Dave “Battman” attempts to help a customer solve a battery charging problem:
I received your battery yesterday from UPS and noted that the open circuit voltage was 11.2 volts. This is important becauseit tells me that this particular battery is probably “good” but just 100% electrically discharged.
 
A “good” fully charged battery has an open circuit voltage [...]

A very good customer of ours called me today to discuss buying a new battery for his 1100cc BMW motorcycle. Five years ago he bought a Panasonic battery from us for this same BMW motorcycle and it was still working but he was occasionally experiencing some difficulty starting the bike.
He wanted a battery with higher [...]

Now we all know that there is a time that the battery in your device will have gone through enough charge/discharge cycles that it decides to not play anymore and you need to replace it. There are ways you can tell that your battery just won’t last much longer. Such as when the device lasts [...]

Although many people know how to do this, we do get this question from time to time. In order to set up a “series” of batteries, the positive terminal of the first battery is connected to the negative terminal of the second battery; the positive terminal of the second is connected to the negative of [...]

WARNING-BATTERIES PRODUCE EXPLOSIVE GASES
These instructions are designed to minimize the explosion hazard. Keep sparks, flames and cigarettes away from batteries at all times. Both batteries should be of the same voltage (6, 12, etc.).
SAFE BOOSTER CABLE OPERATION
When jump starting a car, truck or any other vehicle battery, always wear proper eye protection and never lean [...]