Help with shunt ammeter
I just got one of these from ebay: I am trying to read V and Amps while charging a battery on the bench. I have the shunt attached to the negative battery post, and the charger clamped to ...
Forum Discussion
Big Katuna wrote:
So,lets understand how a shunt works. It doesnt matter how many volts are going thru it. It drops so many millivolts per AMP, usually 50 millivolts (not always) per its rating.
For simplicities sake, let's say this is a 50 mV, 50A shunt. The meter is a millivolt meter.
So if you are passing 7 Amps, you should read 7 mV between the little screws.
The voltage drop has a plus and a minus. You can use a cheap Harbor Freight DVM to check this. My guess is the meter is not connected correctly or it doesn't like all the noise and spikes the battery charger is putting out.
If its a 100A shunt, 1 mV equals two Amps. You need to figure this out.
OK, I will check this in the morning. It's a 75mV shunt, supposedly.
