Figure out what kind of battery it is that you have, i.e. chemistry type and capacity and then choose the appropriate charger.  To do this look at the labeling on the battery that you have.
 
Chemistry
1) Be sure to choose the "lithium" option if your battery says lithium-ion
2) Be sure to choose the "LiFePo4" if your battery indicates that
 
Capacity
Here is the math:  If your battery is 1ah and the charger is 1amp then you battery will charge within 1 hour; second example, if your battery is a 10ah and you have a 1amp charger, your battery will take up to 10 hours to recharge depending on how much it has been depleted.  A 2amp charger will charge a 10ah battery in 5 hours.
 
note: a 10ah battery will charge within 10hours if you are using a 1amp charger, and in half that time with a 2ah charger; so you may choose either for the 10ah batteries specifically.
 
Choose 1amp versions for any battery up to 10ah capacity
Choose 2amp versions for any battery from 10ah or above
 
Please call us if you are still unclear on this: 1-855-784-3474 (Operating on Pacific Time)