S Jones Containers gives Traffic Group Signals green light with new battery charging solution

Container conversion specialist S Jones Containers has designed and delivered a bespoke battery charging solution for Traffic Group Signals, a manufacturer of traffic management systems, to provide a safe space to charge its lead acid batteries at its new site. 

Traffic Group Signals wanted to incorporate a lead acid battery charging facility within its new building to house the VRLA (Valve-Regulated Lead-Acid) batteries which power its traffic light units. However, due to the potential risk of fire and explosion of hydrogen gas during the charging process it wasn’t possible to secure appropriate building insurance. The team therefore tasked S Jones Conversions with creating a specialist containerised storage and charging solution which could be located well away from the main building, would contain any fire, and provide adequate access for emergency services.  

The knowledgeable team of design engineers at S Jones Conversions Division worked closely with Traffic Group Signals to devise a tailored solution to meet all the requirements, with safety being the main priority. Using an ISO 20ft high cube side opening shipping container as the basis, the unit was converted by S Jones’ skilled team at its dedicated workshop. A fire alarm system was installed with relay links to a contactor safety circuit to turn power to the battery compartment off in the event of an alarm or depression of a manual e-stop and its patented Contain-a-Lock was installed for extra security.

The first step was to divide the container into two compartments, separated by a fire rated ‘L’ shaped bulkhead gas sealed at atmospheric pressure. These compartments provide a small area to house standard charging equipment plus a larger separate compartment with bespoke racking designed to hold up to 48 12v VRLA batteries. The racking also included dummy DC charging connectors to secure the charging cables and keep them clear of each shelf location while being loaded into the unit by forklift truck. 

All works were completed within the guidelines outlined by BS EN IEC 62485-2: 2018 Safety Requirements for Secondary Batteries and Battery Installation. As part of this, the team calculated the maximum possible emission rates of hydrogen gas by assuming the worst possible scenario with maximum current charging all 48 standard 12v lead acid batteries at the same time. Using these projected hydrogen emission calculations the team created a ventilation system using an ATEX Zone 1 lighting and ATEX Zone 1 fan forced air solution. An additional safety factor fan was also incorporated into the ventilation design to ensure that concentrations of hydrogen in air within the container battery compartment would never reach their explosion limit even if one of the two installed ATEX fans failed. Power to the ATEX fan ventilation circuits is designed to switch on automatically and run continually when any one of the 48 battery chargers is switched on. 

Andrew Nicholls, Head of Conversions at S Jones Containers said: “As with every project we undertake, every detail here was carefully considered by our in-house design engineers to make sure the unit perfectly met the criteria from a safety and usability perspective. The fact that that fire alarm was fully connected to the customer’s existing battery management system enabled remote monitoring while the positioning of the DC cables was such that in the event of forklift truck damage to an individual cable, it could be quickly replaced to minimise plant downtime. We pride ourselves on providing a solution that goes beyond meeting regulations and which ticks all the boxes for our customers.”

Mark Hutchinson, Director at The Traffic Group commented: “The design and construction of a bespoke battery charging facility was new ground for Traffic Group Signals. S Jones provided us with advice on the design and technical aspects of our proposed unit, having listened to our original requirements. They guided us through the options available to us, to arrive at a design that not only fulfilled our needs but complied to all the relevant safety standards. They involved us throughout the process and completed the unit to the agreed schedule.” 

For more information about battery storage and testing solutions at S Jones Conversions, please visit: https://www.sjonescontainers.co.uk/container-conversions/plant-room/battery-storage/