Victron Cyrix dual battery combiner:
Some battery combiners will disconnect a battery in case of a short but high amperage load. A battery combiner also may fail to connect a large but discharged battery bank because the DC voltage immediately drops below the disengage value once the batteries are connected. The software of the Cyrix-i does more than simply connect and disconnect based on battery voltage and with a fixed time delay. The Cyrix-i looks at the general trend (voltage increasing or decreasing) and reverses a previous action only if the trend has reversed during a certain period of time. The time delay depends on the voltage deviation from the trend. In addition, four switch timing profiles can be chosen (see back page).
12/24 V and 24/48 V auto ranging- The Cyrix-i automatically detects system voltage.
No voltage loss- Cyrix battery combiners are an excellent replacement for diode isolators. The main feature is that there is virtually no voltage loss so that the output voltage of alternators or battery chargers does not need to be increased.
Prioritizing the starter battery- In a typical setup the alternator is directly connected to the starter battery. The accessory battery, and possibly also a bow thruster and other batteries are each connected to the starter battery with Cyrix battery combiners. When a Cyrix senses that the starter battery has reached the connect voltage it will engage, to allow for parallel charging of the other batteries.
Bidirectional voltage sensing and power supply from both batteries- The Cyrix senses the voltage of both connected batteries. It will therefore also engage if for example the accessory battery is being charged by a battery charger. The Cyrix-i has a dual power supply. It will therefore also close if the voltage on one battery is too low to operate the Cyrix. In order to prevent unexpected operation during installation or when one battery has been disconnected, the Cyrix-i will not close if the voltage on one of the two battery connections is lower than 2 V (12 V battery), or 4 V (24 V battery) or 8 V (48 V battery).
Parallel connection in case of emergency- The Cyrix can also be engaged with a push button (Cyrix remains engaged during 30 s) or a switch to connect batteries in parallel manually. This is especially useful in case of emergency when the starter battery is discharged or damaged.
Cyrix-i 12/24-400 Cyrix-i 24/48-400
2000A during 1 second
Input voltage 12/24 V model
Input voltage 24/48 V model
Over voltage disconnect
16 V / 32 / 64 V
Current consumption when open
Yes, 30 s
Micro switch for remote monitoring
Weight kg (lbs)
Dimensions h x w x d in mm
(h x w x d in inches)
78 x 102 x 110
(3.1 x 4.0 x 4.4)