I took it for special occasions on the road: the UAZ battery, on a snowmobile, sits down in the cold. And I applied it unexpectedly near the house :) After Webasto work, the battery on the Toyota LC200 (engine size 4.7 l, gasoline) was discharged. Only two of the four LEDs on the booster were lit. This was enough to start the engine with ease in frost - 23 degrees. The case is not extreme, of course, but encouraging.