Thanks for the feedback guys.
I understood that the resistance value needed to be changed to change the current limit value. Thanks for clearing that up for me Crutschow. I was planning on optically isolating the micro controller from the rest of the circuit for protection anyways. I want to be able to sense the current as well, so I will implement the sparkfun circuit into the rest of the circuit as well. But this is all just research at this stage. I am planning to build a SLA smart batter charger. I've posted previously about another design in a different thread that made use of a opamp configured as a differential amplifier to initiate charge and to stop it, but the circuit is not a very good circuit. I want to implement a three stage charging protocol with this project. But as I said it is only research at this stage. Thank you again for the information, I might be asking about it again in the future when I start to implement these circuits.