Hi folks,

I have a 540AH battery powering an inverter. I want to work out how many AHs have been used since the inverter was switched on (only comes on in the evening when the solar panels have stopped working)

In a simple case, you could say it is C=A*T : 1A for 12 hours is 12AH.

As my load varies widely, this is not true any more.

I am measuring the current, via a shunt, every 500ms. Lets say it is 15A for a period of 500ms, that is 15A/ms. If the next measurement is 20A for 500ms, how do I add all this up to show me the current, cumulative AH used.

Its twisted my head...

I am trying to predict how much longer my 540AH battery will last with what has already been used.

note - Once I understand where I am going wrong, I will use the additional bits from http://www.powerstream.com/BB.htm based on load.

Thanks

Crispin

I have a 540AH battery powering an inverter. I want to work out how many AHs have been used since the inverter was switched on (only comes on in the evening when the solar panels have stopped working)

In a simple case, you could say it is C=A*T : 1A for 12 hours is 12AH.

As my load varies widely, this is not true any more.

I am measuring the current, via a shunt, every 500ms. Lets say it is 15A for a period of 500ms, that is 15A/ms. If the next measurement is 20A for 500ms, how do I add all this up to show me the current, cumulative AH used.

Its twisted my head...

I am trying to predict how much longer my 540AH battery will last with what has already been used.

note - Once I understand where I am going wrong, I will use the additional bits from http://www.powerstream.com/BB.htm based on load.

Thanks

Crispin

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