I'm thinking of adding a second leisure battery, what do I need?


If you have an existing set up which is already in place then adding a second battery to give you a bit more time between charges can be a great idea. Here's a couple of things that might need to be tweaked electrically in order to accommodate the extra battery power you're adding. 


  1. If you have a mains hook up, you might need to swap your mains to leisure battery charger for a larger one. See here for more information on this. 
  2. You will need a set of wires to join the two batteries together. We call these battery linking wires. for a 12V system using 12V batteries, you want to join them in parallel. So positive to positive and negative to negative. 
  3. You will need to make sure that you have all of the positive wires coming off of one battery and all of the negative wires coming off of the other battery. This way they will charge and discharge as a unit, rather than one draining and the other trickling charge back in. The latter scenario will shorten battery life. More information on wiring batteries in parallel. 
  4. The size of your split charger. In most cases split chargers are very heavy duty and capable of taking almost the alternators full output. However, particularly if you have a battery to battery charger and a large leisure battery bank (over 300-400Ah). Then you might need a second or bigger battery to battery charger. 


The only other things to consider are whether you have the physical space for the extra batteries, it's much better if they can be sat side by side. 


The second battery should also be the same model, ideally, as the first battery for a better balance. It's not normally a good idea to pair an old declining battery and a new battery together as when the old one fails, it may damage the new one. If you have an old battery that's losing it's capacity, then it may be worth swapping this out too. 


We hope this helps, if you need any help with the above, please let us know.