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    Current monitor/sensor

    Yes, but what with 5V voltage drop on 0.5E dischatge resistor? Is this nedd to take into account, or? Now i tasted with 4A, so 2A only through each mosfet and i measured 75degree per C on heatsink so from calculation is junstion temperature is allowed range. Is that not truth?
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    Current monitor/sensor

    Hello, ia have one question regarding heatsink temperature, so i have two IRFP460 mosfet on pretty big heatsink en testing on 4A current and i measured temperature on heatsink after one hour arround 80 degrees, so high. I made calculation and says: P_Dmax=5A*(12V-(5A*0.1Ω)-5V)=5A*6.5V=32.5W...
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    Current monitor/sensor

    Maybe because missing capacitor on ADC pin to hold voltage??
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    Current monitor/sensor

    If i burdened battery or. increase discharge current reading of voltage becomes smaller. I have 33kE and 11kE resistors serial from battery + pin to ground, so this is resistor divider, so if no current flows from battery there is normal reading, when current is higher reading is wrong or...
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    Current monitor/sensor

    I finally figured out where has problem been all the time, ground noise because battery connector. PWM signal is on picture below and you can see oscilating on ground. I solved this by putting 0.47uF capacitor between battery connector and signal is smooth and now voltage on -pin is the same...
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    Current monitor/sensor

    Thanks but i gave an example of measurements in previous posts, mosfets are IRFP460, so only problem is that voltage on - pin does not follows voltage on + pin, regarding mosfet transistor Vds should not be a problem for this case. I wondering why voltage on - pin is lower than voltage on + pin...
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    Current monitor/sensor

    I measured 5.5v on op output when input voltage is 1v, then voltage on r4 resistor is 0.75v, current is 1.6a, power supply voltage was set on arround 11.8v. So if increasing voltage of power supply (which represent battery) than current is increas to arround 1a and than stops increasing which...
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    Current monitor/sensor

    I am using mosfets IRFP460, regarding datasheet these transistor are suitable for project, i will check LM324 output voltage and then report values. However problem is that battery voltage is reduce by high current so theoretically when 10A is flows out of battery, 5V is on R4, battery voltage...
  9. D

    Current monitor/sensor

    So i have changed filter and improve ground and provlem with currenr spikes is now solved. I was testing circuit with power supply instead of battery and i figured out that current decreasing with bat voltage decreasing which is not allowed, maybe because too small mosfet drain to source...
  10. D

    Current monitor/sensor

    Ok i sould adding resistor. So, do you still think that the signal spikes represented on picture above is reflected by poor ground, i must perform test once again i add some kind of "star" ground so all gnd is connected at one point with thicker wire.
  11. D

    Current monitor/sensor

    This is schematic you suggested me, only different is that there is no 22E resistors to mosfet gates.
  12. D

    Current monitor/sensor

    , So i forgot to tell you that i have separate PCB board, one is power board and one is control board and only thin wires (flat cable) connecting them together so this is the main problem i must provide low resistance ground. I have other question, why voltage on -op pin is not equal (aprox...
  13. D

    Current monitor/sensor

    I placed thicker wire in some ground places in order to avoid voltage drop as you said above and also put the thicker + and - connection wire for battery connection and problem solved when discharged current to above 2A is flowing, but when increasing current using PWM modulation as described...
  14. D

    Current monitor/sensor

    is this parasite capacitance? otherwise i solved problem with thicker positive and negative wire for battery connection but wires must be close together, if they aren't effect of capacitance appear again!
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    Current monitor/sensor

    With spacing between battery wire (+ and - cable), signal is increasing it's shape like above, when wiring of battery so close together ther is just some little spikes appear on signal how can i avoid this problem, how can i get dc signal on discharging resistor while battery being discharged.
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    Current monitor/sensor

     TNX for your help audioguru I try with better ground and there is no such a signal as above any more!! This was solution, I have very thin ground connection between battery ground and mcu ground so I add thicker wire.
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    Current monitor/sensor

    Thicker ground wire?? Where exactly?? Circuit is very simple to understand but i have bad dreams about this unstable working :-\ ^-^ So i made some onother measurements with scope and i figured out that when i put bigger resistor in rc filter, for example 1ME (1ME and 100nF) thern i have...
  18. D

    Current monitor/sensor

    Yes, but why this happening when I try to discharge battery through 0.5E resistor, current is controlled with software regulated PWM output, is this signal appear because OP oscillate via feedback?? I just wondering how to always provide DC signal to load resistor to ensure that always flow...
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    Current monitor/sensor

  20. D

    Current monitor/sensor

    i testing also direct on pwm pin od MCU and when battery is charging there is a lot of noise in ground, in upper case is 10% duty cycle so i don't know if that kind of signal is reflected by RC loos, or?? Maybe OP is critical here in this circuit??
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