Boost , bulk and float ( 13,80 )

[frankz66]

Hi everyone, I wanted to know if any of you could better explain some of the behaviors of my 12v system.

I have 4 PV panels in series for 80 volts of VOC and 9 amps, an epever 6415AN and 4 AGM in parallel 12 v 440 amps total .

Use as boost parameters 14.50 volts ( no equalization ) , a float at 13.70 volts , a boost duration of 180 mn and a coefficient of -2 mv .

Normally in the evening at the cut off I find myself with 12.77 volts, in short, the batteries are almost charged. I noticed that under normal conditions, around 12:00 Pm the voltage is already at 14.50 and a little more and then around 15:30 (if the day is clear) the current drops and then goes into a float, keeping at a voltage of 13.30 - 13.60, in short, oscillating. Today I changed the float to the default one that provides 13.80 volts and I noticed that even if I use a load of about 100 w, with this maximum bulk voltage of 13.80 the batteries begin to absorb, in short, to give an example: if in the afternoon I have the load of 100 watts with a stable float of 13.80, I see that the power of the panels is also brought to 300 watts, as if the batteries still require some current. Is it possible that this epever float is a pseudo float as some users have written on the internet? I know that when the batteries go into float it should absorb little current, in my case 440 / 4 110 amp batteries, they should absorb a maximum of 2 amps for one.

 

[mikefitz]

It seems that your batteries are not fully charged. What you should see , whilst still in boost at 14.5 volts, is the current into the battery fall to less than 4 amps, this should happen in the boost duration period. ( there should be enough solar to exceed 4 amps)
If this is not happening, increase the boost duration to 3 hours, also perhaps increase the boost voltage to 14.6
Keeping the float at 13.8 volts would be a good idea.

The boost of 14.5, duration 2 hours, float at 13.8 is a best guess, and may not be what the battery actually needs.

The charge ,(boost) voltages and absorbtion, ( boost) duration, may not get the battery 100% charged and the float, 13.8 will 'top up' at low current, if there are enough hours. With an AC charger this will happen, the float volts could be applied for many hours, with solar there may not be enough hours left in the day.

Mike

 

[frankz66]

It seems that your batteries are not fully charged. What you should see , whilst still in boost at 14.5 volts, is the current into the battery fall to less than 4 amps, this should happen in the boost duration period. ( there should be enough solar to exceed 4 amps)
If this is not happening, increase the boost duration to 3 hours, also perhaps increase the boost voltage to 14.6
Keeping the float at 13.8 volts would be a good idea.

The boost of 14.5, duration 2 hours, float at 13.8 is a best guess, and may not be what the battery actually needs.

The charge ,(boost) voltages and absorbtion, ( boost) duration, may not get the battery 100% charged and the float, 13.8 will 'top up' at low current, if there are enough hours. With an AC charger this will happen, the float volts could be applied for many hours, with solar there may not be enough hours left in the day.

Mike

Thanks Mike, the duration of the boost is set to 180 mn. Maybe I could increase as you say to 14.60 volts . I wanted to do it for a long time to bring the 14.50 volts to 14.60 (similar to GEL batteries). The battery manufacturer recommends 14.50, but having the temperature compensation could I do it? By varying the risk of having the AGM batteries heated or can I do it? I am attaching the parameters to get your opinion And any compensation paremtro calculate .

 

[pollenface]

I use both boost & equalize @ absorption voltage sometimes with these Epevers to get 6hrs absorption. 180mins is often not enough.

 

[frankz66]

I use both boost & equalize @ absorption voltage sometimes with these Epevers to get 6hrs absorption. 180mins is often not enough.

Thank you, could you please send me a screenshot of your parameters?

 

[pollenface]

Thank you, could you please send me a screenshot of your parameters?

no not really, I'm 1000kms from home.

As per my previous post. I sometimes set equalize to the "absorption" voltage (same as boost) and add duration to lengthen the "absorption" stage if deep discharges are taking place.

 

[frankz66]

no not really, I'm 1000kms from home and my circumstances are different to yours

Thanks anyway.

 

[frankz66]

In the epever software, the default charging limit voltage = 15.00 volts parameter is mentioned.

In this parameter, what value should be entered? Iola I mean as the maximum voltage that the manufacturer should declare for the maximum battery charge . I do not have this value available to my battery, but only the maximum value (I recommended) of charge which is 14.50 volts, a compensation coefficient of 0.018 (I suppose it is 0.003 multiplied by six cells). Peiara by default therefore being AGM I inserted 14.50 volts in the boost phase, equalization 14.50 volts (same value because they should not be equalized), a charging limit voltage of 14.60 volts. But not knowing what value to enter is correct 14,60 volts or 15 volts?

 

[pollenface]

That's the maximum voltage under temp compensation. I would keep it below the "over voltage" shut down point of your inverter.