Battery Monitor, Voltage Capacity Tester 12V 24V 36V 48V 60V Battery Capacity Indicator Iron-Lithium & Lead-Acid Battery Meter Voltage Capacity Percentage Indicator

I have included a chart that does not come with this unit, but should.Anyway, I found that you have to IGNORE the chart (cell count) but use the chart for reference to get the correct battery type (lead acid, Lithium Ion ect.)My experience is that I had to set the unit to read 2 cells even though the battery tested is 6 cells.The microprocessor needs to know the type of battery, and how many cells to sample.HOWEVER it is some how wrong on all 4 units I bought.The only reading I get on ANY OTHER cell count is 100% or 0%So here's what I had to do:I had to set the unit to the battery type. (In my case Lithium Ion)Then I had to select c1 (c for lithium, cell count 1) I tried 6, as it is a 6 cell battery and it didn't work.So I went from one to 18, and well ALL the settings but C2 Worked.I am also using this for a 7.4v Powerextra relacement for the Sony NP-F960 battery (with USB and Power Out)It works FINE.NO issues and accurate.It gives me the same reading on the unit as it does on the battery charger.So just select your battery type, then go through the cell count until you get something close to your reading on the charger, you kinda can't mess up because it will be the ONLY thing that isn't zero or 100%, unless your battery is totally dead or fully charged you can't mess it up.I hope this helps you guys out!

As a very active electronics hobbyist, I use a lot of batteries and battery packs. I generally use two types of batteries here – a 12 volt lead-acid “gel cell” as well as Lithium-Ion battery packs with differing number of cells depending on the voltage I need. I bought this battery voltage monitor to add to one of my battery packs so I could easily see the battery pack condition.The unit was shipped inside a cute little cardboard box, inside a padded envelope. It arrived in perfect shape with no damage. Included in the box was the meter, a pair of wires connected to a plug, a piece of foam to cover the back of the meter, and four mounting screws, two of a round head style, and two of a flat-head countersunk style. The unit did not come with printed instructions, but instead had a sticker with a QR code, directing the user to scan the code for a link with the instructions. Instead, I simply used the instructions in the Amazon product description.Following the instructions, I had no issue setting the unit up for either a 12 volt Lead-Acid battery, or various number of Li-Ion cells. There are some reviews here that claim that the instructions are wrong, but I found the instructions in the Amazon product description to be perfectly accurate: Hold the button down, apply power, release the button, then use the button to select the proper battery type and number of cells. 1P is a 12 volt Lead-Acid, 2P is a 24 volt Lead-Acid, etc… 1c is a single cell Li-Ion, 2c is a two cell Li-Ion, etc…Note that the unit is rated for a minimum of 8 volts. This is important – the unit will power-up from a single fully-charged 4.2 volt Li-Ion battery, but without the backlight, as the voltage is too low. You can set it to single-cell Li-Ion battery with a “1c” setting, but the unit won’t operate properly, as the voltage is below the 8 volt minimum. If you set it to a “2c” setting and connect it to a 2 cell Li-Ion pack, the unit will work properly, but below 8 volts, the backlight gets very dim. So a 3 cell Li-Ion pack is probably the lower-limit number of cells for this unit.Other reviews mention that the backlight only stays on for a short time. In my testing, I found that it will turn on when first powered and does not turn off. I’m not sure if maybe the design of this unit has changed over time, but as of this writing (late August 2020), the backlight stays on all the time, with the exception of when battery voltage falls to 0% - the unit turns off the backlight. This is very smart – as the unit with the backlight draws about 5 mA, but with it off, it’s so low I can’t measure it.Monitoring battery pack state of charge (% full) by measuring voltage is very difficult – there are many variables and parameters that impact the measurement. For instance, a full charged Li-Ion cell measures 4.20 volts, while that same cell, with a 1.5 amp load on it, now drops to 3.90 volts or so. To see how accurate this meter was, I did some testing using the 1P setting and 3c setting, applying different voltages to see how full the meter would indicate. The results are shown in the graph picture.In my opinion, this meter does a very good job! I don’t like to draw my gel-cell batteries below 11 volts no-load, so the 0% reading corresponding to 11.03 volts is perfect. A fully charged gel-cell measures about 13 volts no-load, so 13.04 volts for 100% is perfect. Looking at the three-cell Li-Ion pack graph, 9.34 volts at 0% corresponds to about 3.1 volts per cell. In my opinion, that’s right on. 12.47 volts corresponds to 4.16 volts per cell, which again, is right on! It’s important to note how the curves have different shapes – a lead-acid battery slowly tapers off, while the Lithium-Ion has a steep drop below 10%. Both match the discharge curve of the battery chemistries involved.The unit has a good bit of input filtering, taking some time to ramp up to 100% when first connected. This is a good thing, as it will ignore any sudden changes in voltage, preventing an unstable reading.In conclusion, this is an excellent product. It comes well packaged, I found it to be accurately described in the Amazon product description, and it works very well. I’ll definitely be buying more of these units in the future.

This is a quick and simple battery gauge that lets you know the state of your battery (or pack). Comes with two sets of self tapping screws (1 flat, 1 rounded), and is simple to wire in.For normal use, power up without pressing the button. Shows a battery bar (flashing battery on super low), with a percent usage. Button then toggles between percent and raw voltage read.One important note: When connected, the blue back-light shuts off after 10 seconds. The LCD and monitor however, continues to run until power is cut. This may be important for those debating using it for specific applications.Programming is simple: Hold the button down the first power-up (or to reprogram) and it starts by showing the current mode. You can then click the button to cycle between modes. Mode is a number (#) and a letter (P/C/F). For P (lead acid), the test is for 12V*#. For C(Lith)/F(Iron-Lith), the test is 5+(10*#). Disconnect when on the mode you want, and it remembers it.

This battery monitor is super easy to use. It comes set up for 12V by default. The packaging includes a QR code leading to a short 3 page manual. But it's easy - just hold down the button, apply power, and then select the code for your battery, disconnect power and then re-connect. Voila, you are done! For display, the percent is the default, but you can press the button to see voltage, although it will revert back to percentage if you disconnect it. If you are testing batteries below about 6V, such as a single lithium ion cell (code c1), then the backlight will not turn on. For all others, the backlight is nice and bright. For mounting, there are two kinds of screws, captured neatly in the black foam, which also cradles the sensitive electronics during shipping. Obviously, if you wire this unit into some equipment, then make sure to put it after the power switch, so that the backlight doesn't drain your battery. Fun fact, if you attach it to more than the expected voltage, it still reads 100%. I just decided not to try connecting this unit in reverse. Also, it's not waterproof.

Don’t get me wrong so far this thing works but my complaint is the size. I didn’t want a tv screen or expect it for the price however it’s about the size of a 9 volt battery and that is generous a battery may seriously be wider. Also the wires a very short and pull out easy. I have decent vision and I still have to get extremely close to read the thing. So I really don’t use it I just check my charge controller even tho I have to push a button first I still find it less of a hassle. I expected to be able to glance at it quickly just to get a reading but that’s not what happened.