DURITE 10Amp 12v > 24 volt split charge (VSR) relay
Steps12volt up to 24volt to charge a 24volt battery or to operate 24 volt accessories
Zero loss Split Charging
Fully automatic operation
‘Connected’ LED indicator
Ignition Protected
Very simple to install, does not require a connection to vehicle alternator
12 volt dc to 24 volt dc 10 amp split charger. Designed to charge and maintain a 24 volt auxiliary battery from a 12 volt dc system. It has a three stage micro processor controlled charging system and uses voltage sensing for automatic cut in and drop out of charge from the 12 volt system, so will not charge the 24 volt auxiliary battery until the 12 volt vehicle battery is charged or being charged.
Only 4 Connections to make
Power in, Power out & negatives...that's it!
The idea of a "voltage sensitive relay" (VSR) or "voltage controlled relay" (VCR) as they are sometimes known, is to simplify the installation, no connection is made to the vehicles alternator .
Simply connect this relay to the towing vehicles positive battery terminal (via a fuse!) and link to the 24 volt circuits
The relay monitors the towing vehicles battery voltage and when it reaches 13.3vdc, the relay switches on and supplies charging current to the 24 volt circuits. When the engine is stopped and the voltage of the vehicles main battery drops below 12.8vdc the unit switches off.
Only 4 connections are required to the unit and as such it can be fitted in next to no time .
Supplied with detailed full instructions.
https://www.durite.co.uk/WebResources/Common/Docs/technical_sheets/801-900/0-852-51%20spec.pdf