Grape Solar 100W Basic Kit User Guide

Grape Solar 100W Basic Kit

Basic Wiring Diagram

Basic Kit Facts

This 100 watt panel kit will produce an average of 25 amp-hours per day when used in a 12 volt system. This equates to approx. 300 watt-hours of usable power per day. The production amount will vary seasonally, depending on your location and the panel placement.  For more detailed production estimates, see http://pvwatts.nrel.gov/pvwatts.php .

When your battery is fully charged, you will see very low output from the controller. This is normal, and prevents the battery from being overcharged.

If the battery is discharged below 10.6 volts DC, the controller will no longer function. This is because it is powered by the battery, not the panel. In this case, it is necessary to use an AC-powered trickle charger to bring the battery up to the proper voltage.

System Sizing: Step 1 Determine Consumption

**** To determine the total system size you must first calculate your consumption in Watt hours (Wh) per day.

Lighting:
If you have four 15W LED lights (actual wattage not equivalent wattage) that you plan on running for 8 hours per day, you would take the wattage of each bulb, multiply it by the number of bulbs and multiply that by the number of hours of run time per day.

2 bulbs x 15 W/bulb x 8 hours/day = 240 Wh/day

Pumps and Motors:
If you plan to run a 1 horse power (hp) pump for 1/2 hour per day you would first convert the hp into Watts: 1hp = 745W,  Then multiply that by number of hours of run time per day.

1 pump x 745 W/pump x 0.5 hours/day = 373 Wh/day

Misc. Electronics:
If you want a system to power your laptop for 6 hours per day plus a microwave oven for 10 minutes per day you would first need to determine the wattage of each device.  This information can usually be found on the device or approximated with the help of an internet search. Let’s assume that the laptop consumes 65W and the microwave oven consumes 800W.  Multiply each device’s wattage by its run time and add the two numbers together.

1 laptop x 65 W/laptop x 6 hours/day = 390 Wh/day
1 oven x 800 W/oven x (10/60) hours/day = 134 Wh/day
390 Wh/day + 134 Wh/day = 523 Wh/day

Battery Charging:
If your plan is to keep a battery bank charged, first add up the Amp hour (Ah) capacity of all the batteries in your system. The Ah capacity is usually shown on the side of the battery. For example, an RV with two 80Ah would have a 160Ah battery bank.  For this calculation it doesn’t matter if the batteries are connected in series or parallel. Most batteries can only discharge 50% of their Ah capacity so only 50% of the total Ah rating needs to be fed to them to bring them to full charge. In this case that would be 160 divided by two, equaling 80Ah.  To convert Ah into Watt hours, multiply 80Ah by 12V.

2 batteries/day x 80 Ah/battery x 0.50 x 12 V = 960 Wh/day

Watts vs. Watt hours:
Keep in mind that Watts is an instantaneous power measurement, not to be confused with Watt hours, which is the actual energy consumption. Watts must be multiplied by estimated run time to determine energy consumption. A good analogy would be speed vs. distance. Watts are equivalent to speed, whereas Watt hours would be the distance. In order to determine how many panels are needed you need to know the “distance.”

System Sizing: Step 2 Calculate Panel Count

On an average day, a single 100W panel will produce about 300 Watt hours (Wh) of charge. This figure will vary depending on temperature, brightness and time of sun exposure. In the Summer production will be higher than in the Winter. On bright sunny days the output will be higher than on cloudy days.

A single 100W panel will have an average daily production of:
300 Watt hours (Wh) = 0.30 kilo Watt hours (kWh) = 25 Amp hours (Ah)

After determining your consumption in step one, divide that number by the production of a single panel:

Lighting example:
Two15W LEDs for 8 hours per day

240 Wh / 300 Wh/panel = 0.8 panels = 1 panels

Pumps and Motors example:
One 1hp pump for 1/2 hour per day

373 Wh / 300 Wh/panel = 1.24 panels = 2 panels

Misc. Electronics example:
One 65W laptop for 6 hours and one 800W microwave for 10 minutes, per day

523 Wh / 300 Wh/panel = 1.74 panels = 2 panels

Battery Charging example:
Two 80Ah batteries per day

960 Wh / 300 Wh/panel = 3.2 panels = 4 panels

Area Specific Production:

More accurate panel production estimates can be made by using an online program that takes into account the local climate, latitude, tilt angle and bearing of the panel.
The simulator can be found here: http://rredc.nrel.gov/solar/calculators/PVWATTS/version1

1. Click on your State
2. Click on the city nearest to your location
3. Change the DC rating from 4.0 to 100 (to simulate a single 100W panel)*
4. Change the tilt angle to whatever your panel is tilted at (ideal is equal to your latitude)
5. Confirm that your azimuth is correct (180 degrees, facing South, is optimal)
6. Click “Calculate”

A new page will show a “Results” box. The middle column “AC energy” will show your panel output broken down per each month in Watt hours*. For example, the total Watt hour for an optimally tilted panel for one year of production in Eugene is 106,794Wh. The daily production would be 292Wh.

