Golf cart batteries come in a few different varieties. The first thing you will notice is that there are three main system voltages: 36V, 48V, and 72V.
36V Systems
36V systems are generally found in older, lower-cost golf carts. They typically use six 6V batteries connected in series to create a nominal 36V system.
These carts typically have speeds in the 10–14 mph range and work best on relatively flat ground.
48V Systems
48V systems have become the norm in today's golf cart market. Traditionally, these systems use lead-acid batteries, typically configured as either eight 6V batteries or four 12V batteries connected in series to provide the nominal 48V required by the cart.
In recent years, the market has seen a significant increase in 48V and 51.2V nominal Lithium Iron Phosphate (LFP/LiFePO₄) batteries, which have become increasingly prevalent in the golf cart market.
72V Systems
72V systems are generally designed for larger 4–6 passenger carts. These systems can deliver speeds of over 25 mph and provide superior hill-climbing torque.
48V vs. 51.2V LFP Golf Cart Batteries
In this article, we are going to focus on 48V nominal systems, with an emphasis on the differences between traditional 48V battery systems and 51.2V nominal LFP batteries.
Specifications of a 48V Lithium Battery
When selecting a battery, voltage isn't the only key specification you need to consider. Battery performance depends heavily on several important technical specifications.
1. Amp Hours (Ah)
Amp hours are essentially the battery's fuel tank. A 48V 105Ah battery is a common size for many golf cart owners and can provide up to 52 miles of range, depending on the cart, driving conditions, terrain, speed, load, and other factors.
Higher-capacity options, such as 150Ah or 170Ah, are better suited for commercial applications, longer-distance driving, or heavier carts.
2. Continuous Discharge Rate (Amps)
The continuous discharge rating indicates how much current the battery can continuously deliver to the motor.
A standard golf cart typically needs at least a 100A continuous discharge rating. Carts equipped with upgraded aftermarket motor controllers may require 150–200A or more, depending on the specific controller and motor combination.
3. Peak Discharge Rate (Amps)
The peak discharge rating indicates how much current the battery can provide for a short period. This is particularly important during initial acceleration and hill climbing, when the motor can demand significantly more current.
A quality 105Ah battery may be capable of delivering a peak discharge of approximately 400A for 30 seconds or up to 600A for 3 seconds. This additional current allows the cart to accelerate properly and maintain performance when climbing inclines.
Voltage Differences: 48V vs. 51.2V Nominal Voltage
Why are some batteries labeled “48V” while others are labeled “51.2V,” and why is this important?
With Lithium Iron Phosphate (LiFePO₄ or LFP) chemistry, each individual cell has a nominal voltage of 3.2V. To build a battery pack compatible with a standard 48V golf cart system, manufacturers connect cells in series:
A 48V nominal battery typically uses 15 cells in series (15S):
15 × 3.2V = 48.0VA 51.2V nominal battery uses 16 cells in series (16S):
16 × 3.2V = 51.2V
Either configuration can be compatible with standard 48V golf cart motors and speed controllers. The 51.2V configuration is often favored because it provides a slightly higher voltage throughout the battery's discharge cycle. This can help maintain more consistent performance and efficiency as the battery discharges.
Why Is the Difference Important?
The difference between 48V and 51.2V is particularly important when selecting a battery charger.
Because the two battery configurations contain different numbers of cells in series, they require different charging voltages. You must select a charger that is specifically appropriate for the battery's chemistry and series-cell configuration to ensure that the battery can reach a true 100% state of charge.
This is important with lithium batteries because most LFP batteries are made up of multiple cells connected in series. Some battery designs also use multiple parallel strings of cells to increase the overall capacity of the battery pack.
These cells and parallel groups need to be periodically balanced. During normal operation, small differences between individual cells can develop. A properly configured charging system allows the battery's BMS to bring the cells back into balance as the battery approaches a full state of charge.
Once the cells are properly balanced, the battery BMS can establish and maintain its 100% state-of-charge reference, helping ensure that the displayed SOC remains accurate.
If the charger does not provide the correct charging voltage—or if the charging cycle is terminated before the battery reaches the voltage required for balancing and calibration—the battery may never reach a true 100% state of charge. Over time, this can lead to SOC calibration issues, where the percentage displayed by the battery's BMS no longer accurately represents the battery's actual state of charge.
This is one of the reasons that simply finding a charger labeled “48V Lithium” is not enough. You need to verify that the charger's charging voltage and charging profile are compatible with the specific battery you are installing.
Choosing the Right Charger
For example, a charger designed for a conventional 48V LFP battery may not be appropriate for a 51.2V LFP battery if its charging voltage is too low to bring all 16 cells to the voltage required for a full charge and proper balancing.
The typical suggested charging voltage for LFP batteries ranges from approximately 3.5 to 3.65V per cell. Ideally, 3.55–3.60V per cell (VPC) should be used for the Bulk/Boost/Absorption voltage to help reduce stress on the cells and maximize battery life.
For a 15-cell LFP battery with a nominal voltage of 48V, the suggested charging range is:
52.5–54.7V
For a 16-cell LFP battery with a nominal voltage of 51.2V, the suggested charging range is:
56.0–57.6V
If you attempt to charge a 16-cell LFP battery using the charging voltage intended for a 15-cell battery, you can experience problems reaching a true full state of charge. This can result in undercharging, reduced available capacity, and state-of-charge calibration issues.
Victron Energy IP43 48V 13A Charger
One example of a charger that can be used for a 48V LFP golf cart application is the Victron Energy IP43 48V 13A single-output charger.
To properly configure the IP43 charger, you should configure it as follows:
Battery Preset: User Defined
Expert Mode: Enabled
Absorption Voltage: 57.6V
Float Voltage: 55.2V
Temperature Compensation: Disabled
Absorption Duration: Fixed
Absorption Time: 30–45 minutes
Tail Current: 3% of battery capacity
Repeated Absorption: Every 10 days
S.P.E. Toro 720 Battery Charger
Another example of a charger that can be used is the Toro 720 Charger from S.P.E. After reviewing the charger documentation, the only charger profile that should be used with this application is:
Battery Type: IU0U Zenith
The reason for this is that Lithium and other available charging profiles do not use a high enough charging voltage for the battery. In addition, these profiles provide no programming capability for the absorption time.
Without a sufficiently high charging voltage and an appropriate absorption period, the battery may not reach a true 100% state of charge. This can prevent the cells from properly balancing and can eventually result in state-of-charge calibration issues, where the SOC displayed by the battery's BMS no longer accurately reflects the actual state of charge.
Final Considerations When Selecting a Charger
When selecting a charger, don't rely solely on the voltage listed in the product name. Always check the actual charging voltage, charging profile, absorption behavior, and compatibility with the specific battery manufacturer's requirements.
A properly selected and programmed charger is critical to ensure that an LFP battery reaches a true 100% state of charge, allows the cells to balance, and maintains accurate state-of-charge reporting over the life of the battery.
If you need help selecting a battery charger for your Surrette battery product, please don't hesitate to contact us at support@rollsbattery.com
Please include the charger manual or specification sheet, along with the specific Surrette battery model you are planning to use with. We will be happy to review the documentation and provide you with the appropriate charging settings needed to ensure that your battery bank receives a full 100% charge.
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