BMS.

I’ve just converted to balance all the time with my old Chargery which has a low balance current and so far I’m happy with the choice.

 

[On_The_Road]

I'm guessing the current used by the BMS won't be counted for SOC calculations?

But if each cell is drawing 70ma x4 it's not that much ?

 

[JoeHam]

I'm guessing the current used by the BMS won't be counted for SOC calculations?

Correct. Only current going through the shunt can be used to calculate SOC.

 

[time2roll]

So, what was the definitive answer on what's wrong with always balancing?

Generally nothing. Usually balancing starts at delta 15 to 20 mV and all the cells should be within that range while in use. As the battery approaches full charge is when the differential starts to show and balancing will start. Only issue is if the battery becomes very low the balancing will also activate and potentially spoil the top balance. VERY slow process so generally not an issue.