Best regulated 12V battey pack design

[eKretz]

Ok, here's the deal. I have several 18650 li-ion batteries reclaimed from an old laptop battery. I also have a dead battery pack from my camera that needs replaced. I want to make a pack with the li-ion batts to use in the camera as a project. What is the best type of circuit to use that will waste the least amount of battery power? I have a decent amount of spare parts, including some 7812 reg's, but if there is a better way to go, I'd love to hear about it, or if you have any good ideas for me to try out or links to read.

 

[davenn]

hi there

before you think about what you are going to power with the reclaimed batteries,
have you thought about how you are going to charge them.?
Lithium type batteries require very specific charging systems

Dave

 

[eKretz]

Yes, I recharge them in parallel with my bench supply, been doing it for years. I shunt the output to set current limit at .5-1C (no preview function on my supply) and then set voltage to 4.15V. The supply charges CC until the current drops below the limit, then switches to CV and tapers current down. I shut off at .1-.2A. It's worked great for a couple years now.