Review on 🔋 DROK Voltage Amp Meter DC: Monitor Solar System Power with 0-300V 200A Capacity - Hall Sensor Voltmeter Ammeter Current Detector Panel by Nathan Issa

I purchased this item to monitor my solar lithium battery in my RV. This gauge is inexpensive, easy to install and seems to work. The first light I had had display issues after about 6 months. Some segments of the LCD remained on and the information on the display could not be read. Drok sent a replacement straight away and the replacement works fine for another 6 months after that. I found that this instrument is not accurate. I suspect the reason is that it uses a hall sensor to measure the current. A Hall sensor is a small coil of wire that measures the magnetic field around a wire, where the field is proportional to the current flowing through the wire. Current clamps work the same way and are a convenient way to measure current without breaking the circuit. While the Hall effect works well for measuring current, it has difficulty measuring very small currents due to interference from nearby electrical wires. In my case, current measurements are often as low as 0.2 or 0.3 amps. With a resolution of only 0.1A, this sensor is at its most inaccurate when measuring low currents like this. Drok's current measurement has an accuracy of about 0.1A. I know this because my solar charge controller also measures current and the two numbers match within 0.1A, but the smallest step it can measure is 0.2 A. If the current is 0.2A and I turn on the lamp at 100mA, the reading will alternate between 0.2 and 0.4, like it's trying to read 0.3A, but somehow trying to get the right one value within 0.1A. It simply shows the accuracy of the ADC (Analog to Digital Converter) which is clearly limited. To measure capacity, the Drok meter combines current measurements over time to calculate power consumption and battery capacity. But if every (weak current) measurement has large errors, these errors will accumulate and lead to very inaccurate results over time. Drok has a wide range of "residual capacity" when switched off, from 15 to 25 Ah when not in use. If you don't fully charge and go through several partial charge/discharge cycles, the Drok will continue to move away, indicating the capacity will drop below zero, before finally shutting down. Different discharge scenarios can vary by up to 30%. Then the Drok will reach 100% when charging from the outlet long before the battery is fully charged. It remains at 100% while an additional 10 to 20 Ah is added to the battery. I have noticed a capacity change of up to 20% when charging. Gorse will automatically reset to full when it reaches 100% and will be more accurate from there. However, if you can't charge to 100% (e.g. there isn't enough sun on a cloudy day to get a full charge) and you run multiple cycles in a partially discharged state, the accuracy will degrade. Anyway, this device is inexpensive and got me going with a workable solution, but in the end I couldn't rely on it to tell me when my battery was low, so I gave up this device and bought it a new more expensive shunt-based meter. I will post a review of this new counter once I have it installed. EDIT: I installed a new battery meter similar to DNEX's for about $75 that uses a 100 amp shunt. I've found the shunt based gauge to be MUCH more accurate. Running them side by side I now see that the drok meter is bad because its current readings are extremely inaccurate. My new meter measures up to 0.01A. I checked both gauges for a few charge cycles and the new gauge was fine, but Drok was clearly wrong and got worse over time.