Victron SolidSwitch 104 - BMS800200104

The Victron SolidSwitch 104 switches DC loads up to 70 V/4 A and can be controlled by a low-power digital signal. It has three typical use cases:
1. Control an external alternator regulator, such as a Balmar or Mastervolt Alpha pro on a Victron lithium system.
2. Switching a DC load, such as a light. A low power control circuit, the maximum current drawn will only be 100 μA, can control a load up to 4 amps.
3. Increase the number of chargers that can be connected to the ATC (charging authorisation) output of a Victron BMS.

What makes the Victron SolidSwitch 104 unique?

The feature that makes it such a useful switch is its low current consumption. The Victron SolidSwitch 104 will consume 0.04 Ah per month, whereas a small relay can easily take 10 Ah per month, or even 22 Ah (*).

That reduction by a factor of 250 is crucial when used in a lithium system to connect and control the alternator regulator: the control circuit will always be drawing its standby power. As well as when used to increase the number of chargers that can be connected to a BMS ATC contact. By using a Victron SolidSwitch 104 instead of an ordinary relay, the parasitic load is reduced to the order of magnitude of the self-discharge of the battery bank.

Note that even when the batteries are fully charged, the ATC output of the BMS will still be enabled. And as such, control circuits such as a relay or, in this case, the SolidSwitch, will be enabled and consume power. Even when the charger or alternator is not charging.

For this example, that means that when using a relay, the small relay consumes 10 Ah per month from the battery bank, even when the engine is not running. Whereas SolidSwitch only consumes 0.04 Ah, which is most likely well below the self-discharge of the batteries and therefore negligible.

Compatible charging types

The DC load can be resistive, capacitive or inductive (such as the coil of a high power contactor).

Datasheet Victron SolidSwitch 104 - BMS800200104

See Victron SolidSwitch 104 - BMS800200104 datasheet