I bought one of these portable jump starters. This one says in specification that it can start a big 6L gasoline engine up to 12 times on a single charge. Simple math implies that each jump-start attempt should consume 100%/12=8.5%. At least for big engines.
Now I am using it to jumpstart Chevrolet Aveo with a smaller 1.6L engine. I have tried to jump start my car with it like 10 times for 3-4 seconds each time and the portable jumpstarter's charge status has barely dropped from 74% to 72%.
This has left me wondering on how many WHr typically are needed to jump start a small 1.6L engine?
While I see that starter spins the belt in my car, is there a chance that actual load (e.g. camshaft) is somehow not connected to the belt and hence the charge on the portable jump starter drops by insignificant amount? By the way I am not able to start the car and I am also getting code "P0340: Camshaft position sensor error". See this question for more context.