Jen-in-Wellies

I actually do have a Victron BMV. Unfortunately, when it was made, Bluetooth was a long time in the future, so one of these voltage gadgets was just the thing and a considerable saving over a new BMV. The ancient BMV did have it's configuration set up the same as the new models for Lithium batteries.

Is this inverter on a boat? What is usually used to charge the batteries? Are you based in Greece? A typical lab power supply is going to need mains to run. How are you planning to get that mains without an inverter? A 5A lab supply will only produce 70W at 12V, so won't be an adequate test for an inverter. Most inverter problems on the forum actually turn out to be either battery problems, or wiring problems. The inverter merely shows up the fault in something else, due to it's high demand for current.

I installed one of these gadgets. https://www.victronenergy.com/meters-and-sensors/smart-battery-sense Connects across the battery terminals and can send battery voltage and temperature via Bluetooth to Victron MPPT and Orion B2B chargers. I was seeing small differences in the voltage reported by different charging gadgets, depending on current flowing, path length and wire size. Now they all know what is going on at the Lithium battery end. Cheaper than a Cerbro and easier to set up with a non Victron battery.

The trick is to keep the tank close to full, or empty, whichever wastes the least current!

It is no surprise that James Brindley held a patent for "A wheeled container on castors, made of wire and with handles to enable it to be pushed. For the conveyance of pre-purchase items in a shop, or other emporium." The 18th century canal boom would not have been possible without this other invention. 😀

I am guessing, to be in proportion, you'll find dumper trucks in the mud at the bottom, instead of shopping trolleys.

I used a YFS201B flow sensor in my system. Still working well and accurately five years later. Right now it says there is 12 to 16% left in the tank, so I will need to break out the hose pipe soon.