Proper process for balancing two Dyness batteries

wingnut771 said:
The one on the right is getting discharged the least. It has more leds.
Click to expand...
No, it is getting discharged the most and charged the most. Read the Victron screen shot. That one has the shortest leads and will supply and get charged with the most current because the resistance is the least on that battery.
 
denmendez65 said:
No, it is getting discharged the most and charged the most. Read the Victron screen shot. That one has the shortest leads and will supply and get charged with the most current because the resistance is the least on that battery.
Click to expand...
The right battery will get charged quicker than the left one.
 
denmendez65 said:
No, it is getting discharged the most and charged the most. Read the Victron screen shot. That one has the shortest leads and will supply and get charged with the most current because the resistance is the least on that battery.
Click to expand...
That's the theory. Why is the one on the left getting to full led 100% along with the right one and then getting to 2 leds while discharging before the one on the right?
 
wingnut771 said:
That's the theory. Why is the one on the left getting to full led 100% along with the right one and then getting to 2 leds while discharging before the one on the right?
Click to expand...
I cant say for certain of course, but my theory is that it never gets full. It has already been discussed that the LEDs arent that accurate. So the battery on the right gets fully charged first and the one on the left is not getting all the way there.

The drift is gradual, over time the one on the left will not hold its charge because it is never getting full. The moment you start discharging and the artificial charge on the second one is gone, it will indicate a lower SOC than the right one.
 
denmendez65 said:
I cant say for certain of course, but my theory is that it never gets full. It has already been discussed that the LEDs arent that accurate. So the battery on the right gets fully charged first and the one on the left is not getting all the way there.

The drift is gradual, over time the one on the left will not hold its charge because it is never getting full. The moment you start discharging and the artificial charge on the second one is gone, it will indicate a lower SOC than the right one.
Click to expand...
If it gets to 57.6V then its full.
 
denmendez65 said:
And how is that measured? When connected to the other battery? When you have just pulled it off the battery bank? Most of that is superficial charge.
Click to expand...
They're in parallel. They'll both be 57.6V. The battery cannot absorb any more at this voltage. Its even fully charged at 55.2V but that voltage will need absorption time which it gets 2 hours already which is plenty.
 
wingnut771 said:
They're in parallel. They'll both be 57.6V. The battery cannot absorb any more at this voltage. Its even fully charged from 55.2V.
Click to expand...
Just because you read 57.6V across a battery bank does not mean all the batteries are full that are connected to it.
 
wingnut771 said:
Yes they are, there is no voltage drop when there is no load. See my edit.
Click to expand...
You can't do that. You will read the average voltage across all the batteries. The only real test is to disconnect each and leave them standing for a few hours and measure.
 
denmendez65 said:
You can't do that. You will read the average voltage across all the batteries. The only real test is to disconnect each and leave them standing for a few hours and measure.
Click to expand...
a dyness LFP battery is 100% charged between 55.2V to 57.6V. So if one battery is at 57.6V then the other is not far behind. There will never ever be a 2V difference between the 2 at that voltage.
 
wingnut771 said:
a dyness LFP battery is 100% charged between 55.2V to 57.6V. So if one battery is at 57.6V then the other is not far behind. There will never ever be a 2V difference between the 2 at that voltage.
Click to expand...
Just needs to be 1V, and you will have a 20% difference in SOC between 20 and 90% SOC.
 
denmendez65 said:
I cant say for certain of course, but my theory is that it never gets full. It has already been discussed that the LEDs arent that accurate. So the battery on the right gets fully charged first and the one on the left is not getting all the way there.

The drift is gradual, over time the one on the left will not hold its charge because it is never getting full. The moment you start discharging and the artificial charge on the second one is gone, it will indicate a lower SOC than the right one.
Click to expand...
the battery has to get full at some point , can use eskom to charge it full , it just takes one charge cycle to get them balanced initially and then you can monitor from a full state what it does

balancing only happens at full voltage very little current flows in paralel if at resting voltage imo
but yea even in this video he has the longer distance setup , charging cables go to bottom battery and each battery is further away from the charge source the higher they go in the stack
only charge behaviour , not showing behaviour on discharge

 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X