VICTRON ORION 24/12V/5A DC-DC-Konverter

Because most low-voltage equipment is designed for 12 Volts,
Victron Energy supplies DC/DC converters which deliver a stable 12 Volt
supply from a 24 Volt system.
These products are also distinguished by high efficiency, together
with absolute safety. An inferior supply can cause irreparable damage
to your 12 Volt system, but the use of an Orion voltage converter
prevents problems of that type.

The Orion 24/12-20 and 24/12-30 can also be used as a 13.8 Volt battery
charger for a 12 Volt starter or accessory battery in an otherwise 24
V system.

The article 4397-082 is waterproof.