Mark Rigby of Froetek UK knows how to deal with terminal problems in lead-acid battery formation.
Over the last few years most, if not all, of battery manufacturing has been automated. With investment in automatic machines and development in manufacturing processes and methods, much of the manual labour time has been reduced or even eliminated altogether. However, no matter how quickly you can make batteries there is always a bottleneck in the formation and charging areas.
Connecting the batteries/cells is time-consuming— especially batteries with screw-type terminals. Several years ago I was discussing a problem faced by a Scandinavian customer while he was parallel charging his batteries. Different charge currents were being encountered in the different strings, resulting in both overcharging and undercharging.
The customer had tried various methods to solve the problem, even adjusting the density of the acid, but he still had them. After two or three discussions the questions of the connectors came up. They had screw thread terminals and were using flexible cables with ring terminals on the end. These were bolted to the batteries to create the string, the usual practice. On receiving a sample connector from them, I instantly recognised the problem. These connectors had been in service for a long time, and although their batteries were sealed, various oxides and dirt had built upon the contact surfaces obviously creating resistances.
On checking his formation connectors the customer found connectors at varying ages and levels of contamination. This was obviously creating string imbalances. We decided to change all connectors and attention to the way they were manufactured so that they were all equally efficient. I soon realised that these problems were commonplace. That’s when I had the idea for connectors to plug into or onto screwed or threaded terminals. This would not only save time but would also use friction to help to clean the new style terminal pins. Obviously, an acidic atmosphere is detrimental to anything that is conductive. So the use of insulation shrouds helps with this problem.
A test was carried out, in a customer’s charging facility, where 48 cells were connected and disconnected using the conventional method, (connectors and screws) and the same with plug-in connectors. The conventional way took 45 minutes to connect and a similar amount of time to disconnect. The plug-in connectors took 4.5 minutes to connect and 2.5 minutes to disconnect. There is also potential for energy and time savings just by using good clean connectors.
These connectors have now been in operation with many large battery manufacturers for several years and have proved very successful. Perhaps I can help you with your systems?
Mark Rigby:mark@rigby55.fsnet.co.uk