Boat alternator charging log calculator

Calculate integrated measured input charge and estimated added stored charge with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use integrated measured input charge and estimated added stored charge to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Measured sample times (hours)
0,1,2,3
Measured charging currents (A)
30,20,10,5
Initial stored charge (Ah)
50
Charge efficiency fraction
0.9
Integrated measured input charge (Ah)
47.5
Estimated added stored charge (Ah)
42.75
Estimated ending charge (Ah)
92.75

Try another scenario

Measured sample times (hours)
0.1,1.0,2.0,3.0
Measured charging currents (A)
30,20,10,5
Initial stored charge (Ah)
50
Charge efficiency fraction
0.9
Integrated measured input charge (Ah)
45
Estimated added stored charge (Ah)
40.5
Estimated ending charge (Ah)
90.5
Calculation method

Calculation method

Integrated measured input charge (Ah)

Trapezoidal current integration, times increasing; stored addition=integral×efficiency.

Estimated added stored charge (Ah)

Trapezoidal current integration, times increasing; stored addition=integral×efficiency.

Estimated ending charge (Ah)

Trapezoidal current integration, times increasing; stored addition=integral×efficiency.

Symbols and units
a
Measured sample times (hours)
b
Measured charging currents (A)
c
Initial stored charge (Ah)
d
Charge efficiency fraction

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • No battery-capacity clipping or state-of-charge calibration; measured current at chosen system boundary. Supported limits: All required fields must be finite values of the exact declared type and within displayed bounds. Lists contain1–1000 finite numbers. JSON tables are numeric rectangular rows, at most100 rows and30 columns; individual tools have stricter shape/domain constraints. No battery-capacity clipping or state-of-charge calibration; measured current at chosen system boundary.
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