Most battery packs for portable devices are specific to the manufacturer

Most manufacturers of cell phones, laptops and cameras develop their own battery packs. A model change often results in a redesigned battery. The typical contact arrangements of cell phone and video camera batteries are: battery positive, negative and temperature sensor. Additional contacts may serve as control switch or battery type identifier. “Smart” batteries have extra contacts to provide state-of-charge indication and other information. Recall that there are no norms and standards for these batteries. Each manufacturer has its own design (see Battery Giant December blog posts.)

In the 1990s, however, the Smart Battery System (SBS) forum made a concerted effort to standardize on battery norms for laptops, survey equipment and medical instruments. Beside physical size, these batteries ran on a standard SMBus protocol. With miniaturizing and securing a lucrative battery replacement market, laptop manufacturers went their own way. The SMBus batteries are still widely used today for specialty instruments.

Recall that the typical battery has the inherit problem of not being able to communicate with the user, as neither weight, color, nor size provides an indication of the battery’s state-of-charge (SoC) and state-of-health (SoH). The user is at the mercy of the battery. Today’s rechargeable “smart” batteries, however, are equipped with a microchip, and able to communicate with both the charger and user.

There are several types of “smart” batteries, each offering different complexities and costs. We have determined that the SMBus is the most complete of all of these smart battery systems. It represents a large effort from the electronics industry to standardize on one communications protocol and one set of data. The Duracell/Intel SBS, which is in use today, was standardized in 1993. It is a two-wire interface system consisting of separate lines for the data and clock. The objective behind the SMBus battery is to remove the charge control from the charger and assign it to the battery. With a true SMBus system, the battery becomes the master and the charger is a servant that must follow the dictates of the battery.

As with life, it’s all about having the most qualified person in charge!

For additional information, visit www.batterygiant.com