Recently I had the awesome task of replacing the battery in my 1974 BMW 3.0S. Being skeptical of the “maintenance-free” battery because of poor reports and the problem of checking one’s charging system, I thought that I might have to spring for the BMW replacement battery. However, I managed to come across an American replacement at a fraction of the cost, and with caps so as to check one’s charging system if a problem should arise.

This battery is manufactured by the McCarthy Corporation in Chicago and is available in most sizes to fit Bavaria and 3.0S. The warranty is a prorated 36 months, and the price ranges from $35 $50 depending on where you are. There is little modification necessary to install this battery other than to trim off some of the plastic support so as to allow the battery clip plate to hold down the battery. Many dealerships in the Chicago area are finding out about these batteries and are stocking them.

Author: Hugh W. Whipple