Hawaii Prince Golf Course
Solar Golf Cart Top Pay Back Analysis
Prepared by GreenCarts, LLC
Click to read Field Testing Results in PDF
- Charging Costs when using Wall Charger
- Golf Cart Use
- Energy Consumption $$
- Test Results
- Yearly Savings Sheet
- Prolong Battery Life
- Pay Back Analysis
- EarthCare Solar- Peel N Stick
This cost analysis was prepared using data collected during the two-week trial test at Hawaii Prince Golf Course. This pay back analysis is an estimate based on environmental conditions, use of golf cart, and current utility costs. Actual savings and pay back time may be different from estimates.
Charging Costs when using Wall Charger
A 120-volt battery charger is rated to draw 10 amps of power. The power you use in charging the batteries is measured in kilowatt-hours. The formula is “volts X amps = watts”:
| Energy rating | Multiplying Factor | Rates | |
| Charger | 120 Volts X | 10 Amps = | 1.2 Kilowatts (1200 Watts) |
| Hourly Energy Consumption(KWH) |
1.2 Killowatts X | 1 Hour = | 1.2 Kilowatt Hour |
| HI Utility Rate($0.20) | 1.2 Kilowatts X | $0.20 = | $0.24 per hour of Charging |
It cost $0.24 per hour to charge carts.
Test Results
1. Conventional golf cart – No solar roof: 54 holes
2. Peel and Stick: 72 holes
Test Trial at Hawaii Prince Golf Course
The trial test was conducted under Hawaii Prince Golf Course’s normal business operations, using golf course’s cart, employees, and guests. The test was not modified to produce favorable results.
Golf Cart Use
At the Hawaii Prince Golf Course, Golf Carts are used for one round, 18 holes of golf; then plugged in to charge. Golf Carts may be used again if needed for play.
# of Hours to Recharge Batteries
The golf carts’ battery is depleted approximately 30% after 18 holes of golf.
Golf cart battery takes approximately 5 hours to fully charge a completely depleted battery. Based on cart use, Hawaii Prince Golf Course charges the golf carts for 2 hours to charge a battery that is depleted by 30%:
5 hour-full charge x 33% = 1.65 or approximately 2 hours
Energy Consumption $$
Using the equation and information provided above, Hawaii Prince Golf Course spends approximately $24,192 a year to charge 140 golf carts for two hours every day:
| Energy Consumption | Utility Rate | #Hours Recharging |
#Golf Carts | Days/Year | Recharging Cost / Year |
|
1.2 KW
|
$0.20/KWH
|
2
|
140
|
360
|
$24,192
|
1.2 KW x $0.20 x 2 hours of charging x 140 carts x 360 days in a year = $24,192
Prolong Battery Life
Sulfation is the primary reason that batteries need to be replaced. Solar panels provide a constant charge to the battery bank preventing the crystallization of lead sulfate and can double battery life.
Batteries cost $600 per golf cart.
$600 x 140 golf carts= $84,000
Batteries at the Hawaii Prince Golf Course are regularly replaced every three years.
Over a period of three years, the golf course spends $28,000 a year:
$84,000 ÷ 3 years = $28,000
A solar golf cart roof will extend the battery life by two years.
By installing a solar top, battery life is extended to five years.
Over a period of five years, the golf course spends $16,800 a year:
$84,000 ÷ 5 years = $16,800
Hawaii Prince Golf Course will save $11,200 a year on battery costs.
$28,000 – $16,800 = $11,200 yearly savings.
If the batteries are purchased with the solar panels they also qualify for a 30% Federal Tax Credit. This also significantly reduces battery costs.
$84,000 x 30% Federal Tax Credit= $25,200
Hawaii Prince Golf Course: Peel N Stick Solar Roof Kit Payback Analysis
This payback analysis shows the total cost of 140 solar tops.
The tops are priced at $1,600
Pay Back Analysis
After the seventh year, the system has paid itself off!
Hawaii Prince Golf Course will continue to
Save a total of $22,087 every year!
Payback without Tax Credit
$1,600 x 140= $224,000
$224,000 ÷ $22,087 = 10 years
| Total Cost of Solar tops | ($1,600 x 140) = $224,000 |
| $224,000 x 30% = | |
| 30% Federal Tax Credit | $67,200 |
| Cost after Tax Credit | $156,800 |
| Yearly Energy and Battery Savings | $10,887 + $11,200 = $22,087 |
| Cost ÷ Yearly Savings | $156,800 ÷ $22,087 = 7 years |
Yearly Savings Sheet
| # of Holes Golf Cart can Travel | Day1: # of Holes Traveled | # of Holes Remaining | Battery Depletion/ Hours to Recharge (% are based on 5 hours to reach full charge) | Cost per Recharge (one cart) |
Cost (140 Carts) |
Yearly Cost (360 days) |
Yearly Savings |
| Battery 54 Holes |
18 | 36 | 33% depleted 2 hours to Recharge | $0.24/hr x 2 hrs =$0.48/day to recharge one cart | $67.20 / day to charge 140 carts for 2 hours | $24,192 / year to charge 140 carts for 2 hours | N/A |
| Battery + Peel N Stick 72 Holes |
18 | 54 | 22% depleted 1.1 hours to Recharge | $0.24/ hr x 1.1 hr = $0.26/day to recharge one cart | $36.96 / day to charge 140 carts for 1.1 hours | $13,305/ year to charge 140 carts for 2 hours. | $24,192 – $13,305=$10,887 |
