Stay in Charge

Why your dual-battery system is incomplete

With the Easter holidays just weeks behind us, there’s a good chance that your auxiliary battery is in desperate need of maintenance, and an even better chance that permanent damage is happening to the battery as we speak. But don’t fret; there’s still time to save your battery and prolong its life. This is what you need to do …

A lot can be said about battery life and how it relates to recharge rates, but in the interests of simplicity, here’s the gist of it: a deeply discharged battery must have enough TIME to recuperate.

There’s a popular misconception that a battery can rapidly recharge in a short space of time. This is simply not true for most batteries. Unfortunately, very few battery manufacturers and fitment shops are conveying this message, and, as a result, overland travellers are paying the price… literally.

The graphs below highlight a few critical lessons about dual-battery ownership, using a popular 105Ah (wet cell) deep-cycle battery as an example:

Discharge graph

This graph shows how much (useable) energy can be drawn from a 105Ah deep-cycle battery. The highlighted region depicts the safe operating area, and equates to a 70% depth of discharge. In other words, you don’t get 105Ah from a 105Ah battery!

Generally speaking, you can draw between 70 and 75Ah of useable energy before entering the deep discharge area where battery damage is accelerated and the life of the battery is shortened.