I have a couple of the Noco jump packs. No affiliation, just a happy customer. In the car I have one of the small ones that will fit in the glove box, it is good for a small car. Also have the one that is the size of a shoe box in the truck, it has a flashlight, USB, and 12 volt cigarette lighter adapters. I haven't put it on anything that it would not start, even an old diesel tractor with the battery reading less than 2 volts which required the safety bypass on the jump box to be used because the battery was so low. I've never seen that old tractor start that fast. Will say that the higher end jump boxes are expensive but they can provide multiple starts on larger vehicles or equipment without needing to be recharged. I don't know how well it works in cold weather, colder than Florida anyway, but it has been well worth the $$ I spent on it.