Victron energy BMV 600 Manual De Instrucciones página 11

When no ratings are given at all, you can measure your battery using a
'constant load bank'. In this way a second rating can be obtained, together
with the 20hr rating which represents the rated battery capacity in most
cases. This second rating can be determined by discharging a fully charged
battery with a constant current; until the battery reaches 1.75V per cell
(which is 10.5 V for a 12 V battery or 21 V for a 24 V battery). A calculation
example is shown below:
A 200 Ah battery is discharged with a constant current of 20 A and after 8.5
hours 1.75 V/cell is reached.
So,
20hr rating,
Peukert exponent,
A Peukert calculator is available at http://www.victronenergy.com.
2.3.3 Charged-parameters
Based on increasing charge voltage and decreasing charge current, a
decision can be made whether the battery is fully charged or not. When the
battery voltage is above a certain level during a predefined period while the
charge current is below a certain level for the same period, the battery can
be considered fully charged. These voltage and current levels, as well as
the predefined period are called 'charged-parameters'. In general for a 12V
lead acid battery, the voltage-charged-parameter is 13.2V and the current-
charged-parameter is 4.0% of the total battery capacity (e.g. 8 A with a 200
Ah battery). A charged-parameter-time of 4 minutes is sufficient for most
battery systems. Please note that these parameters are very important for
t = 8 5 . hr
1
= 20
I A
1
C = 200
20 hr
t = 20 hr
2
200 Ah
I =
2
20 hr
log 20
n =
log 20
Ah
= 10 A
− log 8 5 .
=
1 . 2 3 1 . 2 3
1 . 2 3 1 . 2 3
− log 10
7