What’s the Fuss About Solar ?!
Howdy !
Looking at the questions asked about the solar power articles that I’ve done for rv magazines and on this BLOG it seems to me that solar power is somewhat misunderstood because we don’t have the information to provide real answers.
Here is the most common question:
Q. What does it cost to put solar on a RV ??
A. How much have ya got ?!
This is the most common question and the hardest to answer because there is no real way to answer it. It’s kinda like the chicken or the egg type question. The first thing you must know before we can even begin to get to the bottom of this one is – how much power do you need ? We start by completing the power sizing chart to determine how much power we use. To make this work we really do need to add-up ALL the devices we have in the RV, both 12-Volt DC and 120-Volt AC. Let’s assume that we are designing a solar driven power system of solar panels, an inverter for 120 Volts AC, a battery bank and the needed controllers, cables and so on to make it all work.
Enter the Wattage marked on the ALL electrical items first then mutilply by the number of hours in a 4-hour “day” you use that device. For example, if you use the water pump for a total of 1/2-hour a day then your total might look like 40-watts X 30 Min – 20-Watts of power used for the pump. Modify the chart to fit the devices you use, like the satellite TV and DVR. Don’t forget the little things like the electrict heater rod in the water heater, the carbon monixicide alarm and so on.
The resulting amp-hours total will amaze you ! The real shocker will be when you have multiplied that AC devices wattage by 10 to reflect the power loss from using an inverter system. OK, here is the chart –
Power sizing chart
DC Devices 12 Volts Watts X Hours/Day = Daily Watt Hours
AM/FM radio 12 Watts ___________ _____________
CB radio 15 Watts ___________ _____________
Cassette/CD player 30 Watts ___________ _____________
TV black/white 18 Watts ___________ _____________
TV 9″ Color 40 Watts ___________ _____________
TV 14″ Color 84 Watts ___________ _____________
Incandescent light #1141 18 Watts ___________ _____________
Fluorescent – 1 tube 13 Watts ___________ _____________
Fluorescent – 2 tube 26 Watts ___________ _____________
Water pump 8 – 12 Gal/day 24 Watts ___________ _____________
Water pump 16 -24 Gal/day 48 Watts ___________ _____________
Forced air furnace 48-96 Watts ___________ _____________
Fantastic fan 120 Watts ___________ _____________
Bathroom fan 18 Watts ___________ _____________
Range hood fan 144 Watts ___________ _____________
The AC appliances listed below require the use of an inverter. The AC Watts have been multiplied by a factor of 10 to show
the DC watts usage from the battery.
AC Devices 120 Volts Watts X Hours/Day = Daily Watt Hours
Microwave oven 1650 Watts ____________ _____________
Blender 198 Watts ____________ _____________
Vacuum cleaner 80 Watts ____________ _____________
Computer 55 Watts ____________ _____________
14″ Color monitor 100 Watts ____________ _____________
Laser printer 1200 Watts ____________ _____________
Ink jet printer 35 Watts ____________ _____________
Electric clock 4 Watts ____________ _____________
Hair dryer 1500 Watts ____________ _____________
VCR 30 Watts ____________ _____________
Sub total of daily watt/hours ___________
Multiply subtotal by .10 for battery inefficiencies ___________
Multiply subtotal by .4 if you leave panels flat ___________
Multiply subtotal by .4 and subtract if you plan to
track the sun with your panels ___________
Adjusted daily watt/hours – – – – – – – – – – – ___________
Divide by the average peak sun hours per day for
your area. – – – – – – – – – – – – – – – – – – – __________
Add up the total watts used per day – – – – – ___________
Total array watts needed – – – – – – – – – – – – ___________
Ok, I’m going to leave you to figure our YOUR power needs for the normal operation of YOUR RV. Do the homework and we will continue the system design next week when we have some real numbers to work with.
Later – – –
The Old Ranger