PowerOptimal SOL-PVE-SYSTEM Elon 100 Solar PV Water Heating unit User Manual

Power Optimal SOL-PVE-SYSTEM Elon 100 Solar PV Water Heating unit User Manual

SAFETY WARNING

• Installation of the Elon® 100 should ONLY be performed by an electrical contractor registered with the Department of Labour (the so-called “wireman’s licence”) and strictly according to the installation instructions in this manual. The electrician should provide you with a Certificate of Compliance (CoC) once installation is completed.
• We strongly recommend that you use a reputable and experienced solar photovoltaic (PV) system installer to install your solar PV modules.
• Solar PV modules exposed to the sun are live (i.e. will produce electricity) and can give an electric shock. Special care should be taken and only trained solar PV installers should install the modules.
• Do not attempt to alter or service the electrical installation, or open the Elon® 100 unit or controller for any purpose.
• Use the Elon® 100 only for its intended purpose.
• Always make sure that every wiring connection is properly tightened.
• Do not earth either of the solar module wires (but do earth the frames).
• All installation wiring should be at least 2.5mm².
• Avoid coiling, since DC switching can create damaging spikes.
• Keep all wires as short as possible.

Refer to the Power Optimal website for the following:

Elon® 100 Installation Guide & Quick Reference User Guide| www.poweroptimal.com/manuals
---|---
Online User Instructions Video| www.poweroptimal.com/elon100

Online Elon® Basic Training Course| https://moolmaninstitute.com/p/eloncourse

Introduction

Thank you for buying the Power Optimal Elon® 100 solar PV water heating unit! You can look forward to many years of savings and free energy from the sun.

System overview

The Power Optimal Elon® 100 operates on a very simple principle: it enables you to connect solar PV modules directly to a standard geyser with alternating current (AC) heating element and AC thermostat, with no need for an inverter. It uses the water in your geyser as a battery to store solar energy in the form of heat.

You can connect the system completely off-grid or connect it to your existing grid AC power supply. Connecting the system to the existing grid supply allows for grid power backup in case of cloudy / overcast days, or where you use more hot water than your solar PV array can generate.

Note: the system is designed in such a way that there is no possibility of solar array produced electricity feeding back into the grid. For municipal registration purposes it  is classified as “off-grid”.

Below is a simplified layout of the main components of the water heating system.

An array of solar modules (a string of 3 to 6 solar modules connected in series, or two parallel strings of 4, 5 or 6 solar modules each) is connected to the Elon® 100. Grid electricity is also connected to the Elon® 100.

The Elon® 100 is connected to the geyser element and thermostat.

When the solar modules are producing electricity, the Elon® 100 feeds this into the geyser element to heat water, until the water reaches the temperature setting on the thermostat.

The Elon® 100 controller dial setting (see Section 2.3) will determine if or when the Elon® 100 will boost the water heating with grid electricit

Main system components

The main components of the system are as follows:

• Solar modules with struts, brackets and cabling
• PowerOptimal Elon® unit with controller
• Existing or new water heater or geyser (hot water tank with AC heating element and AC thermostat)
• Isolators for grid and solar connections

Deciding on size of Elon® system (basic guide)

The table below provides a basic guide to selecting the size of your Elon® system based on number of people in the household and/or hot water use. The Installation Manual (which you can download from www.poweroptimal.com/manuals) contains a more detailed guide.

HOW MANY SOLAR PV MODULES DO I NEED?

Solar PV array size (kWp )| **Showers per day*| 50%+ of daily hot water use provided for how many people?| How many people off-grid for hot water?| Typical number of solar PV modules
---|---|---|---|---
1 – 1.2| **| | | 2 – 3 modules
1.2 – 1.6| ~~ ~~| | | 3 – 4 modules
1.5 – 2| | | | 4 – 5 modules
2.4 – 3.2 (two parallel PV strings)| | | | 4 – 5 modules
3 – 4 (two parallel PV strings)| | | | 8 – 10 modules

• 6-minute showers at 40 ºC with 8 litre/min (low-flow) showerheads

WHAT SIZE GEYSER ELEMENT IS THE BEST MATCH?

