How long do lithium golf cart batteries last?
Two ways to calculate your lithium battery lifespan
Lithium battery technology is transforming the golf cart industry. Cart owners everywhere continue to make the switch.
The long lifespan of lithium is one of the main reasons it's becoming a popular choice in the market. Lithium batteries can last over a decade. However, not every battery will meet those expectations. Lithium-ion batteries on the market vary widely.
Is it possible to estimate how long your battery will last? In this article, we'll cover two aspects of lithium battery longevity:
The expected range of a single charge
The expected total lifespan of the battery
The battery longevity calculation
Every battery has performance data that provides important information. Certain terms and specs are useful for calculating battery lifespan.
Maximum discharge rating: The maximum amount of power the battery can supply over a certain period. This number can be broken down into continuous, instantaneous, and pulse discharge
Amp-hour rating: The maximum amount of power a battery can supply for one hour. Think of this as the battery’s fuel tank.
With these numbers, it's possible to calculate runtime and range.
Calculating battery runtime and battery range
The resulting calculations look like this.
Runtime. 170 amp hours/250 amps = 0.68 hours of run time.
Range. To calculate mileage/range, you need the speed at that amperage. Every cart will vary.
0.68 hours x 40 mph = 27.2 miles
Adjusting for typical golf cart use
A golf cart driver would only rarely require 250 amps of a battery for forty consecutive minutes. A more realistic calculation might look like this:
170 amp hours/45 amps = 3.8 hours
3.8 hours x 20 mph = 76 miles
Seventy-six miles of range from one charge is close to the peak of what’s available today. Always keep in mind that driving style, terrain, temperature, elevation, and more can heavily affect the range.
The importance of battery efficiency as a factor
Efficiency also affects both length of charge and battery lifespan. The amp-hours (Ah) number indicates how much power a device uses during one charge.
However, it does not tell you how much power is available for your golf cart. This is important because inefficient batteries provide less energy to the cart because they waste more of it as heat. The result is an actual runtime that comes in below the amp-hour rating.
Moving electrons creates heat, and heat isn’t power to the wheels. So, the more efficient the battery, the more power you can actually get out of it. Just because it says 100 amp-hours of input doesn’t necessarily mean you’ll get 100 amp-hours out of it, because there is more than one way that power can be consumed. When you’re talking about what differentiates a cheap battery from a high-quality battery, a lot of it can be what’s inside the battery. The right materials make it efficient and get that true amp-hour rating.”
Neil Carder, Trojan Lithium Product ManagerMeasuring total lithium battery lifespan
Cycle life measures the total lifespan of a lithium battery. It represents the number of charges and discharges that a battery can complete in its lifetime. Experts do not recommend discharging lithium batteries to 0%. That's why each cycle life rating comes with a depth of discharge number.
Trojan bases battery cycle life on a 30% depth of discharge (DoD). This means one cycle uses 70% of the battery's full charge.
Trojan OnePack lithium battery packs achieve 4,000 cycles at 30% depth of discharge. Products by other lithium battery manufacturers rarely exceed 3,000-3,500 cycles. Numbers vary from manufacturer to manufacturer, and some do not publish their depth of discharge or cycle life numbers.
An owner's cart and driving style can also greatly affect the total range.
Calculating lifespan with Ah and cycle life
For hypothetical purposes, let’s look at some rough estimations of the total lifespan.
105Ah / 35 amps = 3 hours
3 hours x .7 = 2.1 hours
.7 represents the 70% depth of discharge that is considered one cycle by Trojan
2.1 hours x 20 mph = 42 miles
42 miles x 4,000 cycles = 168,000 miles per lifespan
The same calculation at 3,000 cycles would give you 126,000 miles per lifespan. This is before factoring in the potential efficiency differences described earlier.
The dramatic difference efficiency makes on lifespan
If a 105Ah battery performs more like a 90Ah battery, the range changes dramatically. From ~168,000 miles, it shrinks to about ~108,000 miles. That means that although both batteries are 105Ah, one will last up to 35% longer.
Of course, the actual power draws of the carts influence the real outcomes, and these draws can vary. Capacity loss over the lifespan of the battery will also occur, so these calculations are for demonstration purposes. You will not go 168,000 miles on a single battery.
The point is that you cannot assume two lithium batteries with equal Ah ratings have the same lifespan, as they will have different ranges on a single charge and a different number of total charges included in their overall life.
Focus on data and specs to make your decision
To choose a battery for optimal lifespan, buyers need to look closely at specifications, including:
Amp-hour or Ah (sometimes referred to as capacity, nominal capacity, or capacity amp-hours)
Maximum discharge (continuous, pulse, and instantaneous)
Cycle life
DoD (depth of discharge)
If you are considering buying a battery, ask for these data points from the dealer. If the manufacturer does not publish them, you may not have the information you need to make an informed choice. You can find all these specs and more on every Trojan datasheet.
So, how long is a lithium battery’s lifespan?
From efficiency to cycle life to usage, many factors influence lifespan. Most industry experts agree that a decade of performance is reasonable for today's lithium-ion batteries.
Trojan builds batteries that are on the high-end of performance, quality, efficiency, and cycle life. That's why we back up our OnePack lithium batteries with a 10-year limited warranty.
Authorized Trojan dealers can help you pick a battery that fits your performance and lifespan needs. Find a dealer near you.