Lead acid batteries are still most widely used among boat and recreational vehicle (RV) owners because of their good performance, widespread availability and being relatively safe. With a low self-discharge, high specific power, well low and high-temperature performance, as well as a reasonable price tag will likely continue to be the common battery of choice for many years to come.
Lead-acid batteries are not very complicated to use and require little or none maintenance from the user perspective. However, there are some simple guidelines that need to be followed in order to keep your batteries in a healthy condition for a long period of time.
In this post, we will present them by answering the most common questions our customers ask about their batteries.
How often should I charge my batteries? Will I damage them by charging too often?
The more often you charge your lead-acid batteries the happier they will be. The number of charges does not shorten your batteries lifespan. When manufacturers state the number of cycles the battery should last that means the number of full battery cycles. One cycle means using 100% of battery’s capacity. In other words, if you discharge your battery from 100% to 0%, that counts as one cycle. If your discharge your battery from 100% to 50%, charge it back to 100% and discharge it again until 50% that also counts as one cycle! For example, if you discharged your batteries until 80% and then charge them back fully again, you did not “use” a full cycle, but only one fifth of the cycle.
You will not damage your lead-acid batteries by charging them too often. On the other hand, you will definitely damage them by charging them too little, or even worse, by leaving it uncharged for long periods of time, as explained later.
Should I deep discharge my lead-acid battery?
Lead-acid batteries do not like deep discharging at all. The deeper you discharge them, the shorter their lifetime. That also counts for deep-cycle type batteries – they are only a little less affected by it. It is recommended to stay within the barriers from 40% to 80% state of charge – the higher SOC the better. Using a battery monitor with precise state of charge monitoring, such as SIMARINE PICO, is a great tool that gives you an excellent overview of your battery state and exact information, when is time to start charging your batteries to prevent damages by discharging too deeply.
If I do not discharge my batteries fully, will that cause a memory effect?
Lead acid batteries do not have a so-called memory effect, so you do not need to worry about it. If you only discharge them by 80% and charged them back again that will not cause damage in any way.
How long does it take for a lead-acid battery to fully charge?
A fully saturated charge takes from 14 to 16 hours on average.
Is the temperature affecting my lead-acid battery performance?
Yes, the temperature is affecting your battery performance. The optimum temperature for batteries is around 20 °C, despite the fact that battery manufacturers state the nominal capacity at 27 °C. Operating a battery at elevated temperatures improves performance but shortens its life as the aging process is accelerated. At 30 °C the cycle life is reduced by 20%, at 40 °C, up to 40%. Cold temperatures also affect battery significantly. At -18 °C the battery delivers only 50% of its capacity, depending on the battery chemistry.
What is the approximate yearly self-discharge rate for lead-acid batteries if left unused?
The lead-acid batteries will self-discharge approximately 40% in a year.
How often should I charge my batteries if left unused?
It is very important not to leave your battery discharged for a longer period of times. Before you leave, always charge them fully. The low charge causes sulfation, a condition that robs the battery of performance. It is necessary to charge your batteries at least once per 6 months to maintain a healthy condition.