About us

African Petrochemicals is South Africa’s leading quarterly print and digital trade magazine for the past 15 years. Featuring all the latest petrochemical industry news, special reports, technological advances and much more.


Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages

Stationary* Battery Basics: Jars & Straps

There is so much terminology related to stationary batteries and it’s hard to know what everything means. So, what’s the difference is between jars and straps?

What is a jar?
A stationary battery jar is the container that holds the cell or group of cells and electrolyte. It is also commonly referred to as a battery case or cell case. Jars are typically made out of some kind of thermoplastic substance. However, hard rubber is sometimes used as well. If the battery contains nickel-cadmium cells, the jar may even be made out of steel. Vented lead-acid batteries normally have transparent jars to allow for plate and sediment inspection.

What is a strap?
A stationary battery strap is the component in a cell that joins plates of like polarity in parallel.  It is an electrical conductor that is made of copper. It typically has a lead or tin plating for lead-acid cells. Nickel-cadmium cells require a different connector. They are typically made with nickel-, cadmium-, or tin-plated copper, or even steel bar.  Occasionally, the strap may be insulated copper wire or lead (with or without a copper insert) for lead-acid batteries, depending on the manufacturer’s specifications.

*Stationary batteries

Transportation batteries function as start/stop batteries. The primary discharge occurs when the vehicle is started. After that, it spends the rest of the drive time recharging.  Motive power batteries do not operate this way. Instead of only being used to start the machinery, there is a continual discharge. Stationary batteries are used constantly while in operation and used until depleted, or until the job is done, and then recharged after use.

Midtronics electrical system testing technology is used by six major automotive manufacturing facilities in South Africa in on-vehicle equipment, recording events that may lead to battery or electrical system failure. In addition to this, two leading South African battery manufacturers and distributors have committed to using the Midtronics technology in their facilities and distribution outlets.

Comtest is Midtronics accredited partner in southern Africa.  For more information on Midtronics battery technology, or for seminars, demos or to locate the nearest dealer, contact The Comtest Group on 010 595 1821 email:



Leave a Reply

Your email address will not be published. Required fields are marked *

Website Protected by Spam Master