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Battery Isolator Relays

You want to charge more than one battery at the same time with only one power source? Then a battery isolation relay is just the thing for you. Thanks to its advanced technology, it efficiently distributes the charging current to up to three batteries at the same time without losing voltage. At Offgridtec you will find the perfectly suitable 12V or 24V battery cut-off relay for your needs. Browse through our online shop now and see for yourself!

Types of battery cut-off relay

A relay is an electrical switch with two positions. It is used, for example, in motorhomes to separate the on-board battery from the starter battery when stationary and to connect them for charging. Depending on the design and mode of operation, you will find two different types of isolating relay in our online shop, in addition to a range of useful battery accessories:

  • simple
  • automatic

The simple disconnect relays require a switching signal from the alternator (or other power source), while a fully automatic battery disconnect relay connects the batteries as soon as a battery reaches 13.7V and disconnects them as soon as a battery drops below 12.8V.

Buy best quality battery disconnect relay online at Offgridtec

At Offgridtec you will find both simple and electrical cut-off relays in top quality and at the best prices. Our experts only select high-quality products from renowned manufacturers for our online shop and will be happy to answer any questions you may have about our products.

We will be happy to advise and support you in finding your suitable battery cut-off relay. You can reach us on +49 8721 91994-00 to take advantage of our expert advice for private customers and specialist dealers. We are also happy to receive an e-mail at [email protected]!


  1. What does a battery disconnect relay do? With a battery cut-off relay, several batteries can be charged simultaneously from one power source without the batteries being connected to each other. As soon as one of them reaches 13.7V, the cut-off relay switches on so that both batteries are charged at the same time.
  2. Which pole must be connected first when installing a cut-off relay? The red cables are connected to the positive terminal first, the black cables then to the negative terminal of the battery.
  3. How do I charge the starter battery in the motorhome? An isolating relay or a charge booster can be used to charge the starter battery while driving. This switches both batteries in parallel and ensures that both batteries are charged via the alternator.