Voltage Amp Meter DC, DROK Battery Monitor DC 0-300V 200A, Ammeter Voltmeter for Solar System Setup Power Energy Capacity Volt Current Detector Panel with Hall Sensor

So far this seems like a great meter. *except* it gets out of calibration over time. Needs to be reset (with 0A flowing through the sensor) from time to time to be useful.Some tips:1) To calibrate the current to zero (when no load present), press and hold the bottom button for a few seconds.2) To extend wiring you need 4 wires instead of 5 -- the center wire in the sensor harness is ground.3) Make sure to install the hall sensor with the arrow pointing towards the load end.4) When programming options, the unit won't "remember" the settings if you don't confirm them by pressing and holding the top button.Edit: changing to 2 stars because it requires recalibration quite often (a few times a day if you want any accuracy) - which is a pain because I need to take all load off the battery to calibrate the amp meter. If they fix this issue this meter would get 5 stars from me.

I am using this for an automotive application. Here's what I observed bench-testing the unit prior to installation -- indoors at room temperature: Current draw, backlight off: 6.1 mA @ 14.0 V Current draw, backlight on: 17.9 mA @ 14.0 V Meter accuracy, voltage: +/- 0.1 V, 0-15 V Meter accuracy, current: Unable to zero, unit always reads -0.1 A. Meter reads up to ~10% low for positive (discharge) current, ~10% high for negative (charging) current, over the range of +/- 5A -- the limit of my bench supply. The attached graph shows the current accuracy over this range. I hope it performs this well in the vehicle.The limited precision and accuracy of this meter, even in a relatively low-noise lab environment, means that it won't be useful for tracking parasitic discharge or trickle charging on a parked car's battery, for example. In fact, I would consider its current consumption on the high side for a continuously powered car accessory. But, it should still provide interesting and useful information about the voltage and charge/discharge rate during vehicle operation.I successfully swapped the LEDs in mine to match the rest of the gauges on my dash (2 x 0603), and wired them to my car's dash illumination circuit. This requires disassembly and rework.There is some sort of communications port (unpopulated) on the PCB, but I couldn't find any obvious access to the "alarm" signal for voltage too low. So the alarm only flashes the display, which is pretty useless. I wish they gave us access to the alarm signal, or other options for I/O.No comment yet on performance in-vehicle or reliability.

Well, I was in the question mode, got the meter, now how in the world do I program it. The answer after looking around on the internet and reading all sorts of reviews, I found that Amazon support keeps PDF files for there devices they sell, was able to contact them via support texting and ask for the file I needed. Was no real hassle to get once I found my road blocks in my computer, a simple download and made a hard copy for future reference. Hope this helps someone else too.

I got this for my travel trailer so I could monitor the battery use and charge. One installation tip I got that you might consider is to use CAT5 or CAT6 cable between the monitor, the Hall sensor, power, and ground connections. Yes, you can send 12v over these thin wires without worry. I used about 15ft of cable along with these connectors that made it even easier: https://www.amazon.com/gp/product/B07PR1LFVG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1.After installing this meter, I could not find the directions as to how to program it. But, I thought, how hard can it be. Well, as it turns out, programming the device is not the least bit intuitive.Searching the internet, including the DROK site proved fruitless. I resorted to reading all the Q&A and reviews to piece it together. And then, out of the corner of my eye, I saw a pdf link on the Amazon product page to the User Manual under Technical Specification just below the Technical Details section under Product Information. Here is the link to make it even easier for you: https://m.media-amazon.com/images/I/B1ubSSVdpyS.pdf.Read it VERY CAREFULLY. It really does answer most questions.Now, here is what I wanted most to know about programming, and perhaps you, too:1. AH stands for Amp Hours. FYI, for an inexpensive Interstate hybrid, deep cycle,12v, lead acid battery, group 24, that's about 60. If you have two for your trailer as I do, set this number at 120 as in AH1 20.0. Be sure to hold the square top button for a few seconds to make it stick. This whole thing should flash at you when it does.2. FU here stands for something other than what you may think. In this case, it is what your voltage reading should be when FULLY CHARGED . For a 12v system, like my trailer, that should be at least 12.6 for a healthy, fully charged battery. So I set this number to FU0 12.6.3. As for the other settings, I haven't bothered with them other than to make sure they were all set to '0' since I didn't want alarms going off.Hope this helps. Thanks for all the other reviews with tips, especially the one about holding down the square, top, right-side button to get the setting to stick.

Worked exactly as I expected it to. Nice to know the actual amount of Amps being used on different sources. It came with three choices in length of wire depending on your situation which helped me finish my job properly. I would purchase this product again and highly recommend it. It even has a controlled switch if you choose to have the light on or off to see better.

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