Lead Acid VS Lithium-Ion Golf Cart Batteries?
New Golf Cart battery models have gotten a lot of press lately, but energy storage has been around for decades. With growing interest in batteries, battery technology has skyrocketed. Golf Cart battery models being released today are more exciting than ever, with innovative improvements in nearly every aspect. But which is better for your golf cart? Lead acid, or lithium-ion batteries? We’ve done the research, but we’ll let you decide.
New Battery Technology
Though lithium-ion battery technology was introduced in the 1970’s, it took forty years for it to really gain popularity. Lithium, the lightest of all metals, has the greatest electrochemical potential. This means that lithium provides the highest energy density per weight--far lighter and more efficient than the popular lead acid battery. Lead acid 48 volt battery packs can weigh up to 350 pounds, making them far more difficult to transport. Lead acid battery weight also makes usability much less with cart performance for our customers.
The growth of lithium ion technology has brought along with it many advantages. In comparison to lead acid batteries that have been popularly used in the past, lithium-ion batteries are 2/3 lighter, cleaner, live longer, recycle better, and require much less maintenance. But the advantages don’t stop there. Keep reading to find out how lithium-ion batteries make our golf carts not only cleaner, but smarter, too.
Not Just a Fair-Weather Battery
One major downfall of the lead acid battery is that its power capacity drops significantly in colder temperatures. In 0 degree Fahrenheit temperatures, a lead acid battery’s capacity is only 40-60% of its overall potential. This means that cold weather greatly decreases the amount of energy a lead acid battery can store, and with it, limits the amount of power your cart has available on a cold day.
The same low temperature of 0 degrees Fahrenheit will only take a lithium-ion battery down ten percent or so. This means that even when your cart battery gets cold, it can still store and provide your cart with almost as much power as it would on a normal day. Lithium-ion battery capacity is there for you, whatever the weather.
Cleaner Clean Energy
As far as environmental impact goes, lead acid doesn’t impress. Lead acid batteries require many times more raw materials than a lithium-ion battery to achieve the same level of energy storage. More raw materials means more mining, and a bigger environmental impact. The lead acid battery industry is also very energy intensive, requiring a lot of energy to even produce the battery itself. This leads to large quantities of pollution being dumped into the air, and into the environment.
Lithium-ion solar batteries have a significantly higher life cycle than lead acid batteries do in deep discharge applications. This means that lithium-ion batteries can support a higher number of complete charge/discharge cycles before their capacity falls under 80%. Recent data shows that a lead acid battery would have to be 2.5 times larger in capacity than a lithium-ion battery to get comparable life cycles.
The difference in life cycle is even greater in extreme climates. In warm climates where the temperature hovers around 90 degrees Fahrenheit, the difference in life cycle between lithium-ion solar batteries and lead acid batteries is huge. In these extreme temperatures, it takes less than 500 charge/discharge cycles for lead acid batteries to drop below 80% in retention, while lithium-ion batteries wouldn’t see that much of a drop until at least 2000 cycles. This huge jump in battery lifetime is an exciting development for golf cart owners who don’t want to worry about their capacity dropping when they need power the most.
This also means that lithium-ion batteries won’t require replacement nearly as quickly as lead acid batteries. After charging and discharging a lithium-ion battery thousands of times, it remains highly functional. Lead acid batteries decline much more quickly, leaving the battery owners with thoughts of replacement looming in the near future. More frequent replacement means less return on the initial investment made in each battery system.
Another inconvenience of lead acid batteries comes in the amount of maintenance each unit requires to prolong its battery life. Lead acid battery users need to keep track of battery voltage, water levels, overcharge functions, and routine electrolyte maintenance. All this information is necessary to make sure lead acid batteries are being maintained and serviced on a regular basis. Failure to track this data could result in even more costly repairs, or even earlier replacement of the battery itself.
Lithium-ion batteries, on the other hand, are virtually maintenance-free, allowing owners to enjoy using their golf cart battery without worrying about permanent damage due deep discharge. There are many other things in life that demand and captivate our attention. Your golf cart battery no longer has to be one of them.
The cost of transporting and installing lead acid batteries has been historically discouraging to golf cart owners. The sheer weight of lead acid batteries makes them difficult to transport, and harder to install. Because of the weight of lead acid battery materials, there is no easy way to cut this cost. Instead, many are turning to lithium-ion batteries to offer a lighter alternative.
Lithium-ion batteries weigh much less, lowering shipping costs by 80%. The installation cost of lithium-ion batteries are similarly. This makes the price of lithium-ion batteries considerably lower to ship and to install, making them much more appealing to consumers. With the rising demand for batteries across the country (and world), lower transportation and installation costs will become more and more important.