• Second choice element size would reduce efficiency by 10 – 20%.

Operation

Instruction video: www.poweroptimal.com/elon100

Refer to our easy to understand instruction video on how to use the Elon 100.

Elon® 100 controller

Your Elon® 100 has a controller that is typically installed next to your DB (distribution board). The controller has two main functions:

1. INDICATING ACTIVITY AND STATUS:
   Indicating heating activity and status through the mains (red) & solar (green) indicator lights (Section 2.2)

2. CONTROL TIMING:
   Setting the timing on the control dial (Section 2.3)
   

Mains and solar indicator light

The Mains & solar indicator lights indicate the following conditions:

Green light ON| Geyser on temperature

Green light flashing| Heating with solar

Red light ON| Mains power available (power to Elon® unit on)

Red light flashing| Heating with mains

Both lights ON| Geyser is on temperature. Mains power available (mains power to Elon® unit on)

Red light ON & Green light flashing| Heating with solar. Mains power available (mains power to Elon® unit on)

Red & Green light flashing fast| Isolation fault (contact electrician)

Both lights OFF| No power to unit (for example: no sun plus a power failure, or no sun plus geyser breaker at DB board is switched off) OR supply voltage outside specifications

Control dial settings

Dial Setting| Time on Mains| Time on Solar| 24-Hour Clock
---|---|---|---
MAINS ONLY| 24 hr| Never|
1| 12:00 to 08:00| 08:00 to 12:00|
2| 14:30 to 05:30| 05:30 to 14:30| **
3| 17:00 to 03:00| 03:00 to 17:00| **
SOLAR ONLY| Never| 24 hr|

• Times are approximate – will vary slightly with season and location

Think of the water in your geyser as a battery that can store energy in the form of hot water. To charge the battery (or heat the water) with solar energy during the day, it must cool down a bit in the morning. In other words, the water must be below its setpoint temperature by the time the sun comes up.

The Elon® achieves this by switching off mains power at some time in the morning, while you are still using hot water from the geyser. The table above indicates approximate switching times for different dial settings.

When the control dial is set to “MAINS   ONLY”, your geyser will use mains power 24 hours a day (in other words, it will never switch to solar power). The geyser will behave the same as any standard geyser. This setting is sometimes useful when you are using a lot of hot water or you have a few very cloudy days in a row, or you have a lot of guests.

If you only use hot water early morning and in the evenings, you can set it close to “Solar only” to benefit from a longer solar energy heating period (and save more money).

When the control dial is set to “SOLAR ONLY”, the Elon® 100 will ONLY use solar power to heat water.

If you set the control dial to “SOLAR ONLY”, you can increase the geyser thermostat temperature to 60 ºC to get maximum benefit from your solar array installation. We do not recommend setting the thermostat temperature above 60 °C. Remember to reduce the thermostat temperature again if you reduce the efficiency setting.

Warning: Do not set thermostat temperature above 65 ºC due to increased scalding risk. Be careful when opening hot water taps located close to your geyser. You can install a thermostatic mixing valve to reduce the risk of scalding – ask your plumber.

Please note: DO NOT install a separate timer on the AC side to try and regulate mains power use. Use only the Elon’s control dial to control mains power use. If you install a second timer, it will work at cross-purposes with the Elon and you will reduce performance and hot water availability

Holiday settings

What setting should I use when I go on holiday?

You can either switch off both solar and mains power OR you can switch off mains power.

return, and it will cost you nothing. It will also prevent Legionella growth in your geyser.
Both Mains & Solar power off| Turn dial to MAINS ONLY and switch off geyser at distribution board| Remember to switch system on when you return.

How to maximise your savings

Control dial
The best way to maximise your savings is to set the Elon® control dial to “SOLAR ONLY”. This will ensure that the unit will never use grid (mains) power for heating water. You can still boost with mains power (for example on a cloudy day) by turning the dial to “MAINS ONLY” if needed.

