The Don Rowe Blog
Hot Tubs—‘Hot’ Cuz They’re Powered By The Sun!
Power inverters—their uses are immense and they remain probably one of the most ingenious inventions, ever! One example for power-inverter usage deals with hand-held inverters used to convert DC battery energy into AC electricity for small electronics used during U.S. military reconnaissance in foreign countries. Inverters are also used aboard NASA space-craft to enable electrical equipment to seamlessly operate, via AC electricity. Or how about inverters that are used to power lighting and instruction equipment for schools in 3rd-World countries? It becomes very obvious that inverters truly do make the world go ‘round!
Chances are good that anyone reading this isn’t in a war-zone or hundreds of miles into space or teaching impoverished children in Africa how to read; but as everyday citizens, we still value and fully appreciate what power inverters do for us at home, right here in the good ol’ USA! At times, power-inverters are an absolute necessity such as during a power-outage to enable electronics and appliances to operate until the power-grid can kick in once again. But then, there are those times where power inverters can be used for strictly pleasurable and indulging reasons—one of those reasons being solar-powered hot tubs!
Besides creating affordable electricity for your home, solar panels can heat your hot-tub. Solar panels will convert upwards of 22% of the sun’s energy through the use of photovoltaic, or PV, cells. These amazing little guys collect the sun’s energy and convert it into electricity. But before that electricity can be used, it’s converted into AC form, or alternating current. Now, take a wild guess as to what converts the sun’s energy into the AC electricity—if you guessed power (solar) inverters, you’re right!
The Solar Hot Tub:
Are you interested in converting your electric hot-tub to a solar-powered version? It can be done! If you are serious about that type of conversion, there are hot tub solar water heaters which include all the necessary components to make your hot tub entirely solar powered. You can save a bundle of cash by eliminating the high-cost of heating your hot tub via the power-grid! Here are the basic steps involved with turning your hot tub into a solar-consumer rather than a grid-consumer—the savings on your electric bill will be noticeable!
It’s going to be assumed that your hot tub has already been positioned to receive the maximum amount of direct sunlight. Additionally, covering the water with a transparent plastic cover will work wonders with heating up the water during the day and keeping the water warm at night. This type of direct heating will allow you to use a smaller heater which boils down to using a smaller battery bank and solar array.
A Few Basic Steps To Get The Conversion Rolling:
As with any project, have all the necessary equipment available. This would include 1) semi-transparent plastic cover 2) solar panels 3) transmission wires 4) battery bank 5) battery cables 6) charge controller and 7) Solar inverter.
Step 1: Do the Calculations ~
The power draw of the heater will need to be calculated and it’s easy to determine. Simply take the heater’s current rating and multiply that by the voltage at which it runs. So: current rating X voltage = power draw.
The next calculation will involve estimating the hours each day that the heater needs to run to effectively warm the water. Whatever number that might be, multiply that by the power-draw you calculated in Step #1, above. This will give you the number of watt hours the batteries will be required to supply. So: # hours of heater run-time X power-draw = # of watt hours. Online calculators can help you determine the number of panels and batteries required.
Step 2: Positioning The Solar Array ~
As would be logically expected, the solar array needs to be positioned in full sun, as much possible. It should also be in close proximity of the hot tub which will reduce the wiring that will be run between the panels and the battery bank. As a result, transmission loss will be minimized. You can reduce the number of solar panels you need by charging a battery bank and running the heater off the batteries.
Step 3: Setting Up The Battery Bank ~
The battery bank needs to be located in an enclosed, yet well-ventilated area. It needs to, also, be as close to the hot tub as possible. The operating voltage and the volume of electricity the batteries can collect will most definitely determine the size of the bank as well as the arrangement of the batteries. If the hot tub has been situated on a raised platform, storage space for the batteries can be configured underneath.
Step 4: The Charge Controller ~
The controller is vital since its function is to provide a seamlessly smooth charging current to the batteries. Additionally, the controller 1) ensures the batteries do not overcharge and it 2) guards the solar panels by preventing electricity from flowing backward from the batteries.
Here, you will run the wires from the panels to the charge controller and then unite the controller to the battery bank with battery cables.
Step 5: Ahhh—The Inverter ~
Finally we get to the solar inverter! You’ll connect the charge controller to an inverter which, of course, will make this all happen. The solar inverter’s ‘job description’ is to convert the DC current from the batteries into AC power which will enable the hot tub to operate at the appropriate voltage. If you’re not familiar with inverters, your best bet is to seek the professional advice from an inverter expert. In any case, the inverter must be correctly grounded; and instructions need to be followed to a “T”.
Make sure the solar panels have ample time to entirely charge the battery bank before the hot tub’s heater is plugged into the power inverter.
Considering the fact that a hot tub typically adds anywhere from $60 to $90 a month to your electricity bill, it only makes sense to go solar! I’m aware of this since my neighbor has complained about his electric bill expanding by almost $100 a month due to his family’s hot-tub usage. His hot tub is ‘going solar’ by this spring; and due to his utility savings, the conversion will, most definitely, pay for itself!