Charger for jump starter

Nope. Most cell phone chargers put out around 5.0 volts, and they usually use a different type of plug. The first thing I'd look for is a charger for an older cordless phone They typical developed over 12 volts to run the base unit. You can also look at some chargers for older laptop computers. Those commonly developed 19 volts. Your battery pack has regulating circuitry inside, so it will tolerate the higher voltage.

The next item is the plug style. The most common for battery packs is a small round plug, about a half inch long, with a hole in the middle. Once you find that, you also have to look at the polarity. If you aren't sure of that, just plug it in and try it. Most battery packs have some type of light that turns on to tell you it's charging. If your charger is of the wrong polarity, no damage will occur, but don't leave it plugged in as it could overheat after a while.

I have two battery packs, and both have a symbol next to the charging jack to show the correct polarity. Today most chargers have the same symbol. If the two symbols are the same, the polarity is correct. This drawing shows the symbol. It's the location of the plus and minus signs that are important.

Does the plug match? Did you look at the polarity symbols? Did you try it?

Should be fine. The battery pack watches the internal battery's voltage to determine when to stop charging it. That isn't affected by the charger's voltage.