How to choose the golf cart batteries: Lithium Ion OR Lead Acid

Updated by author 23rd May, 2022

lithium ion batteries ｜ golf cart ｜ 48V batteries

*C=Capacity/hour. For example, if C=80Ah/hour, 0.5C=0.5*80Ah/h=40A.

What is Lithium ion/Lead acid

Lithium ion batteries, with origin in the 70’s, are made from a carbon electrode, a metal oxide cathode, and an electrolyte made from a lithium salt in an organic solvent. They produce electricity when the lithium ions move from the electrode(anode) to the cathode through the electrolyte.

Common types of lithium ion batteries are lithium manganese oxide (LiMn2o4) or LMO, lithium nickel manganese cobalt oxide(LiNiMnCoO2) or NMC, lithium iron phosphate (LiFePO4) or LFP, etc. Other types of lithium-ion batteries include lithium polymer battery or LiPo, which uses a polymer electrolyte instead of liquid.

Lead acid batteries have been with mankind the longest among all types of batteries, invented in the 1850’s. They are relatively inexpensive to make and account for about 40% of all battery sales. They are made of pure lead electrode, lead oxide cathode and sulphuric acid. The electricity is produced when water molecules are formed from Hydrogen ions of the acid and oxygen ions of the lead oxide.

Common types of lead acid batteries are flooded lead acid in which the sulphuric acid is free to flow within the casing, and sealed lead acid(in which the electrolyte solution is immobilized), which are further classified as AGM and gel.

Which is better

Lead acid batteries are typically only used at 50% to 70% of their rated capacities with 300~400 times lifespan(2~3 years), while lithium ion batteries can be used to 95%(discharging rate) and be drained completely before charging(all LiFePO4 batteries are deep cycle), and their lifespan can be no more than 5000 times(5~8 years).

As lithium ions are 10~15 times more cycle life than lead acid, most second-hand lithium batteries are still capable to be applied as the golf cart batteries.

*DOD means Depth of Discharge, it shows the discharge capacity from the rated capacity of the battery.

Because of the limitation of sulphuric acid, it is impossible to charge the lead acid batteries much quicker than it used to be(15~20 hours). Lead acid might be able to sustain large current for a moment, yet it is pretty dangerous to charge it for long time. Lithium ions can be charging 4~5 times faster(3~5 hours), which also thanks to the protected board(PCB) and management system(BMS) inside.

You will still have 70% capacity left within 5 years even under everyday-charging condition, unlike lead acid battery that drops 50% or more capacity by less than 3 years. When the battery is not using for long, you don’t need to charge the lithium ion battery every month like lead acid does.

Discharging Performance

Lithium ion delivers a constant amount of power throughout the discharge cycle, unlike lead acid that drops the output with time – Lithium ion battery provides constant speed with 18km/h ~ 30km/h, and the lead acid battery goes with 15km/h ~ 40km/h on golf cart.

However, the drop in voltage in lead acid could be a warning mechanism, which does not obtain with lithium ions that simply stop supplying power without giving a warning(protected by management system).

Actually, lithium ion discharges the same maximum instant current (5~15 times of rated capacity) as lead acid does(5~15 times of the 20hr capacity, also known as CCA), with fast reponse like a quick action of camera flash.

Temperature

When it comes to higher temperatures, lithium ions have a better performance than lead acid, from -20℃ to +60℃, and the discharging efficiency can still get to 70% of the capacity. While lead acid batteries can be charged at or even below 32℃ by colder temperatures with 45% charging efficiency, the discharging temperature is better to be between -15℃ ~ 40℃.

Whichever you choose as golf cart batteries, however, 25℃ is always the best temperature to use the lithium ion batteries or lead acid batteries on the golf cart.

Weight

Lead acid batteries are 5 times heavier than lithium ion batteries, with weight energy density of 50wh/kg ~ 70wh/kg comparing to 200wh/kg ~ 260wh/kg of lithium ions(volume decreases about 30%). That means that four 12V 30Ah lead acid batteries with 40KG as golf cart batteries can be replaced by a 48V 150Ah lithium batteries(appr. 50KG). And that means a much long ride through each charge.

