After observing battery voltage gauge on my car, I can see my lead acid battery operate voltage is from 11.8v to 14.8v.
The car is about 5 years old, and while start/stop, the car drains the lead acid battery, and voltage drops from 14.8v immediately to 12v and when it drops to ~12.2v, the engine ignites again. the stop won't last more than 30 seconds, which is annoying.
Now I would like to have a new battery that prolongs the start/stop time.
I intend to use Panasonic NCR18650B Batteries. 3 in series many in parallel. lithium ion packs with BMS battery management system.
But charging will easily pass 4.2v for each cell. 14.8/3=4.93v, when discharging, batteries is ok: 11.8/3=3.93v.
If I use 4 in series, 14.8/4 = 3.7v and 11.8/4 = 2.95v. And batteries will only be partially charged to 3.6~3.7v, which is another problem. and might get over discharged.
Any suggestion for me to use these NCR18650B to replace the traditional car batteries?