DROK Charge-Discharge Meter, 0-90V 100A DC Voltage, Amperage, Power, Battery Capacity Amp-Hour Watt-Hour Time Multimeter, LCD Digital Volt Current AH WH Watt Tester with Hall Sensor 2m Shielding Wire

So, the meter is fantastic, I use it to monitor my LiPO battery bank on my sailboat (attached picture - that was first draft installation).I attached what I think is the best part of the documentation - the part that tells you in a sense, how to calibrate the meter to your battery bank. I am not using the relay so I'm sure that's another nightmare.The Amazon page actually contains a link to the manual: https://m.media-amazon.com/images/I/B16YYqslmrS.pdfI also found a related manual for a similar DROK meter online: https://images-na.ssl-images-amazon.com/images/I/D1xd3n-y-DS.pdfHope this helps.

Its exactly 2 weeks since the monitor been in operation. It is very accurate when it comes to measuring the voltage and amps, you can even calibrate the meter for more dead on accuracy. The 'OUT' controls a 12 volt output which can be connected to a 12 volt relay or just a light. You can set the OUT to be enable/disable when a selected reading reaches a certain value. When it is disabled you have to manually switch on the output again. You have to firmly press the buttons to get a response, this is fine with me. I love Drok products, I got a lot of them...they always works but I'm not sure about this one, the capacity is not reading right.The main reason I bought this is to monitor the capacity (%) of the battery. As stated in the manual the "The capacity percentage is the ratio between the actual measured AH and the set AH." I got two 100 AH batteries in parallel so I set my AH to 200 but since the capacity only depends on AH my voltage will drop as low as 11.2 volts and the reading will remain 99% full the after a few minutes it will drop to 0%, I've never see it gradually increase or decrease.I've contacted Drok but didn't get a response as yet so I'm hoping they see this review and respond. I hope the fault is on me and not the monitor.

I was planning to use it for monitoring the car battery charging/discharging operation. As it says in the product description, “Bidirectional”, I expect the device shows a positive number when a current flows one direction, and a negative number in other direction. However, the display is not capable of displaying the negative sign, so it is not capable indicating which direction the current flowing. I suggest if this display is capable displaying multiple colors; use two colors — one direction displays in one color, and opposite direction displays in another color.As far as voltage and current accuracy, I felt good enough for my application.The product quality, it looks very cheapy; the bezel is flimsy, a paper thin thickness plastic protects the display area.

I use this to monitor the output of a rectifier style power supply that has no smoothing. The display jitters a little, but not bad. Measurements seem good.

As came out of box Calibration off a little. It is super easy to calibrate and work like a champ. Disconnect Battery power. Press OK and hold OK while powering up. The move curser to item to calibrate. use up and down arrows to match readings off another meter. press ok. Easy to read screen even with my old eyes. Would and most likely will buy another one.