0-80A Automotive current meter

[alphi]

Compact 0-80A Automotive Ammeter
The latest adddition to our line-up of PIC-based automotice projects. Build it and keep tabs on your car's electrical system.

 

[cozturk]

You can measure it by measuring voltage on accu cable!!

 

[david90]

how do you get current from measuring voltage? Ohms law?

 

[cozturk]

The cable is resistor. about 0.001 ohm. For 80A the voltage is I x R = 80mV.

Your uC can calculate current via this formula or you can use a voltmeter by calibrating multi turns trimpot. For example you can use 70107 voltmeter circuit. It has 200mV full scale.

Perhaps you may need a op-amp multiplier for scaling .

 

[eduponto]

Please:

can upload Silicon chip Australia article or schematics clamp meter adapter for multimeter.......




Thanks in advance.

 

[nec3]

You can measure it by measuring voltage on accu cable!!

you never know or measure the real rezistance of that cable!

 

[cozturk]

Ok. But it is not necessary to know exact value of current! even 5% sensitivity enough for automobile panel. 30A or 31.3A not important. This panel is not scientific meter. also you need calibrate it by real multimeter for first time.