Whether you’re using AGM, Lithium, or another type of battery, your batteries are one of the most costly and vital parts of your build. Here’s what you can do to optimize your power system for the long run and ensure you stay safe and efficient.
Over years of building out solar power systems in vans, we have discovered a few important things that we notice many DIY van builders aren’t addressing in their van builds. Namely, people are connecting their batteries in parallel and going directly from one of the battery’s positive terminals to the rest of the system. Although that will work for awhile, it also causes unseen damage to the battery that is furthest away from the final output. Additionally, it doesn’t allow your battery bank to properly balance out and reach an equilibrium. This can cause headaches as you troubleshoot your power system and can’t figure out why your readings are off, or why one of your batteries suddenly failed on you.
Using a product like Victron Energy’s Lynx Power In allows you to avoid the issue above and keep your batteries in equilibrium. You simply connect all of the positive and negative terminals to the Lynx and there is a single positive and negative output from there to the rest of your system. Another important factor to keep in mind is whether you need to install terminal fuses (you’ll need both THIS and THIS for each battery terminal, so two sets per battery). Most batteries DO NOT come with built-in fuses, so you’ll likely need to complete this step. The reason you’ll need these is that without them, if one of the cells in one of your batteries goes bad, it can in essence short everything else in your system out. By installing these, in the case that one of your batteries fails in the future, it’ll just affect that battery and not the whole system.
The importance of correct wire sizes
This is another aspect of your electrical system that you should consider carefully. Each part of the system will require various sizes of wire depending on how much power is ultimately running through them. The size will be based on the number of amps running through the system. For example, the inverter that’s pulling a bulk 120V charge and running all of your 120V appliances will typically have large 4/0 wires. Many of the appliances will have a wire gauge suggestion in their manual (solar chargers, inverter chargers, etc). Renogy has this calculator to help you calculate which sizes of wire you will need.