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.
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.
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.
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.
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.