By Aaron Plew – Product Director at Fullriver Battery USA
Not all AGM batteries are created equal. The difference between a Fullriver AGM and Brand X is often worlds apart. From the purity of the lead, or the thickness of the plates, to the extra time invested in the plate curing process. So, today we’ll talk about what we know on an intimate level, Fullriver premium AGM batteries.
Context, Context, Context.
How long? A question that humans have been asking seemingly since the beginning of time. How long will I live? How long until I can retire? And of course, the ubiquitous, “How long until we get there?” Questions like these are best answered by looking at the specifics of each situation. How long will I live? This largely depends on where and how you live and some good luck with your genetics. How long does an AGM battery last? While Fullriver batteries have a 10-year design life, this must be put into context with several factors.
First, let’s talk about usage of the battery. Any battery has a finite amount of energy it can give over its lifetime. If every time the battery is used it is drained completely, the amount of time the battery will last is less than if the battery was used moderately and then recharged.
Golf is a good example application to better understand the concept. Batteries used to play two to three rounds of golf before being recharged will not last nearly as long as a set of batteries used to play one round of golf before being recharged. The amount of energy removed from a battery is known as Depth of Discharge (DoD). Fullriver’s Cycle Life vs. DoD chart is a great reference for understanding the impact of battery usage:
We can see from the above chart how widely cycle life can vary based on usage. If every time the battery pack is used, it is discharged fully to 100%, we can expect ~450-500 cycles. Conversely, if only half of the usable energy is discharged, the cycle life will be somewhere around 1000 cyc
We could further discuss the impact that the rate of discharge has on the batteries (i.e., how fast the energy is removed from the batteries), but let’s keep this at a 30,000-foot view. Suffice it to say that the lower the energy demand on the battery, theoretically, the longer the usable life of the battery will be.
Charging is the fuel of a battery. Just like automobiles, high quality fuel produces the best performance and longevity. Charging batteries properly is perhaps the most important aspect of ensuring a set of batteries lasts as long as possible. A reputable charger should be used that includes an actual AGM setting. Avoid chargers that claim to charge any battery type using one generic algorithm. Additionally, the charger should at a minimum put out at least 10% of the battery’s rated capacity in amperage, but ideally the output will be closer to 25% of the rated capacity. Look for a charger that approximates our recommended voltage for each phase of charging.
A note about PSoC
It is critical that the batteries are not left discharged for long periods of time between usage, commonly referred to Partial State of Charge (PsoC). This does not mean that the second a battery has been discharged it must be recharged immediately, but it does mean that a battery should not sit for days until it is recharged. If battery usage is light, a complete, uninterrupted charge once a week should be sufficient. For heavier use applications, a complete charge cycle may be required daily.
Not too hot, not too cold, but just right. Of all battery chemistries, AGM batteries are documented to perform the best in the cold. While all chemistries suffer temporary capacity loss in the cold, AGM seems to fair the best when compared to lithium, flooded, or gel batteries. On the other end of the spectrum is, of course, heat. For any lead-acid battery, heat degrades cycle life. Specifically, every 12°C (22°F) over 25°C (77°F) can reduce battery life by as much as half. The Fullriver cycle life graph is based on cycling at a constant 25°C (77°F). In the real world, temperatures fluctuate by season, and even between night and day.
The right tool for the right job
Just like using a screwdriver that is one gauge too small or large can create frustration, and a stripped screw head occasionally, batteries are designed to tackle specific needs. Using an automotive starting battery to power a golf cart would be disastrous. But the design specification is even more tightly focused when it comes to deep-cycle and dual-purpose batteries.
Deep-cycle batteries like the Fullriver DC or EGL Series are designed to run a purely electrical application until their energy is depleted and then be recharged. They were designed to do this process on repeat, discharge, recharge, and so on. While they can start an engine reliably, this wasn’t part of their design intent. Plus, they can be more expensive when the extra cost may not be warranted.
Dual-purpose batteries like Fullriver’s Full Throttle series are a hybrid in that they are very capable when starting an engine, but they have a specialized grid design (Thin-plate, pure-lead) that also allows them to do some cycling. Full Throttle excels in applications like marine where they serve to start the engine and also need extra capacity to keep instruments running, especially with the engine off for short periods. For pure cyclic applications like mobility, they just won’t have as long of life as a true deep-cycle battery.
We can see that there are many factors to consider in predicting the life of a battery. Starting with the highest quality battery, and accounting for usage, charging, climate, and the needs of a specific application are all relevant to determining how long a battery is going to last. With all of these factors optimized, we can expect battery life to go on long after the manufacturer’s warranty has expired.
We want to hear from you! What has your experience with battery life been? How are you maximizing battery life?