Review on DC Multifunction Battery Monitor Meter, LCD Display 0-200V & 0-100A, 🔋 Ideal for 12V/24V/48V RV/Car Battery - Digital Solar Power Meter, Multimeter Ammeter Voltmeter by Mike Starling

This is definitely not a Victron. But Victron costs at least $200 while this is less than $20. SOC (State of Charge Meter) is a good bar graph and also shows the current voltage, current, power and energy. This will give you a good idea of the condition of your battery system. During installation, you must set the full voltage for your system and the cut-off voltage. I used 12.9v and 10.8v. When I first set it up I accidentally set it to 212.9v and 110.8v because the hundreds digit is cut off on the display. It was confusing, but I finally found the problem. Lead-acid batteries have one useful property. Whether flooded, AGM or gelled, battery voltage drops in proportion to the amount of energy remaining in the battery. A fully charged "12V" lead-acid battery will measure approximately 12.8V and a fully discharged lead-acid battery will measure approximately 11.8V when the battery is idle and not connected to a load. So if you measure 12.3V you can say the battery is 50% dead. Batteries have a certain internal resistance, so they measure slightly less under load. The SOC meter works with this calculation. This method makes it easy to determine how much energy is left in the battery. With lithium batteries, the situation is not so simple. They deliver almost the same voltage whether they are 80% full or empty. Towards the end of their cycle, they lose tension very quickly. In order to calculate the energy remaining in a lithium battery, it is necessary to constantly monitor the battery and keep a current count of the total energy drawn. The state of charge measurement in this device is voltage-based and therefore only useful for lead-acid batteries, not for lithium. The other measurements provided are still useful and nothing will break when used with lithium batteries, but the SOC bar graph is for lead-acid batteries only. The instructions are translated from Chinese and are not particularly helpful. The biggest issue for me is that the backlight stays on when the device is monitoring. You can put it to sleep, but then no data will be collected. Some people built them into closets so the backlight would be less annoying at night. I turned a problem into a blessing. My batteries are mounted under the entry steps, so my batteries could easily be installed next to the steps. The backlight illuminates the steps at night and does not hit directly in the eyes when sleeping.