However, the “SOLAR ONLY” setting will only be feasible if you have enough solar PV modules for your household (see the table in Section 1.3 above).

For most people, setting the dial at “3” will yield the most savings whilst maintaining hot water availability mornings and evenings.

Please note: The water in your geyser should be heated to 60 °C at least once a week to prevent Legionella bacterial growth1 . If you have heavily overcast weather for more than a week on the SOLAR ONLY setting, turn the dial clockwise outside of the SOLAR ONLY zone for a day in order to supplement the solar water heating with grid electricity to reach the thermostat temperature setting.

When is the best time to shower?
If the control dial is set to “SOLAR ONLY”, it is best for people in the householdto shower either in the morning or in the evening, but not both. (If you shower in the evening, cold water will mix with the remaining warm water overnight, and you will have cold water the next morning. If you do not shower again in the morning, the water will be heated during the day.)

If the control dial is set to any setting outside “SOLAR ONLY” or “MAINS ONLY”, it is best to shower in the morning for maximum savings.

General hot water energy saving tips

• Shower, don’t bath
• Install water-saving / low flow shower heads (these also save energy because of reduced hot water use!)
• Reduce shower duration
• Check that your geyser is well insulated

South Africa is a water-scarce country – reducing hot water use saves both energy and water!

Maintenance

The Elon® 100 has been designed to last for a very long time and has no moving parts aside from three electrical relays. No maintenance is required on the Elon® 100.

Solar PV module maintenance

It is recommended that a qualified electrician inspect your solar PV installation at least once a year.

1. At least once a week, check whether the indicator lights are flashing rapidly. (This indicates an isolation fault – call your electrician.)
2. Perform regular visual checks (at least once a year). Check for soiling or any visible damage to any of the modules.
3. If the modules have been soiled by dirt, dust, debris, bird droppings or any other materials, use water only and a sponge or soft cloth to clean them. Do the cleaning early in the morning or late in the afternoon, as the modules are hot during the day. Avoid using a water jet that may leave streaks on the modules.
4. Visually inspect cables for any degradation or loose fittings.
5. Look for any shading problems, such as trees that may have grown.
6. An electrician can check solar power production on a sunny day to ensure that the system is still producing power at expected levels. A thermal imaging camera can be used to inspect modules for hot spots.
7. Follow any specific maintenance instructions from the solar PV module manufacturer.

What to expect in terms of performance

Hot water production

Heating water takes a LOT of energy. A household geyser can use up to 40% of a house’s electricity. Heating a single 200 litre geyser from 15 °C to 60 °C will use over 10 kWh. This is about the same amount of energy burnt by a person running a distance of over 100 km at 10 km/hr, or enough energy to watch more than 120 hours of TV2 .

The more solar panels you have on your roof, the faster the Elon® 100 system will heat your water. Typically, the number of panels has been selected to heat water over most of the sunlight hours (from morning to afternoon). This will be slower than heating water using grid electricity. So you can expect a gradual temperature rise from morning to afternoon.

As one would expect, hot water production increases with increase in number of solar panels. Keep in mind that these numbers are averages over the year. This means that you should expect a lower number in winter and a higher number in summer.

Impact of location and seasons

The amount of energy from the sun depends on your location, the time of year as well as the orientation of your solar panels. The best direction for panels in South Africa is to face north, at an angle of about 25 to 35° from horizontal.

Although Gauteng (Johannesburg / Pretoria) & Cape Town may seem quite similar in terms of total solar energy per year, Cape Town has winter rainfall and Gauteng has summer rainfall. This leads to Cape Town having much lower solar electricity production than Gauteng in winter (see the below graph).

Payback period

As can be seen from the graph above, payback period decreases as number of solar panels increases, and is also different for Johannesburg, Cape Town and Durban3 .

