answered 4 years, 8 months ago
Yes and no. Okay so I quick lesson in booster packs.
If a booster pack has an ON/OFF switch, it will "put out power" when in the ON position. These products have "reverse polarity warning" meaning they indicate when you've got the connection reversed BUT, if you turn the switch ON, you will still get power and can cause some fireworks.
Other units that don't have an ON/OFF switch have a built-in sensor that must sense voltage (somewhere in the 3-5V range) before it will send power to the clamps. Consider this "reverse connection protection" because you can't blow yourself up. It simply won't put out power unless it senses the minimum voltage.
So back to your question. If you've got a totally dead battery, a booster pack with a mininum voltage sensor won't do anything for you. BUT I also won't say that one with an ON/OFF switch will either. Yes, they will send power but depending on how big your engine is, how cold it is and a bunch of other factors, the booster may not have enough power to turn the engine over. Keep in mind, your car battery is completely dead so you're relying totally on the booster pack's battery which is a fraction of the size of your car battery.
So the point is, if you want a product that will at least attempt to start a dead battey then look for a model with an ON/OFF switch. If you want to improve your chances that it will actually work for you, look for one with the biggest internal battery. This Nautilus one has an ON/OFF switch and also has the largest battery of any booster pack offered at Canadian Tire at 33Ah.
By the way, the premise behind the minimum voltage approach is that even a completely discharged battery still has at least 9+ volts in it. If a battery has 0 volts, it's broke (short, dead cell, sulphation, etc.) and most booster packs out there may not have enough power to start your engine just on the power of the booster pack battery.