Hi, I have built a large, lithium ion battery bank, so that I may power some of my projects from battery. The bank is 10,000 milliamp hours at 16.9 volts, and was wondering the following. Can I charge my 16.9 volt battery pack with a 12 volt dc source? would It decrease the efficiency? Would my battery pack only charge up to 12 volts? Thank you all for your help! it is much appreciated!