Many drivers look for the best deep cycle battery charger in order to avoid frequent charging. However, it is worth understanding that hours of discharge depend on the parameters of a battery and the power consumption of your engine rather than on the charger’s parameters.

To find out a run time of your unit, you should conduct certain calculations according to the formula provided in this article.

## Run time and lifetime: what is the difference

Auto fans often find it challenging to determine operation parameters of their batteries. Apart from manufacturers’ official websites, there are many blogs and forums overcrowded with amateurs providing misleading information. For example, online “experts” often muddle up the terms “run time” and “lifetime”. To clear the air, let’s consider the definitions of both:

- Run time is a full cycle between two charging sessions when the energy level drops from 100% to 0%
- Lifetime (or lifespan) is a period from a new battery’s purchase to a moment when you decide to get rid of it and buy another one

Therefore, lifetime consists of a certain number of cycles.

## How deeply can you discharge your battery

It is also important to understand what the term “depth of discharge” (DOD) means. It is a part of the charge already spent buy a device. For example, if 30% of energy is available, your unit is 70% DOD.

Regular 80% DOD can wear out the device two times faster than 50% DOD. Of course, if there is a force majeure and you need to squeeze 80% out of your unit, this quite can be done once or twice. But do not turn such use into a habit.

There is another extreme: some drivers recharge their batteries too often, hoping to extend a lifespan. But too low DOD is also undesirable. Let it reach at least 10%. Units regularly recharged at 5% or less die much faster. This happens due to lead dioxide surrounding positive plates.

## The formula for calculating run time

The rule of thumb is multiplying battery capacity (Ah) by 10 and dividing the sum obtained by load power (W):

(10*Ah) / W = run time (hours)

For example, your vehicle needs 200 watts. Your battery has a capacity of 100 Ah. Run time can be calculated as follows:

(10*100) / 200 = 5 hours

The battery can work 5 hours before it is totally discharged. Keep in mind that estimated value can be reduced due to improper installation.

## Helpful tips

As said above, manufacturers do not recommend discharging deep cycle batteries by more than 50%. You can exploit a unit only 2,5 hours before recharging. Otherwise, it will wear out faster.

Also, do not expect your device to have a 100% charge after prolonged storage. Up to 15% of energy is lost monthly. In addition, lead sulfation starts with 20% DOD and shortens lifespan. Therefore, you should periodically recharge your battery to ensure its smooth operation.