The most effective way to wire up a second battery is to connect them both in parallel so they both do the same job. Following your recent explanation of the benefits of fitting two batteries, I am ...

I have a Sears deep-cycle lead-acid 12v battery already which I've only used once or twice a year for certain power applications. I was thinking of purchasing an identical model and wiring it in ...

For those willing to put some elbow grease into it, there is an almost unlimited supply of 18650 lithium ion batteries around for cheap (or free) just waiting to be put into a battery pack of some ...