DC Multifunction Battery Monitor Meter, 0-200V 0-100A LCD Display Digital Current Multimeter Voltmeter Ammeter for Cars Rv Solar System

I am using it for a dingy with 55 lb trolling motor and a 50 Ah LiFePo4 battery, and it is perfect for this role. 1. all info you need on one screen - voltage, current, Ah/Wh, remailing capacity. Having battery internal resistance and load resistance computed is also very useful. 2. it memorizes accumulated values (Ah/Wh) when powered off - no need to use an optional backup source. You manually reset these values after fully charging your battery. 3. it also measures all parameters when charging (charger connected to "load" terminals) - so you have exact Ah/Wh pumped into the battery even when your charger doesn't show it. Overall, a well designed device. Instructions in English good enough, readable and clear.

Arrives in a nice package with meter, shunt, wires, and instruction sheet. Unit is small, smaller than you might think from the picture. Which can be either good or bad. Instruction sheet reasonably clear on hookup. Except it doesn't say how/where to connect charger. The ammeter is unidirectional, which seems to mean current flowing in either direction gets added. Which in turn means the counts on AH and WH increase as a result of current flow in both directions. I think this means that if you connect the meter like the load, the counts will increase as you charge, and increase further as you discharge. And if you charge and discharge simultaneously, the counts will increase based on the net. Alternatively, you could connect the charger directly to the battery, in which case the meter would only count discharge loads and ignore any charging. Or you could get two meters, with one and its shunt for the load and the other and its shunt for the charger. Instructions obviously translated from Chinese. Good enough if you have a basic idea of what you're doing anyway. Some notes: a) the unit has label "External resistance", which seems to be listed as "Impedance" on the instructions. b) the instructions use the term "Bring load voltage", without defining it. Presumably this is the voltage across the load at the current point in time. c) Internal resistance is defined as (full voltage - bring load voltage) / bring load current", which maybe means drop from full voltage to now voltage, divided by now current - but I'm not sure what sense to make of that quantity. The voltage range (min and max, for showing battery bar graph) and current range (max, determined by shunt in use) can be set by alternating between long and short presses of the single front panel button. Which is small and requires a screwdriver or pencil or such. Similarly, the AH, WH, and run time counters can be reset. Meter has two modes, working mode and dormant mode. Dormant mode shuts off the backlight display and stops all measurements and calculations. Instructions report power consumption 0.031.2W in normal mode, 0.5mw-0.5W in dormant mode, dependent on voltage value (higher voltage, higher power). Don't yet have a sense for accuracy. Lots packed into a small meter for a low price.

I purchased the 100amp version and was pleasantly surprised by the accuracy - even when running a 0.5amp load.. Accuracy was confirmed for current and voltage readings with calibrated multimeters. Easy setup, the diagrams in the instructions are very clear and are conveniently reproduced on the back of the meter itself. The meter frame has snap fit tabs for mounting in a panel, cabinet or case. The interface for setting the meter to the correct voltage range for your batteries (which you must do to get accurate state of charge info), clearing readings, etc is a little fiddly and inconvenient, but works just fine. Keep in mind this is a meter only, it will only take measurements of how much power passes through it, it isn't smart enough to track charge/discharge, and will not do anything to prevent over charge or overdischarge of your batteries.

Using this on my trolling motor. Works well. Current is fairly accurate but voltage measurement is off by 320mV according to my Fluke multimeter. No function to calibrate. Can not measure reverse flow of current. (AH reading always increasing regardless if draining or charging the battery.) Will be nice for bar graph to show SOC instead of battery voltage.

WILL NOT WORK WITH A LOAD, OR ANOTHER POWER SOURCE. does NOT INCLUDE ALL WIRES TO SET UP AND FUNCTION! nO CLEAR INSTRUCTIONS. aMAZON DOES HAVE INSTRUCTIONS ON AMAZON LIVE. i DON'T EVEN KNOW IF IT WORKS.

The manual is written in horrible Chinglish, no surprise there. If you could program a VCR or alarm clock, you shouldn't have any difficulties with this one even without any instructions. It's basically one button with 2 choices - short and long press. But the voltage this gadget displays is consistently 0.2v higher than both my built-in voltmeter and the standalone multimeter show. So while it's easy to make an adjustment (in my head), I'm not sure I can actually trust it with the current (A) measurement. So one star off for the useless manual and one for the inaccurate reading.

This was easy to install and provides much better information than the simple 4 dot battery level on our camper.

This review is for the 100A model tested with 3.2V, 320 Ah LiFePo4 bank and 12v 60Ah car battery measuring charge current. 12V Battery: Current reading is consistently 2-3% low from 0 to 10A when cross checked against both my Fluke 289 and 189 multimeters and 4% low at 20A using another shunt known to be .05% accurate. Did not test anything higher but I would assume further decreased accuracy at even higher currents. This is below the advertised accuracy of 1%. There seems to be some bizarre ground loop anomaly that causes a false 40 to 60 mA reading when the positive battery terminal is disconnected from the shunt and any sort of external power supply/charger is connected to the negative lead, even when it’s a floating power supply. 3.2V Battery: You have to hook up an external power supply when the voltage is below 8v so this is absolutely useless for use with a standalone single or double cell LiFePo4 pack or 6V SLA battery. However I tried using it with a 3.2V battery bank and additional external 12v power supply per the instructions and got some really strange behavior. The charge rate was measured somewhat accurately, but low until about 6A, then from 6A up the readings were all over the place with error as high as 100%. The device completely malfunctioned. Not For Ebike with regenerative braking: Another limitation that others have mentioned is that this reads both positive and negative current flow as positive. This means that this device will not work properly with an E-bike that has regenerative braking. User Interface/Functions: As for the actual functions, display and user interface. I like that its easy to scroll through the settings with a single button, but I don’t like that you have to reset the Ah, Wh and run time separately. It takes a total of 6 long button presses and 9 short button presses (L,S,S,L,L,S,S,S,L,L,S,S,S,S,L). Please redesign this thing to make reset all the first menu option. Amazon would not let me upload photos. Bummer.