Victron SolidSwitch 104
A 70V/4A Solid State Switch
Product Overview
The SolidSwitch 104 switches DC loads of up to 70V/4A and can be controlled by a low power digital signal. It offers three typical use cases:
- Control an external alternator regulator, such as a Balmar or Mastervolt Alpha pro in a Victron lithium system.
- Switch a DC load, such as a light. A low power control circuit, drawing a maximum of 100 μA, can control a load of up to 4 Amps.
- Increase the number of chargers that can be wired to the ATC (allow-to-charge) output of a Victron BMS.
Unique Features: Ultra-Low Current Draw
The SolidSwitch 104's standout feature is its exceptionally low current draw. It consumes only 0.04 Ah per month, a significant improvement compared to small relays which can draw 10 Ah or typically 22 Ah per month (*). This reduction by a factor of 250 is crucial for lithium battery systems, especially when controlling alternator regulators or expanding charger connections to a BMS ATC contact. Using the SolidSwitch instead of a standard relay minimizes parasitic load, often falling below the battery bank's self-discharge rate.
Even when batteries are fully charged, the BMS's ATC output remains enabled, powering control circuits like the SolidSwitch. This means the SolidSwitch draws power even when the charger or alternator is not actively charging. For example, a small relay drawing 10Ah per month would drain the battery bank even when the engine is off, whereas the SolidSwitch's 0.04Ah monthly draw is negligible compared to typical battery self-discharge.
(*) For example, a 12V 1A relay with a 400 Ohm coil draws 30mA, equating to 21.6 Ah per month.
Compatible Load Types
The DC load can be resistive, capacitive, or inductive (such as the coil of a high-power contactor).
Technical Specifications
| Product | SolidSwitch 104 |
| Operating Input voltage range (Vbat) | 8 - 70V DC |
| Maximum load current | 4A |
| Maximum capacitive load | Vbat up to 15V: 1000 μF 15V<Vbat<30V: 400 μF 30V<Vbat<70V: 50 μF |
| Maximum inductive load | Up to 1A: 1000 mH 1A<I<2A: 100 mH More than 2A: 10 mH |
| Remote input (Vin) | Free floating or Vin< 3V: load off 3.3V < Vin < 70V: load on Min. input current to switch on: 30 μA |
| Operating temperature | -20 to +50°C (0 - 120°F) |
| Humidity | Max. 95% (non-condensing) |
| Protection grade | IP20 |
| Material and colour | ABS, matt black |
| Dimensions (h x w x d) | 58 x 66 x 23 mm |
Application Diagrams
Diagram 1: Illustrates the SolidSwitch 104 used with a Victron smallBMS to control an alternator. It shows the SolidSwitch connecting the battery and load, and being triggered by the smallBMS's ignition signal.
Diagram 2: Demonstrates the SolidSwitch 104 integrated with a Victron VE.Bus BMS for alternator control. This diagram highlights the connections between the battery, SolidSwitch, VE.Bus BMS, and the alternator regulator, showing how the BMS manages the SolidSwitch's input.
