Skip to Main Content »

Security Seals

Welcome to Impact Battery!

Battery Tales: Does Every Charge Cost a Cycle?

I was doing some research the other day and came across an article that sounded promising. The blog article “Make Your Battery Last” dealt with proper maintenance for motive batteries installed in lift trucks, forklifts, and electric pallet jacks.

However, as I got deeper into the writing, I began to suspect the article was written by a paid guest; an outsider to the industry. It started to have a regurgitating-freshly-learned-information feel, rather than one that came from an experience-based authority on the subject. I grew uneasy when I read: “each charge costs a cycle” in a section talking about opportunity charging.

Opportunity Charging Your Pallet Jack

What is Opportunity Charging?

Opportunity Charge: Charging your batteries several times during the work cycle.

It’s no secret that a beverage route driver from say Coca-Cola, may utilize an opportunity charge while setting up a display at Walmart or another big box store. Due to the expense, many of these food companies have delayed the purchase of new pallet jack batteries and the situation gets further exasperated by poor battery maintenance.

These route drivers use electric pallet jacks to move product from truck to store. In our Coke/Walmart example, the driver takes full advantage of the time it takes to set up a store display by plugging in to a nearby AC outlet. This 20 or 30 minutes or more of charge is often needed just to power through the remainder of the day.

Theory: Every Charge Cycle Shortens a Batteries Lifespan

In the article that spurred this written response, an illustrated statement is used indicating a certain battery will have 1500 cycles. Based on a typical work week, it would be discharged and re-charged around 300 times a year equaling a five-year lifespan. It went on to say, “Do not opportunity charge (i.e. charging during lunch breaks). If you charge your battery twice a day you will still get your 1500 cycles, but the [battery] will be used up in 2.5 years instead of 5.”

Here is why the authors statement is misleading. It places the emphasis on the notion that charging—any type of charging—is what counts against your batteries cycle life.

Response: DoD is the Most Relevant Factor that Governs Battery Life

I would propose that Depth of Discharge (DoD) is the primary factor (outside poor maintenance) that governs the longevity of your battery. Similar to a mechanical device that wears out faster with heavy use, the depth of discharge determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last.

Dod vs. Charge Cycle

Our example chart shows how a certain battery has 675 cycles when regularly discharged to 80%. But the same battery has 7000 cycles when discharged to only 10%. If the notion that each charge uses up a cycle then there is no way we could reach 7000 cycles. This chart would be a flat horizontal line regardless of DoD since the determining rate of decay is the number of charges.

This manufacturers chart, and many others like it, supports the argument that there is no need to avoid an opportunity charge. To use our contested authors example, it would be safe to say opportunity charging is NOT shortening the useful life of your battery from 5 to 2.5 years.

Don’t get too excited. There is also evidence suggesting that since opportunity charging does not always bring a battery back to full charge or in some cases shocking the battery with high current over lunch breaks is not the most helpful method to extend long-term battery life.

Bringing a battery to full charge, regardless of DoD, immediately after use and then letting the battery effectively cool before being placed back into service is the key to maximizing a batteries useful life span. But the limitations of lead acid technology often leave companies focusing on the here and now blinded by the daily grind.

So, we may not be cutting the life of the battery in half by charging twice a day as the author suggested. But it does appear we are shortening the batteries life to some degree. Undeniably, this is magnified by poor battery maintenance (i.e. not properly watering, leaving batteries in a prolonged discharged state, etc.). Of course utilizing a high quality smart charger that is durable enough to withstand the many abuses these applications encounter is perhaps half the battle.

Leave the Opportunity Charge Behind!

For many, opportunity charging is a necessary evil, especially for those in the food and beverage industry—a forever annoyance for hard working individuals employing lead acid batteries. Of course, one could avoid this hassle altogether by switching to an EnerPro lithium battery.

We have some multi-national companies going 1-3 weeks without needing to re-charge. These same companies used to struggle to get through a day or at best would make it through a couple days with lead acid batteries installed in their pallet jacks.

By switching, they have eliminated maintenance costs and productivity loses associated with lead acid batteries. Slow moving or scuttled jacks do not make money. So isn't in your companies best interest to keep those machines running for as long and as efficiently as possible?

As we did with them, we can help you overcome that problem. Email us to get a free copy of our “EnerPro Lithium Battery: Move More with Less” mini-white paper. It’ll introduce you to a better way of doing business and show you how to eliminate the need for opportunity charges, increase productivity and ultimately help your company save and make more money.