The reason that payback period improves (decreases) as number of solar panels increases, is because there are some fixed costs (such as engineering design & safety components) and some costs that do not scale linearly with array size (such as labour, wiring, mounting kit costs, etc.)

Troubleshooting

Troubleshooting Guide for Users

Below you can find the same information with some further detail in table format. If you cannot resolve the problem using the diagram or table, please contact your installer.

day c. Dirty solar modules d. Mains circuit breaker has tripped e. Thermostat connection or thermostat defective| a. Turn control dial clockwise (2.3) OR Reduce hot water use (2.5) OR Add additional solar modules to your solar installation (first consult with your installer) b. See a. above c. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1) d. Check mains circuit breaker e. Call electrician for inspection
Water temperature remains low after turning dial to “MAINS ONLY”. (Note: the red LED light should start flashing once dial is turned to “MAINS ONLY”, indicating that the water is being heated.)| a. Sufficient time has not been provided for water to be heated after dial has been turned b. It is a cloudy day and there is a mains power failure c. There is an electrical fault or the Elon® 100 is defective d. Thermostat connection or thermostat or element defective| a. Wait for 2 hours after turning the dial to “MAINS ONLY”. b. You will have to wait until either the solar or grid power returns to heat the water c. Check if the mains light on the Elon® 100 controller starts flashing after you turn the dial to “MAINS ONLY”. If it does not and your water remains cold, call your electrician to inspect the installation for any electrical fault. d. Call electrician for inspection
Water temperature too high| a. Thermostat temperature setting is high and you are using hot water from a tap close to the geyser b. Thermostat connection or thermostat defective| a. Reduce thermostat temperature set point OR Open the cold water tap first OR Install a thermostatic mixing valve b. Call electrician for inspection.
Hot water production is lower than it used to be| a. Dirty solar modules b. Trees / plants have grown and are causing shaded areas on solar modules c. Damage to solar modules| a. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1) b. Trim trees and plants c. Installer or electrician should test solar array power production in sunny conditions and compare with specifications. If one or more modules are damaged and they are still under warranty, contact manufacturer for replacement
Both indicator lights off| a. There is a power failure and it is overcast or night-time b. Geyser breaker at DB board switched off and it is overcast or night-time c. Mains power is over- or under-voltage| a. Wait until power or sun returns and check if any indicator light comes on. b. Switch on breaker at DB board. c. If actions in a. and b. above do not resolve the issue, call your electrician.
Red or green indicator light flashing very fast| a. Isolation fault| a. Please call your electrician.

Troubleshooting Guide for Electricians

NOTE: This Troubleshooting Guide is intended for electricians and not general users. Users should please refer to Section 5.1.

• The red mains LED will only start functioning once stable mains voltage between 160 and 260 V AC is present for more than 4 minutes. (In other words, the Elon® will only allow mains power to the element 4 minutes after mains connection or switch-on.)
• Solar power is only recognised 40 seconds after active solar panels are connected to Elon®.
• An open thermostat (water at correct temperature) measures between 11 and 14 V DC across the “thermostat” terminals on the Elon®. Polarity across these terminals is not important.
• A closed thermostat (cold water) measures 0 V across the “thermostat” terminals on the Elon®.
• How to switch on solar power to element: With enough solar energy (check at solar terminals), solar power will be routed to the element within 15 seconds after the thermostat closes and the controller dial is set to “SOLAR ONLY”. A green flashing LED indicates this condition.
• How to switch on mains power to element: Turn control dial to “MAINS ONLY” and, if the thermostat is closed, mains power will be directed to the element indicated by a red flashing LED.
• Note: Once the dial has been turned to “MAINS ONLY”, it will complete a full mains heating cycle (until the thermostat opens). Turning the control back to “SOLAR ONLY” at this point will not immediately switch the unit back to solar power. It will only switch back again after the mains heating cycle is completed (i.e. the thermostat opens) and the thermostat then closes again. You can finish the mains heating cycle faster by reducing the thermostat temperature setting until the thermostat opens. Test solar power first.
• Fast flashing red / green LEDs indicate a short between a PV (photovoltaic) lead and earth – this condition prevents solar power to the element.

