Hello All.
This is a wonderful community and I enjoy the opportunity to contribute.
Primary objective: Measure starting current drawn from automotive battery in automotive application in order to inform design and development of 12VDC batteries and related systems.
Secondary objective: Measure current draw on 12VDC battery that triggers Battery Management System (BMS) to shut off (close) draw from battery, in order to assess batteries for technical specifications and monitor stock to meet specifications.
Equipment at hand.
Some knowledge of electronics, physics and chemistry.
Large assortment of varying styles and capacities of batteries.
Hantek DSO1000 Series Handheld Scopemeter
'Heavy Duty' Shunt 200A, 50mV
Globe automotive, 55/60W 12VDC
Wire, etc.
Unfortunately I have little experience using a scope, even less using a shunt. I wanted to create a circuit where I measure the current spike connecting the globe to the battery, a somewhat miniature of my two objectives.
My diagram of miniature.
Shunt specs
Max. current 200A
Voltage at max. current 50mV
Shunt resistance 0.25mOhm
Accuracy 0.5%
Measuring mV across shunt I get 11.4 mV (by across shunt I mean -ve probe to battery side little screw, +ve probe to little screw globe side, with switch closed, globe lit.) Probes used for multimeter on scope.
Measuring Ohm's across shunt I get 0.1 Ohm's with switch open.
Measuring Ohm's across shunt I get 4.9 Ohm's with switch closed.
Ohm's Law states Current = Volts / Resistance
Current = 0.0114 / 4.8
Current = 0.0024
Is this correct? How can I confirm my findings?
I have read that I need to measure the difference across the shunt, by connecting one channel to the battery side of the shunt and one channel to the load side of the shunt. Each channel has the sharp measuring probe and the alligator clip (ground). Apparently then I can subtract one channel from the other in order to more accurately measure the voltage difference across the shunt.
How do I connect these channels in terms of probes and grounds, either side of the shunt to measure mV?
How do I then effectively calculate current? How can I cross reference my findings to ensure accuracy?
Thank you in advance for your contributions on my miniature and objectives on my project.
This is a wonderful community and I enjoy the opportunity to contribute.
Primary objective: Measure starting current drawn from automotive battery in automotive application in order to inform design and development of 12VDC batteries and related systems.
Secondary objective: Measure current draw on 12VDC battery that triggers Battery Management System (BMS) to shut off (close) draw from battery, in order to assess batteries for technical specifications and monitor stock to meet specifications.
Equipment at hand.
Some knowledge of electronics, physics and chemistry.
Large assortment of varying styles and capacities of batteries.
Hantek DSO1000 Series Handheld Scopemeter
'Heavy Duty' Shunt 200A, 50mV
Globe automotive, 55/60W 12VDC
Wire, etc.
Unfortunately I have little experience using a scope, even less using a shunt. I wanted to create a circuit where I measure the current spike connecting the globe to the battery, a somewhat miniature of my two objectives.
My diagram of miniature.
Shunt specs
Max. current 200A
Voltage at max. current 50mV
Shunt resistance 0.25mOhm
Accuracy 0.5%
Measuring mV across shunt I get 11.4 mV (by across shunt I mean -ve probe to battery side little screw, +ve probe to little screw globe side, with switch closed, globe lit.) Probes used for multimeter on scope.
Measuring Ohm's across shunt I get 0.1 Ohm's with switch open.
Measuring Ohm's across shunt I get 4.9 Ohm's with switch closed.
Ohm's Law states Current = Volts / Resistance
Current = 0.0114 / 4.8
Current = 0.0024
Is this correct? How can I confirm my findings?
I have read that I need to measure the difference across the shunt, by connecting one channel to the battery side of the shunt and one channel to the load side of the shunt. Each channel has the sharp measuring probe and the alligator clip (ground). Apparently then I can subtract one channel from the other in order to more accurately measure the voltage difference across the shunt.
How do I connect these channels in terms of probes and grounds, either side of the shunt to measure mV?
How do I then effectively calculate current? How can I cross reference my findings to ensure accuracy?
Thank you in advance for your contributions on my miniature and objectives on my project.