Clamp-On Current Meter Readings

mena661 wrote:

Matt_Colie wrote:
AZ,

DC current probes are notoriously inaccurate.

Aren't the clamp-ons hall effect? Are those inaccurate too? Also, how inaccurate are they? My meter has an accuracy rating, are those typically incorrect? Sorry for the questions this is the first I've heard of this.

Hall device sensors can be very accurate. Without knowing what brand/model you have it's hard to tell what the accuracy is.

However, if your dc current meter has a hall device rather than a shunt. (Hall are pretty typical today, can find a 250A hall current probe from many sources) a decent one is plenty accurate for RV measurements.

If it is a reasonably quality vendor trust the accuracy readings. Remember with a hall current probe, especially if you are looking at currents under 10A or so, use the autozero function with the probe oriented how you will connect and near the connection point but not around the conductor. This will zero out much of the external magnetic field. On a good meter if you autozero then take a reading without putting it around the conductor, it shouldn't read more than about 0.3A, often less. And even if you don't autozero, the reading should be less than 1A or so.

If your measuring 50, 100, 200A, the need to autozero, isn't near as critical.

How accurate??? again depends on model, but 5% of reading or better is achievable at reasonable cost. And that's probably "good enough" for RV measurements. Repeatability on most is going to be well better than 5% of reading.

menna:

BTW I have a 1000A (yes one thousand) AC/DC clamp on True RMS current probe with peak hold function. When measuring the DC current in my solar charger, or battery charger and comparing it to the trimetric reading the difference is usually in the few 0.1A at currents up to about 40A, at most an amp at 100A charging current. using it on my Vector battery charger also yields readings that are very close to the Vector current reading, within an amp.