Troubleshooting Steps

1. Confirm correct wiring and polarity to Elon®. Also confirm test meter wires are connected correctly, black to common!
2. Confirm correct voltages and currents of all connections through the following steps:
   • Confirm open / closed thermostat voltages (11 – 14 V DC open, 0 V DC closed).
   • Confirm controller wire is connected properly. The connections should “click” into place and appropriate LEDs should indicate (be active).
   • With solar power to element switched on (green LED flashing), nfirm same DC voltage to element as measured at solar terminals.
   • With DC clamp meter confirm that there is an active current through element.
   • With mains power to element switched on (red LED flashing), confirm same AC voltage to element as measured at mains terminals (should be approx. 230V AC).
   • With AC clamp meter confirm active current through element of between 9 and 18 Amps depending on element rating.
3. If you used a test controller for troubleshooting, remember to plug the wire from the installed controller back into the Elon® and check functioning. Set thermostat back to original setting.

Appendix A. IEC/SANS and EMC Test Certificates: Elon® 100

Appendix B. Warranty

If the Power Optimal Elon® 100 (“the Product”) is found to be defective, you will be entitled to a repair or replacement within 2 (two) years of the date of delivery of the Product to you. Please keep your receipt as proof of purchase. If you are a consumer as defined in the Consumer Protection Act No. 68 of 2008 (“the CPA”), you will be entitled to such remedies as are made available under the CPA in relation to the return of goods.

Power Optimal will not have any liability or obligation to you where the Product has been subjected to abuse, misuse, improper use, improper testing, negligence, accident, alteration, tampering or repair by a third party.

To the maximum extent permitted by applicable law, in no event shall PowerOptimal be liable for any special, incidental, indirect, or consequential damages whatsoever, including, without limitation, damages for loss of business profits or business interruption, arising out of the use or inability to use this product.

Please note that this unit must be installed by an electrical contractor registered with the Department of Labour. Failure to do so may invalidate this warranty. Please keep the CoC (Certificate of Compliance) issued by the electrical contractor on completion of the installation.

Appendix C. Terminology

AC Alternating Current – an electric current that reverses its direction many times a second at regular intervals, with voltage typically varying in the form of a sine wave.
CoC Certificate of Compliance – to be issued by the electrician installing your Elon® 100 system
CPA Consumer Protection Act No. 68 of 2008
DB Distribution board – the main electrical distribution board / panel in your home, containing circuit breakers and switches.
DC Direct Current – an electric current flowing in one direction only. Solar PVmodules produce direct current electricity. Geyser South African term for a water heater IEC International Electrotechnical Commission
kWh A derived unit of energy equal to 3.6 MJ (megajoules). The amount of energy used by 1 kW electrical device over a period of 1 hour.
Wp or Wp The peak power rating in kilowatt (kW) or watt (W) of a solar module or array – i.e. the output power achieved under full solar radiation. This is usually reported at STC and NOCT.
PV Photovoltaic – referring to the production of electric current at the junction of two materials exposed to light.
SANS South African National Standards

© Power Optimal (Pty) Ltd 2022. The content of this document is confidential and  all rights to the intellectual property and/or information contained herein remain vested in Power Optimal, except if otherwise agreed in writing.

Version number: 2.15
Version date: 2022/06/28
Enquiries: info@poweroptimal.com
Address: Postnet Suite 21 Private Bag X21 Tyger Valley 7536

Patented: GB2583814, ZA2019/02129
Patents pending: PCT/IB2021/050542, GB2206504.9

References

• NSF International: Download
• Demand Response - Eskom
• PowerOptimal Elon® 100 user instructions video (8:13) - PowerOptimal - the Future of Energy
• Moolman Institute of Technology Commercialization | The Moolman
• PowerOptimal Elon® Solar PV Water Heater Basic Training Course | The

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