Nav-Aid Battery Bank

Navigation aids are obliged to work, and the obligation does not pause when the platform does. If a structure marks itself with lanterns, a fog signal and a racon, those aids have to keep operating through a power failure, a shutdown or the period between a generator tripping and someone attending. The battery bank is what provides that, and on an unmanned structure it is the difference between a marked obstruction and an unmarked one.

Sizing it is arithmetic rather than judgement, which is worth insisting on because a battery bank chosen by rule of thumb is either an expensive over-purchase or a shortfall nobody discovers until it matters. The calculation starts with the connected load - each lantern at its night intensity and flash character, the fog signal at its expected duty, the racon, the control panel - and multiplies it by the required autonomy, which is set by the applicable recommendation and by how long it realistically takes to attend the structure. From there come the recharge current, the charger rating and the physical size and weight of the bank, which then has to fit somewhere and be supported by the structure.

Two factors distort the result and are regularly missed. Temperature matters: battery capacity falls at low temperature and life shortens at high temperature, and a battery enclosure on a sunlit deck in Indonesia is a hot place. And the depth of discharge assumed in the calculation determines how many cycles the bank survives - a design that routinely takes the batteries deep will need replacing years earlier than one that does not. Whether the enclosure sits in a classified area also determines what may be installed, since batteries generate hydrogen on charge and their housing and ventilation have to account for it.

MSM Offshore supply these within complete turnkey NAVAIDs systems for potentially explosive environments, designed according to IALA G-1162 and ICAO Annex 14 recommendations, with ATEX and IECEx Category 2 and Category 3 certification across their equipment range, and they supervise installations. We size the bank against your actual aid schedule and required autonomy and confirm the capacity, the chemistry and the enclosure at quotation - there is no standard answer to quote here, and a figure given without the load schedule would be guesswork.