NOTE: If you are using a really nice BMS that has active balancing, you can get away with putting healthy, fresh cells in a tired battery pack. This is because such BMS are able to correct the imbalance fast enough. There is still reduced capacity, but not nearly as much as there would be in a battery pack with a lower-end BMS. However be very careful doing this you do not want to put new cells with old cells that are too far apart in true capacity.
Most vehicle batteries last four to five years, but you should have it examined at every oil change — whenever your hood is opened. At that time, your Computerized AutoPro technician will inspect your battery’s terminals for corrosion and cleanliness.

If you have Magnesium sulfate (commonly known as Epsom salt) with you can easily recondition a car battery. First step is to check the battery voltage and ensure it to be less than 12 V. This shows that it is already dead. Heat about half a liter of distilled water to about 333K-348K (about 30 K below the boiling point of the water) Now, mix about a quarter of Epsom Salt in heated distilled water and stir it until the salt dissolves. For two different types of cells, this step involves different procedures.For flooded cells, you need to remove the battery cell cap.For dry cells, please drill through the sealed cap.For both the cells, pour out the old electrolyte. Insert the new electrolyte into the cell with the help of a funnel. (mainly Epsom salt + water) Next, for a flooded cell, replace the battery cap. For a sealed cell battery, plug the hole in this step. Keep in mind that you have to keep electrolyte properly distributed with no hint of air bubbles inside the cell. Finally, charge it slowly by keeping it on trickle charge overnight and then let it cool. By morning, you have a reformed cell in your hand that performs as good as new!
If your iPhone feels sluggish, you might be in line for iPhone 6 battery replacement. One of the more obvious signs you need a battery replacement involves an overgrown battery. In this case, your battery has swollen up to the point that your phone has broken open. While the other signs are less obvious, this one will be sure to draw concern. If your iPhone’s battery has overgrown, be sure not to puncture the pack.