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.

You would expect a meter that shows battery capacity and energy usage to have no problem understanding Charge-Discharge. But it doesnt! It considers both directions the same! This means that it is useless to get a amp hours left value. or measure state of charge by watching energy in-out. The only meaningful value on the display is the fuel gauge. in that case. And the amperage value you have to guess if that is charging or discharging.

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.

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