DC shunt for 24vdc 100ah battery current sense

Submitted by Guest on Mon, 15/07/2013 - 09:47

Guys i have 100A 75mV shunt resistor. i want to measure r sense the current from a 24vdc 100ah battery using it. Can anyone help me.. i already saw the DC shunt topic in the building blocks.. i tried the circuit for my 12vdc 7ah battery with the same resistance values.. but instead of LT1495 i used LM358 .. and the output i got is 0.71. i don't know y i got this value. Is it because of LM358 ah.. r anything else.. can anyone help me ... help me for 24vdc........... thanks in advance..

Re: DC shunt for 24vdc 100ah battery current sense

Submitted by Robert Wall on Tue, 16/07/2013 - 11:11.

I do not think a standard op-amp like the LM358 will work in that circuit. The LT1495 is special because it can accept input voltages above the op-amp supply voltage (5 V), the LM358 cannot.

You need to redesign the circuit to be able to use a standard op-amp like the LM358.

Re: DC shunt for 24vdc 100ah battery current sense

Submitted by K Santhosh Kumar (not verified) on Wed, 17/07/2013 - 06:24.

thanks Robert.. then i ll try to get the LT1495 itself...

Re: DC shunt for 24vdc 100ah battery current sense

Submitted by K Santhosh Kumar (not verified) on Wed, 17/07/2013 - 06:26.

Robert if u have any other circuit diagram means please upload it yar.... thanks in advance..

Re: DC shunt for 24vdc 100ah battery current sense

Submitted by K Santhosh Kumar (not verified) on Wed, 17/07/2013 - 06:59.

Hi Robert me just now tried the circuit using LM1458N opamp instead of LM358 .. i got the output around 2V. the battery which i used for sensing is 12vdc 7.5ah .. the shunt resistor which i used is 100A 75mV .. the circuit which i am using is here .. http://openenergymonitor.org/emon/buildingblocks/dc-shunt ... but i didn't make use of that RB resitor and capacitor.. since i am not going to use the arduino board... the theoretical and practical values are different. r the calulation which i am doing is wrong r anything else is wrong r i have to use oly the LT1495 ah...i don't know .. Please do reply for this man.. it ll a great help for me.. thanks in advance...

Re: DC shunt for 24vdc 100ah battery current sense

Submitted by Robert Wall on Wed, 17/07/2013 - 12:30.

Read again what I wrote about the LT1495. LM1458N != LT1495

This Linear Application Note has the circuit and full details, so I am sure it will work if you use the correct components. There are many other circuit ideas in there too.

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