Hello all! I'm new and ready to learn.
I have a small open wheeled formula car that has a 12v battery on-board (260 Cold Cranking Amps, ~18ish Amp Hours) to run the starter(best guess, less than 30A), two electric fans (6A each), and one electric water pump (1.5A).
I also have a large car battery that I use when the car is off to run the on-board fans and water pump. This plugs into the car though the same charging port for the on-board battery (so the batteries in parallel). When I race, the repeated starting and running the fans + pump will cause the battery to drain before I'm done. It gets put onto a charger before every race. Race day usually find me running the fans and pumps for about 2 hours total and 6 to 12 starts.
here is the question: If i switch to a lithium battery, how do i keep the big booster battery (a regular lead acid car battery) from trying to charge the lithium battery? (I know that Lithium batteries have to be charged at a certain rate.) Do I not even need to worry about it? Is there a diode big enough to keep the battery from charging? Educate me! (a higher capacity on board battery is kind of an option - it add weight (bad) and there really isn't one big enough in my price range to run everything for as long as i need.)
Brad.
I have a small open wheeled formula car that has a 12v battery on-board (260 Cold Cranking Amps, ~18ish Amp Hours) to run the starter(best guess, less than 30A), two electric fans (6A each), and one electric water pump (1.5A).
I also have a large car battery that I use when the car is off to run the on-board fans and water pump. This plugs into the car though the same charging port for the on-board battery (so the batteries in parallel). When I race, the repeated starting and running the fans + pump will cause the battery to drain before I'm done. It gets put onto a charger before every race. Race day usually find me running the fans and pumps for about 2 hours total and 6 to 12 starts.
here is the question: If i switch to a lithium battery, how do i keep the big booster battery (a regular lead acid car battery) from trying to charge the lithium battery? (I know that Lithium batteries have to be charged at a certain rate.) Do I not even need to worry about it? Is there a diode big enough to keep the battery from charging? Educate me! (a higher capacity on board battery is kind of an option - it add weight (bad) and there really isn't one big enough in my price range to run everything for as long as i need.)
Brad.