If you have a life mode on the charger then use it. I would not charge the life battery any other way. In the starter box you can use 2 2s batteries just make a harness to get the voltage up to 14.8. The lead battery, like above charge at 2-4 amps. It will take awhe to charge and I wouldn't use it personally but it will work. If you have more questions about connectors post a picture.