There’s our take on the lead acid vs. lithium-ion battery battle.
We’re pretty big fans of lithium-ion golf cart battery technology, so forgive our bias. Ultimately, it’s up to you to decide which battery technology is a better fit for your golf cart. Have more questions? We would love to keep this conversation going.
Don’t hesitate to call. 619 449-0822 The Sundance Team
If lithium cells are overcharged, it will shorten their lifespan or perhaps permanently damage them. So with a LiFePO4 (Lithium Iron Phosphate) battery whose nominal voltage is 3.2 volts you should never charge them above 3.65 volts and it is best to have something in the system that will shut the charger off when they reach a maximum charge voltage of 3.65 volts.
Similarly, with a LiNCM or LiMn204 (Lithium Polymer) battery whose nominal voltage is 3.7 volts you should never charge them above 4.2 volts and it is best to have something in the system that will shut the charger off when they reach a maximum charge voltage of 4.2 volts.
Conversely, a LiFePO4 lithium battery cannot be discharged below 2.4 volts without damage to the cells. So there must be some mechanism in the system which will automatically throttle back and eventually shut the battery pack down in the event of a discharge condition that goes below 2.4 volts. If that mechanism isn't in place you risk damaging some of the batteries in your pack. This system is commonly referred to as a Battery Management System or BMS or in the case of some smaller battery packs, like in a bicycle, a PCM.
A PCM (Protective Circuit Module), which is often called a PCB (Protective Circuit Board), is a passive system that will operate best at voltages of less than 96 volts and peak currents that never go over 200 Amps.
Having a number of batteries all connected up together storing electric energy is somewhat like having a barrel that is made from wooden staves which are of varying length that is storing water. Some batteries will accept a charge better than other batteries in the string. When they reach a predetermined voltage like 3.65 for LiFePO4 batteries then there has to be a way to shunt current from that highest charged battery and prevent it from becoming overcharged while their weaker batteries in the same string catch up. To simplify that I have used the storing water in a wooden barrel analogy and show the longer staves as the good batteries while the shorter staves represent the weaker batteries. This is the third function of a BMS. A good BMS will balance all the batteries so that they reach full charge in about the same time. This might be shown as a barrel that has all of the staves at the same length.
Passive BMS systems contain large resister networks which merely redirect the charging current through the resister network and burn up excess power while the balance of weaker cells are getting to their full recharge voltage level.
Cheap BMS systems do not do this they merely turn the charger off when the first battery nears 3.65 volts. With those systems the battery pack could still be charged with a greater amount of power but there isn't any way these cheap systems will allow that to happen. Thus you may lose as much as 20% of the battery packs full potential capacity for the sake of a few dollars saving when purchasing the BMS system. In motor vehicles that can amount to a big loss of range.
The fourth BMS function concerns protecting and balancing the batteries from over discharging. If the batteries are somehow not balanced so that all of the staves are equal, which a properly engineered BMS system will do, than as the battery is discharged the weakest battery, represented in my illustration by the shortest stave in the barrel, will reach its full discharge shutoff point ahead of the rest of the pack. A good BMS system will keep all the cells balanced so that the weakest cell voltage with a LiFePO4 battery will not go below 2.4 volts while the other batteries are allowed to drain their energy. Similarly, a good BMS system will also keep all the cells balanced in a Lithium Polymer battery so that the weakest cell voltage will not go below 2.8 volts while the other batteries are allowed to drain their energy. A well designed BMS will assure that all of the batteries are close to equal in storing and discharging their energy uniformly. The last function of a good BMS system is monitoring and controlling the temperatures within the cells or the total pack. Many lithium chemistries like Lithium Cobalt can spontaneously burst into flames if they are over charged or discharged. Metal fires are extremely hot and water or even fire fighting foams alone will not extinguish the flames. Of all the lithium chemistries Lithium Iron Phosphate (LiFePO4) is the least volatile and theoretically will not combust. However, extreme heat can damage and shorten the life in all lithium cells. A good BMS system will monitor the temperatures within a pack and either shut the pack down or throttle back the discharge or charging current so that the cells never reach a point of overheating.
There are people who claim that you don't need a BMS system! And, in fact they are right. You only need one if you are concerned about the most available power from the pack along with the health and longevity of the lithium cells that you paid a lot of money for. You will add years to your pack life if you use a good, well designed, BMS system.
In summation there is another saying that applies. “You get what you pay for!” Lithium batteries are expensive and you deserve to get a long battery storage life from every dollar that you spend on both the batteries and the BMS system. A good BMS system will pay for itself several times over the lifetime of your battery pack!