GERI® Volt Amp Voltmeter Ammeter 2in1 LED Digital Voltage Current Measurement Meter DC 5V 12V 4.5-30V/100A with Shunt Red +Blue

Just be aware it only measures current in one direction. Not suitable for a charging system. It is 0 to +100amps not -100 to +100amps. I should learn to read better. Aside from that it works fine but the display washes out in sunlight. Its good that it was not very expensive.

Very nice little meter. I'm planning on installing this in my 4Runner to monitor my total system draw as I add various upgrades. I was looking for a small meter that can fit into a tight console space and this looks perfect. I haven't installed it yet (just got it) but the bench test with my HHO rig worked well. I was getting slightly differing measurements using a multimeter and this device, [email protected] on the device vs [email protected] on the multimeter but it is within the margin of error for such a low draw. I like the lighting. The red /blue makes it easy to distinguish quickly and is visible in daylight but not obnoxiously bright at night. Mounts very flush. 1-2mm rim around the screen sits low. Didn't have instructions. Here's the breakdown.SHUNT- routes the power from your device to the ground while measuring the amperage. Place in line (series)on the negative side of your device. Mine will be between the battery negative and the chassis frame, measuring the draw of my electrical system.RED- powers the meter and measures the voltage of the device your measuring. Attach ahead of the device you want to measure the voltage of. I don't want the meter on 24/7 so I'm tapping my aux light add a fuse.YELLOW- measures the amperage at the high side of the shunt. Attach to the small screw at the positive side of the shunt.BLACK- ground and measures the amperage at the back of the shunt. Wire to the negative side small screw.

Does not come with directions so you will have to play around with it depending on your application to get it to work. My need was to see if a charging circuit on a Garden tractor was working properly because the tractor come with a ammeter that seemed to not work properly and it was a crappy unit to began with. Connection is black wire from meter to one end of shunt and Yellow wire to the other end of shunt and the red wire is spliced into a red wire within the system. I used the red wires going to the old ammeter to make that connection. Good Luck.

I'm using this for a hydrogen generator with a pwm so I can control the amps that go to it, and without this meter I would not be able too do this.OK the meter is in my car and sense the power is DC, I have too be able too control the amps, if it were not there I would have a water heater instead of a generator! They work with each other. If you don't have both of these products then you cannot control the generator!

Package well but amp not really accurate

wired in to our bicycle 12V generator project as diagram included in amazon posting shows, worked for about 15 seconds, then went dead, no display for amps or volts. Did not exceed 18 volts, volts seemed to disply ok, but amps never displayed above 0.0. either we cooked it with the slowly pedalling bicycle, or our particular unit is a lemon. i dont think we even exceeded 1/4 amp based on previous tests of the system with a multimeter and no load only producing about 1.9 amps. Product description should more clearly display a maximum sustained amp limit ALONG SIDE the amp range, or more fully explain what a <60mAmp "work current" only displayed in the product description means-either it only uses the 60mAmp to power the display, and it can accomodate currents up to 100 amps as the product names claims, or if you send a sustained current of more than 60 mAmps through, it cooks both the volt and amp part... i have a feeling we just were unlucky with the individual unit we were sent, we will probably put in for a refund or exchange.

Truly blown away! Never had ability to know amps as well as voltage! I really like this product! Seller is class A! Emailed me back about a question submitted and explained answer as well as sent diagrams of setup possibilities. Very dependable seller and highly recommend. Thank you!

works as advertised... 8th graders had no problem figuring out how to wire it up - after studying the last picture on Amazon. [kind of wish that was included in the packaging, but it wasn't hard to find the link again in the amazon account]