battery agm and % charge

[frankz66]

Hello everyone, I wanted to know how to calculate the full charge time of a c100 110 amp 12 v AGM battery. In the morning the charge takes place with an initial absorption of 8 amperes and reaches up to 19 amperes in peak solar hours. I know there are three phases of charge, boost, absorption and float. The behavior of the battery is always the same ie it absorbs almost 2 A, but clearly its charge I assume is around 70%. Considering that as far as I know, it takes a long time to get from this percentage to 100%. Is there a way to calculate it? Does the float phase trigger to perform the charge action from 70% to 100% ? Thank you .

 

[sunshine_eggo]

Hello everyone, I wanted to know how to calculate the full charge time of a c100 110 amp 12 v AGM battery. In the morning the charge takes place with an initial absorption of 8 amperes and reaches up to 19 amperes in peak solar hours. I know there are three phases of charge, boost, absorption and float. The behavior of the battery is always the same ie it absorbs almost 2 A, but clearly its charge I assume is around 70%. Considering that as far as I know, it takes a long time to get from this percentage to 100%. Is there a way to calculate it? Does the float phase trigger to perform the charge action from 70% to 100% ? Thank you .

C100 ratings are difficult to deal with.

C20 ratings are typically used for charge criteria.

What is the C20 rating of the battery?

Three charging phases:
Bulk = maximum current available while below absorption voltage.
Absorption = maximum voltage held while current tapers.
Float = maintenance voltage maintained to hold battery at 100% charge.



Because you are charging with solar and not charging at a constant current, it is nearly impossible to calculate charge time.

The way you can tell an AGM is charged is when the charge current while at the absorption voltage drops to 0.02C of the C20 rating.

Example:
100Ah C20 AGM battery.
14.6V absorption

When the above battery is at 14.6V and the charge current has dropped to 2A, the battery is fully charged.

 

[frankz66]

C100 ratings are difficult to deal with.

C20 ratings are typically used for charge criteria.

What is the C20 rating of the battery?

Three charging phases:
Bulk = maximum current available while below absorption voltage.
Absorption = maximum voltage held while current tapers.
Float = maintenance voltage maintained to hold battery at 100% charge.

View attachment 131612

Because you are charging with solar and not charging at a constant current, it is nearly impossible to calculate charge time.

The way you can tell an AGM is charged is when the charge current while at the absorption voltage drops to 0.02C of the C20 rating.

Example:
100Ah C20 AGM battery.
14.6V absorption

When the above battery is at 14.6V and the charge current has dropped to 2A, the battery is fully charged.

Thanks . Thank you as always for your answers. In your opinion, considering the parameters of the batteries, are the parameters I entered okay? Can you optimize something?

 

[sunshine_eggo]

Change 14.45 to 14.50
Change 13.75 to 13.80

 

[frankz66]

Change 14.45 to 14.50
Change 13.75 to 13.80

Technically why?

 

[sunshine_eggo]

Technically why?

They are within the battery spec.

They will allow for slightly faster charging.

 

[frankz66]

Despite being at night, the solar system is off, I noticed that there are 0.06 volts

????

 

[sunshine_eggo]

measurement error

 

[frankz66]

measurement error

Thank you for everything and the time you have dedicated to me.

 

[sunshine_eggo]

You're welcome!