This advantage comes to play in weight sensitive installations like vehicles, e.g. RVs, golf carts, e-bicycles, and robots, where less weight is desirable to increase the range. Even in stationary installations, the less weight of battery may be preferable as any supporting structure do not have to be expensively reinforced to bear payload.

Maintenance

Lithium ion batteries have to be installed firmly, and connected at the right direction and with the designated charger – you can never charge the lithium ion battery with lead acid charger. A multi-meter may be needed to check for the voltage once or twice a year, and these are all you need to do.

Lead acid batteries require regular maintenance(twice or four times a year) topped up with distilled water(15~30ml), and they are installed under ventilated and dry condition. You should charge undervoltage battery by a 0.05C~0.1C current charger for extra 10~16 hours.

Where to use

Both lead acid and lithium ion share the same application and purpose to supply energy as backup power. While the former still plays an important role on industrial energy sector, and the latter deals mostly with residential and portable device.

• Lithium ion batteries:
  1. Backup power(Telecommunications, solar energy storage system, electronic switching system, UPS/ECR, emergency lights and fire alarms, etc)
  2. Main power supply(electric vehicles, electric bicycles, forklifts, automotive guided vehicles, cleaning robots, etc)
  3. Mobile power(mobile phone, power tools, electrical toys, electric starter, transceivers, portable power stations, medical equipment, etc)

• Lead acid batteries:
  1. backup power(UPS, emergency lighting system, telecommunications, electrical equipment, etc)
  2. locomotives starter(automobiles, ships, trains, tanks/armored car, tramcar, etc)
  3. power industry(solar and wind energy systems, petroleum energy system, commercial and industrial equipment, elctronic equipment, etc)

How much exactly

Lead acid is much cheaper than lithium ion, only 1/5 to 1/3 of price of the lithium ions. But that is not the only cost you need to spend on: transportation, installation, maintenance, replacement, disposal, and so on.

For example, using a cost of 500€/KWh for lithium ion battery and 100€/KWh for lead acid battery and 2000€ per installation for both, and 1000€ for transport, total costs are 28,000€ and 78,000€ respectively. Costs per usable kWh per cycle then become 0.18 €/KWh and 0.42 €/KWh respectively.

This shows that lithium batteries are about 2.33 times cheaper to set up and operate, despite the higher initial costs of the former.

Actually, the combined expense for installation, maintenance and replacement totally are 1:6 with lithium ion to lead acid through 10 years.

Why lithium ion?

Golf means Green, Oxygen, Light, and Friendship.

You can play golf game and enjoy the nature at the mean time with fresh air around and quietness all over. You can do exercise, be with your friends, enjoy a man’s nature trail, and watch mobs of foxes, alligators, or birds leisurely.

Lithium means Environmental, Easiness, Efficiency and Equilibrium.

They don’t use sulfation to rob the battery performance, they are much easier to maintain, carry or replace, they run much more longer, stabler, thorougher and quieter, and they protect themselves by intelligent PCB or BMS for better safety and performance.

“I can’t think of a technology that’s more important than lithium ion batteries right now.” Said Tesla chair Robyn Denholm in Clean Energy Council.

Believe it or not, lithium ion batteries are challenging the lead acid batteries market due to their benefits in long run. It may cost more up front, but the extra efficiency means you can potentially spend less per kilowatt-hour(KWh) of capacity over the lifespan of the batteries.

Replacing Lead Acid with Lithium ion

When it comes to the real desire from lead acid to lithium, we actually have a few steps to help:

Compute the depth of discharge or usable power for lead acid batteries, which is about 50%, and extrapolate to the value for lithium ion, which is between 80-100%, to avoid oversizing the lithium ion battery capacity.

For example, using the figures above, an 8 lead acid battery setup with rated capacity of 428Ah at 48V will need to be replaced by 4 units of 3.8 kWh LFP batteries.

You may also have to factor in efficiency, as lead acids have 70% efficiency while LFP’s have 98%.

In addition, you may have to reprogram your existing equipment, which may involve recalibrating your inverters and charge controllers to fit with lithium ion charge and discharge curves.