watts up meter
 

I bought one of these this winter and rigged it today with my little 15 amp solar panel. Works pretty cool and relatively inexpensive. Tracks amp hours down to three decimal points. I rigged it with quick disconnect plugs between the controller and battery terminals and got a much more revealing set of data than I can with just my multi-meter, including: cumulative amp hours, amps, voltage, watt hours, etc. Its fun to adjust the panel and see exactly the change I may or may not be getting given the angle of the panel to the sun and what happens when a cloud drifts by. It also revealed how "cheap" my little controller is as it would never kick out more than 12.78 volts . I recommend it to those of you who like to mess with solar and don't already have a more sophisticated "shunt" type meter. This does not use a shunt.

Amazon.com: "Watt's Up" RC Watt Meter & Power Analyzer WU100 Version 2 --- SALE!: Toys & Games

Rick

Are you sure about that? Everything that I have read about the Watts Up meter (and other knock offs) leads me to believe that it uses shunt resistors. The other way I know of to measure current uses coils, similar to the clamp on type meters, but those current sensors are more expensive.

This page for example; Meter Special Modifications

I'm not sure. It was my assumption based n the fact it is a very small device and there were no external shunts to run connections through. However, I really do not know the specifics of the internal working nor am I knowledgeable enough about electronics to to make an informed opinion on how it really worked if I did know what was inside. However, I had gotten the impression it didn't work with a shunt but I certainly could be mis- informed.---- and now, after reading that link, it indeed appears I was mis-informed. Thanks for the heads up.