How to Install Auxiliary Battery in a Camper Van, motorhome or home vehicle.
We get many questions every day asking How do I install the auxiliary battery? how to install second battery? How do I connect the Automatic Relay? What cable do I need to install batteries?? and others of the same type.
Well, we are going to try to clear up the doubts to install auxiliary battery in van, clarifying certain topics and always from our experience and practical point of view.
Any vehicle that we want to use as a home and install devices with electrical consumption in it, whether it is a van, a car, and 4×4, a truck or a boat and use them with the car engine stopped, We must install one or more auxiliary batteries so as not to discharge the main battery.
Which battery is best for Auxiliary?
Today, la mejor bateria para una camper, es una bateria Lifepo4.
Auxiliary Battery Installation Methods
Installation with a common relay
And Relay no deja de ser un interruptor, to which if you give it current it turns open and vice versa.
Estos Reles son muy económicos y fáciles de encontrar, the inconvenient (yes it is) is that in the installation to activate it we must give it an electrical impulse for it to activate, for example through the alternator or contact.
The rest of the installation is as usual, the positives of the batteries joined together, with the Relay in between, con 2 fusibles en los extremos cerca de los bornes, y los negativos a masa o chasis.
Installation with Automatic Relay
Un Relé Automatic es como el común pero al que le han añadido un circuito electrónico, Its function is that when the Relay receives current greater than 13.5v. It will be activated and when the current drops below 12.6v. will be deactivated. Eso es en los clasicos como el Victron Cyrix, pero si montas una bateria lifepo4 tienes que utilizar este otro tipo de rele automatico, porque es “configurable” y puedes ponerle que se active a 13.9 y que se desconecte a 13.5v, de lo contrario no separaria las bateriaspracticamente nunca.
Thus, It is not necessary to power the Relay and the installation is quite simple., the Relay between the positives of the batteries and the negatives to ground or chassis.
He Relé Automático ajustable es más caro que el común pero la instalación también es más simple, It does not involve other parts of the car and is cleaner as it has less wiring..
Este relé ha sido especialmente creado para instalar en un vehiculo a motor, como una camper o autocaravana.
Automatic relay connection
I will also explain how to connect correctly using the Nagares automatic relay for its correct operation.
He automatic relay dispose of 3 pins that are marked with numbers 30, 87 y 86
I put a picture that is worth a thousand words!
The no. 30 It has to go to the main battery, he 87 to the secondary battery and the 86 a time. Más simple imposible 😉
Last price update on 2026-10-03 at 21:17 Fuente: Amazon Affiliates
