Alex Brown, Technical Director of Ashleigh Engineering Services is set to start building InnerTuba’s on board renewable energy systems – integrating dynamo hubs with photovoltaic solar panels.

We will begin the build stage of  Alex’s impressively detailed design next week.  The technically minded might enjoy reading his specification ….

‘Following our conversation on Thursday last week I would like to confirm our considerations for your renewable system.

1. To employ 2 x 24V Li-ion electric bicycle batteries with built in BMS and a mains charger (in the event of total power loss). The capacity of these would be dependent on final load requirements / charge capability. One battery would supply trike control power as the other charges, selected via switch. The batteries would also be removable.

2. Each renewable source (eg each dynamo, PV array etc…) would have its own SEPIC PCB designed by us to provide a suitable charge voltage of around 25.2V. These would be connected together to feed a current control circuit which would supply the battery under charge. The current control circuit would also feature a handlebar control to allow the amount of charge current (and inherently pedal load) to be adjusted. The individual SEPICS would remove the need for MTTP circuits.

3. Outputs to various equipment would be controlled using high efficiency DC-DC buck converters. These outputs would include a Laptop output and several USB charge outputs. An AA battery charger would also be included.’

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