Not sure what you mean by this.... I don't think I have any fans or a 4T...I especially dig the fans for the 4T cooling application.
These are the rechargables I am using for my prototype. The final ones will also be rechargable NiMh, but of a better quality. I have decided on Eneloop XX Batteries for the actual units. They are top dog as far as rechargable batteries go.
The reg/rect I just got installed will charge these battery cells great!
Should work out!