I bought this meter abroad as I needed one in a hurry it was not very expensive ,and has lots of functions.The instructions were not in English ,but it served its purpose ,I had noticed a battery symbol on the display but did not realize exactly what it meant.
The other day I used it ,and it was reading about twice what it should of ?
So I replaced the PP3 battery this fixed it ,when I checked the battery I had taken out it read 7.8 volts ,so I put it back ,when I checked it under load it was 3.5 volts.
So it goes to show what effect the internal resistance (esr) has when you actually put a battery to use.
I knew about the internal resistance of a cell from my training many years ago,but I did not know it was more complicated than I was taught. It is the sum of a number of resistances which makes it quite complex . This explains why on a vehicle battery (lead acid) it has voltage , amp hours ,and it states a time (normally 20 Hours) ,which I understand is the correct way to check the actual capacity of the battery.
Barry Wilkins
The other day I used it ,and it was reading about twice what it should of ?
So I replaced the PP3 battery this fixed it ,when I checked the battery I had taken out it read 7.8 volts ,so I put it back ,when I checked it under load it was 3.5 volts.
So it goes to show what effect the internal resistance (esr) has when you actually put a battery to use.
I knew about the internal resistance of a cell from my training many years ago,but I did not know it was more complicated than I was taught. It is the sum of a number of resistances which makes it quite complex . This explains why on a vehicle battery (lead acid) it has voltage , amp hours ,and it states a time (normally 20 Hours) ,which I understand is the correct way to check the actual capacity of the battery.
Barry Wilkins