Please note: PV Watts deals in kW & kWh. If you typed 0.1kW to represent a 100W panel the program would round your input up to 4.0kW. To adjust for this, mentally substitute W for kW. Input your data in Watts (W = 1/1000 of a kW) and know that your output is in Wh, not kWh as shown on the website.

106,794 Wh/yr / 365 days/yr = 292 Wh/day

System Sizing: Step 3 Inverter Sizing

The solar panels put out DC power that is fed through a charge controller onto a battery bank. If you have an application that requires AC power you will need an inverter to take that power off of the battery and turn it into 120V AC.

When selecting an inverter it is important to know the total Wattage of your load. In Step 1 we determined the Watt Hour consumption, but for inverter sizing we can go back to just using Watts, and ignore the time factor.

The GS-100+KIT has two options for inverters, a light 450W modified sine and a heavy 2000W pure sine. Because of the modular design of this kit, other inverters may be used as long as they are compatible with the voltage of the battery bank.

Lighting example:
Four 15W LEDs for 8 hours per day

4 Bulbs x 15 W/bulb = 60 W Use the small 450 W inverter

Pumps and Motors example:
One 1hp pump for 1/2 hour per day

1 pump x 745 W/pump = 745 W Use the larger 2000 W inverter

Misc. Electronics example:
One 65W laptop for 6 hours and one 800W microwave for 10 minutes, per day

1 laptop x 65 W/laptop = 65 W Use the 450 W inverter 1
microwave x 800 W/microwave = 800 W Use the 2000 W inverter
Together = 65 W + 800 W = 865 W Use the 2000 W inverter

Battery Charging example:
Two 80Ah batteries per day

No AC required – No inverter needed

Pure Sine vs. Modified Sine
The 450W inverter option uses what is called a modified sine wave. This means that the output of the inverter looks more like a stair step pattern than the smooth wave shown in the diagram above. Modified Sine is fine for charging small devices but if you plan to use anything that has an AC motor you will need the 2000W inverter with pure sine output. Also, some stereos and musical equipment may emit an unwanted “hum” when powered by a modified sine inverter.

System Sizing: Step 4 Battery Bank Sizing

The GS-100+ Preconfigured Kits do not come with batteries, but will work with most deep cycle batteries. A deep cycle battery is designed to be charged and discharged regularly, unlike standard car batteries that are meant to hold a somewhat constant charge. Deep cycle batteries come in many forms including lead acid, sealed AGM and Lithium Ion. A typical deep cycle battery can discharge about 50% of it’s Amp hour (Ah) capacity.

If you need a battery to store 1200Wh of charge you first need to convert the 1200Wh to Ah by dividing it by 12V (the voltage of a battery) to get 100Ah. Since the battery can only discharge 50% of it’s capacity, you must divide the 100Ah by 50% to get 200Ah. A 200Ah battery bank will store 1200Wh of usable power.

1200 Wh / 12 V = 100 Ah 100 Ah / 0.50 = 200 Ah battery bank

Lighting example:
Four 15W LEDs for 8 hours per day, one day back-up

480 Wh / 12 V = 40 Ah (40 Ah / 0.50) x 1 day = 80 Ah battery bank

Pumps and Motors example:
One 1hp pump for 1/2 hour per day, three day back-up

373 Wh / 12 V = 31 Ah
(31 Ah / 0.50) x 3 days = 187 Ah battery bank

Misc. Electronics example:
One 65W laptop for 6 hours and one 800W microwave for 10 minutes, one week back-up

523 Wh / 12 V = 44 Ah
(44 Ah / 0.50) x 7 days = 616 Ah battery bank

Battery Connections:
Multiple batteries can be connected to each other to increase the Amp Hour storage capacity of your system. Since the charge controller and inverters in the GS-100+KIT are de-signed for 12V systems it is important that multiple 12V batteries are connected in parallel and if your system incorporates 6V batteries they should be connected in series pairs.

Battery Life:
Batteries have a limited life. A battery that is discharged 50% every day will not last as long as a battery that is only discharged 20% every day. Consider this when designing your system.

Mounting Hardware & Additional Accessories

Mounting

This Kit comes with 4x Grape Solar Zippity Feet for easy installation on a variety of materials.

For optimum energy production solar panels should be pointed in the direction of the sun to maximize the surface area that can receive light. Since the sun is a moving target, this is best approximated by pointing the panel to the South (for those of us that live in the Northern hemisphere) at a tilt angle equal to your latitude.

References

• PVWatts Calculator
• Grape Solar – Clean Power. Today.

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