Battery recondition "myth or fact"

The "reconditioning" effect is due to equalization of the charge in the 6 cell in series in a module. This occurs during the last part of each charging cycle as the fully charged cells dissipate excess charging current as heat while the not yet fully charged cells get a bit more charge.

In the car, the battery is never overcharged so equalization of weak cells does not occur.

JeffD

 

There are a lot of different threads around describing different approaches that you might think of as 'reconditioning' ranging from the addition of lost water to purely electrical approaches. The purely electrical approaches use various techniques, including a high-voltage charger across the entire series battery, or RC hobby chargers across one module at a time. Many of the RC chargers are more sophisticated and better regulated than you might think.

The replenishment of water is an easily understood reconditioning step that the car clearly isn't able to do on its own. The people who are actively researching that technique are putting their modules through several charge-discharge cycles after adding the water, and it seems plausible that it could be necessary to do so in order to bring old crystallized electrolyte back into solution, etc.

What most people are doing with a charger alone is more or less limited to trying to bring the battery into better balance. A battery that only charges and discharges through many cells in series will have an inherent problem where small differences in the cell capacity will result in ever-larger differences in charge state. A very slow, controlled overcharge can reverse some of that effect, but you wouldn't want to do it all the time, because for the longevity of the battery, the car usually tries to control state of charge within 40 to 80 percent.

As for why the car couldn't do that itself, a number of us (at least in Generation 1 cars) have indeed noticed that on rare occasions, the car departs from its 40 to 80 percent control scheme, brings the battery to 100% and holds it there for a while, then drains it back into the normal range.

-Chap

 

The concept is that as the battery module heats up during the normal charge/discharge activity, some water vapor is vented which leaves a higher electrolyte concentration, some of which eventually turns solid.