Yunsailing 2 Pcs High Precision Watt Meter Power Analyzer Battery Consumption Performance Monitor with Backlight Digital LCD Screen(9000)

I bought these not knowing what to expect. I was pleasantly surprised to get them and discover that they worked great with 12VDC power systems to show current load, voltage, and consumption -- as advertised. I use them to keep an eye on DC battery performance in a battery system so I know when to charge the batteries. I also use one with a 12VDC power supply to monitor power consumption of some radio gear. They worked out great.

I felt compelled to write a review because there wasn't one at the time I purchased this pair of analyzers. I saw on Amazon that there were several analyzers like these for sale by various sellers and they all looked alike to me - the main difference being whether you needed/wanted 150 A or 200 A limit. I wanted one to connect to solar panels to monitor energy production and troubleshoot low/zero-producing microinverters, and decided on this pair of analyzers because, at least at the time, it had the best unit price ($21.99 for two) - furthermore, having a second one is nice for comparing solar panels. Firstly, be aware that they do not come with any connectors, just 6-cm long cables sticking out, with 4 mm of each end stripped off. One reason for my not rating these analyzers 5-stars is because it was not easy attaching mc4 connectors to them. Let me emphasize that from the info/reviews of the other analyzers like these, their cables were all only 6-cm long. Therefore, this criticism would apply to all of them except the considerably more expensive analyzer that already had mc4's connected to it. I would like for the cables to either have been 8-cm long or stiffer. Luckily though, I discoverable my Craftsman 1/8", 6" long screwdriver could be slid in behind the metal terminal of the mc4 to snap it in place without a lot of trouble. Next, the analyzer can run off the solar panel energy without an auxiliary battery as long as the solar panel voltage does not go below about 4.8 V. Once it does, the analyzer stops (fully) functioning. (Something will still appear on the screen until there's no voltage at all, but it is not what should appear.) This leads to my other reason why I am not rating these analyzers (and, maybe all the others being sold as well) 5-stars: they don't come back to "life" once the source voltage (from the solar panels) increases to about 4.8 V. I found that I had to disconnect them, wait for the analyzer to fully shut off, and then reconnect them. Well, the better alternative was to use an auxiliary battery, for which there is a connection on its side (with polarity symbols on the back of the analyzer). Finding what to buy was a challenge. I think I checked all the analyzers like these being sold, with only one of them saying from what site to go to buy their connectors with wires connected - but without a battery holder. I was going to buy these connectors with wires only, but thought I should first check on battery holders. This is when I found: "4 Cell AA Battery Holder W/JR Style Connector Receiver Battery Pack - 5 Pack - Apex RC Products #2931" Its URL is: https://www.amazon.com/dp/B01NAN66N8 Since it was so inexpensive (a 5 pack for only $9.99) and "Free Returns", I purchased them to try, and found that if I slightly bent the three pins on the analyzer inwards, I could slide on the "JR Style Connector", and it works! - in fact, I've been using the auxiliary battery pack for a couple of weeks now, and it has been working properly. Lastly, I want to share that, even though they are not waterproof, during the couple of weeks I have been using one of them, it has rained, but it has not failed. It is mostly shielded from rain by the solar panel, but nonetheless, what happened one day was that condensation formed on the lower, left side of the inside of the clear plastic covering the screen, making it difficult to read what was under the condensation, but, after the weather cleared that day, so did the screen.

Great for the price paid. Not to be used to calibrate anything. However, an outstand way to monitor battery data in real time. I just need to be in the ballpark of power going out and power coming in when using solar. I don't need 100% accuracy. Perfect for my application.

I ordered 4 of these, and 3 out of the 4 started doing the "blank screen of death" (see pic) after a few days. This glitch occurs whenever the voltage goes from 0 and creeps up gradually, which means EVERY MORNING when the sun comes up on my solar panels. The only way to get them out of this "blank screen" state is to cut power, and turn it back on suddenly when the voltage is high enough (~20V or more) to get them going. I have a disconnect switch on my solar panels, so I had to do this EVERY DAY when the sun was up high enough to re-start these Ps O S. It got tiresome and will eventually wear out the switch, so I'm just tossing these in the trash where they belong. These meters are a knockoff of the ridiculously overpriced ones from PowerWerx. I bit the bullet and ordered those (which cost literally 4x as much) but they perform as intended with no issues so far after about 3 weeks.

Add some MC4 connectors and attached it to my solar panels and battery, worked like a charm. Clear and easy to read display, well made, plus they give you an extra one! :-)