Battery Switches, Selectors & Relays

Battery Isolator Switches, Selectors and Smart Relays for 12V to 48V Systems

Every DC power system needs a safe way to disconnect, combine or switch between battery banks. This collection covers manual battery isolator switches, 3 and 4 position battery selector switches, enclosed 2-pole DC circuit breakers, voltage sensitive relays and low voltage disconnects from Blue Sea Systems, Victron Energy and ZJBeny. These components suit caravans, RVs, 4WDs, boats, trucks and off-grid tiny homes running 12V, 24V or 48V.

Manual Battery Isolator and Selector Switches

A 12V battery isolator switch gives you a physical disconnect point between the battery bank and your loads, so you can shut the system down for servicing, storage or emergencies. The range of on/off and dual circuit battery switches includes the compact Blue Sea Mini m-Series at 300A, with key and lockable key versions, plus the Blue Sea e-Series at 350A, the Victron 275A battery switch and 300A and 350A on/off switches in red or black. For larger marine and commercial banks, the Blue Sea HD-Series 600A switch is available with or without AFD (Add-A-Field Disconnect).

Battery selector switches let you run from battery 1, battery 2 or both. Choose 3 position (OFF/1/2) or 4 position (OFF/1/2/1+2) models in 300A Mini m-Series and other 300A options, the 350A e-Series with AFD, or the 500A HD-Series for heavy-duty applications.

Automatic Combiners, Charge Relays and Low Voltage Disconnects

Where switching should happen automatically, Victron Cyrix-ct battery combiners (120A and 230A) and the Cyrix-i 400A connect start and house batteries when charging voltage is present. The Blue Sea ML Series 500A Auto Charge Relay suits 24V systems. If you are switching an RV to lithium batteries, Cyrix-Li charge and load relays work with a lithium BMS to control charging sources and loads at 12/24V or 24/48V.

Victron BatteryProtect low voltage disconnects (65A, 100A and 220A, plus a 48V 100A version) cut loads before a battery is over-discharged, with Smart Bluetooth models allowing setup from your phone.

Enclosed DC Breakers and Grid-Tie Relays

ZJBeny 2-pole DC circuit breakers with enclosure (125A, 160A and 250A) combine overcurrent protection with a manual isolation point. For dedicated solar isolator switches and PV breakers, see our DC circuit breakers and enclosures. Grid-connected ESS installs are supported by the Victron Anti-Islanding Box 63A, the Ziehl UFR1001E relay and the Victron SolidSwitch 104.

Sizing and Selection Tips

• Rate for continuous current: choose a switch or relay with a continuous rating above your highest sustained load, including inverter draw. Our guide on why continuous ratings prevent fires and equipment failures explains why peak figures can mislead.
• Match system voltage: confirm 12/24V or 24/48V compatibility, especially for Cyrix and BatteryProtect models.
• Manual or automatic: use selector switches for hands-on control and VSRs or Cyrix-Li relays for set-and-forget charging.
• Lithium systems: pair Cyrix-Li relays or BatteryProtect units with a BMS that provides the required control signals.
• Security: key and lockable key switches help prevent unauthorised use in vehicles and vessels.

Compare continuous ratings, voltages and switching styles above, then order the battery switch, selector or smart relay that fits your setup. Contact our team before you buy if you need help matching a component to your system.