But I would want to have fully able back-up in the case some mistake was made and my house batteries did become virtually depleted. Granted, using a totally depleted rather small gel-cell as the dummy battery is a worse-case rather extreme scenario. Battery #1 started the engine in 1-2 seconds. Reconnected the dedicated G27 batteries.

Just in case the pocket starter needed some less resistance between its clamps and the starter, I even ran a second starter motor wire. Upon turning the start key, the starter did engage, but could not crank the engine. Connected the pocket jump starter as per the instructions. Connected in their place the same gel-cell I used as the simulated dead battery in the car start experiment. Disconnected my group 27 deep cycle #1 and #2 batteries from the circuit.

Essentially the same process as the car. I disconnected the pocket jumper and went about re-charging it again. The engine started almost as quickly as with it's normal fully charged 12V battery. I then connected the pocket jumper per the instructions. I then turned on the lights, heater, etc to drain the battery until the all car's systems were totally dead. I disconnected the 12V+ harness from my Toyota's battery and connected the gel cell as it's substitute. I have an old 12ah 12v gel-cell at home which I occasionally use as a 12v power supply. Charged the pocket charger per instructions until it's LED's showed fully charged. However I thought to at least post my experience that maybe not all of these units have enough oomph to turn over every sailboat diesel engine in a severely depleted battery situation. Because it capably did what was specified (start a car) I don't want to degrade the product name by mentioning it. And it did easily start my 1.5 liter Toyota in the same dead battery test. The product itself looks very well designed and made. The unit I bought totally failed to turn over my Yanmar 2QM20 in my simulated dead battery test. The thread prompted me to take advantage of a Black Friday weekend offering at a well-known brick-and-mortar boater's supply store. I had first noticed these about a year ago. On this forum several days ago was a thread about pocket jump starters.

Pocket jump starters