Today, the specification of batteries in buses is a balance between high power drain under a short time period when the engine starts, and cycling performance with electrical loads connected when the engine is not running.
There has been a steady growth of electrical consumers on buses, which are active even when the engine is not running - and therefore not charging - causing the batteries to drain. As a consequence this leads to a slow degradation of battery performance and without auxiliary charging they can eventually become completely drained.
Volvo has been working to address this issue and as a result can now offer a practical solution with the introduction of the I Start system.
From Week 41, customers can order the new Volvo I Start system, which includes a separate set of batteries dedicated to engine start, as an option on the B9TL.
The main features of the Volvo I Start battery system are:
• Secure engine cranking by using a dedicated set of batteries to crank and a separate set for consumers
• Improved battery reliability
• Optimization of each set of batteries
– Low internal resistance and high power for cranking
– High cycling features for consumer batteries
• Optimum battery weight and volume
• Reduction of cabling between starting batteries and starter motor
Ian Downie, Volvo Bus Product Director commented, "Whole life vehicle costs are an important consideration for our customers. The ability of the vehicle to start first time before entering service, even after the lights may have been left on, is an important factor in the operators cost structure. By introducing this clever solution, this issue is prevented, whilst having no detrimental affect on vehicle weight."