We, at Alta Vision Solar, are dedicated to providing the Sri Lankan residences and industries with tailor-made solar solutions that are invented with the best solar PV equipment in the world, with the unrivaled engineering expertise.

Considering the daily issues occurring due to long power cuts, increased electricity bills, environmental concerns, etc., team Alta Vision came up with an effective solution; Alta Vision Solar Powerwall, for our valued residential and industrial customers. Alta Vision Solar Powerwall offers Off-Grid/Hybrid Solar PV Energy solutions for users to go grid-independent. The solution is reliable, scalable, high-quality, and perfectly matches the existing energy demand in the country.

What is Off-Grid/Hybrid Solar PV Energy?

The term ‘Off-Grid’ means that you're no longer relying on a utility for power, which is a good solution when the grid connectivity is unstable.

Off-Grid solar PV systems all operate on the same fundamental principles. Solar panels use the photovoltaic (PV) effect to convert solar energy or sunlight into DC power. The DC power will be stored in a battery which can then be utilized to power households or business appliances.

Alta Vision Solar Powerwall

Alta Vision Solar Powerwall is a package delivered to you with a combination of solar panels, inverters, and batteries of Growatt, Rosen, and GoodWe brands.

Installing Alta Vision Solar Powerwall at your premises will provide you with the below benefits.

• Backup power from the battery when grid connectivity is unavailable.
• The capability of powering a standard house with appliances.
• The capability of charging the batteries with grid power or solar panels.
• Automatic transfer from the grid to battery backup mode during a grid outage.
• The hybrid option allows excess power to be exported to the national grid and get paid for that!

Need to invest in Alta Vision Solar Powerwall? You might have tons of questions whirling around your head now. Hence we have put together some frequently asked questions below for your reference.

Panels and Inverter

1. Will a system with 3kW capacity be adequate to power an air conditioner along with a few other appliances such as a refrigerator, router, laptop, and fan?
   Yes, it is possible. But, high power-consuming appliances like air conditioners, motors, heaters, etc. are not recommended to be used under battery mode as it would drain the battery quickly in a short time.
2. How many solar panels should be installed?
   For a 3kW system, 6 solar panels are required. It depends on the wattage of the solar panel.
3. If we already have solar panels, can we connect some of them to this system?
   Yes, it is possible. But connecting the existing panels to the new system might void the warranty from the previous vendor, and also, it is difficult to give a warranty from our end as well. Also, we need to technically match the MPPT voltage range of the inverter from the existing panels.
4. Are these pure sine wave inverters?
   Yes, pure sine wave inverters.
5. What is the difference between offgrid and hybrid options?
   Using an offgrid inverter, you cannot export power to the grid. You can only power up your premises. If you install a hybrid inverter, you have the option of exporting power to the grid as well.
6. Is there a means of monitoring inverter output, temperature, solar output, consumption etc. (from a mobile app/web interface, perhaps?)
   Yes, Growatt and GoodWe both have those features.
7. Does GoodWe inverter have an inbuilt wifi module?
   Yes.
8. If we install the inverter in a living area, is it too noisy? If so, is it possible to install the system outside the house?
   There will be fans working for cooling, which will make a little noise. However, mounting outdoors is not the best option since the Inverter and battery need to be sheltered from rain and sun with good ventilation.
9. Quality and durability-wise, which inverter brand is better?
   Both inverters are good. GoodWe has brand recognition in the market.
10. Hybrid inverter can be configured to first charge the battery, and then when it’s fully charged, can it feed the grid?
    Yes.

Battery

11. Can the batteries be charged from the main AC supply or do we need to always install solar panels?
    Installing solar panels is optional. You can charge the batteries using the main supply. When the electricity supply is there, you can charge the batteries and use them when the supply is interrupted.
12. If we are to fully charge the battery using the grid, how much power will it consume?
    It consumes 5 units (kWh) to fully charge a 48V, 100Ah battery.
13. If we say there is a blackout at night in a 200-unit-consuming house, for how many hours will it last with the option that has 5kWh battery capacity?
    The battery has 5 units (kWh) storage capacity. Depending on the load, the number of hours will be decided. e.g., If 1 kW continuous load, then 5 hours approx.
14. During the nighttime, can we configure to consume from the battery first and then move to consume from the grid (on days where there would be no power cuts)?
    Yes, that is possible.
15. As per my knowledge, the drain level of the batteries should be kept at an ideal place so the batteries would last long. Is there any mechanism placed in the system to do this in case we use the battery pack for the whole day during a power cut?
    We can set the parameters via the Battery Management System (BMS) to control the charge and discharge behavior of the battery. The duration of the battery usage depends on the loads powered using the batteries.
16. Are there any safety measures taken to not to drain the battery over the safe limit during a power cut?
    Yes. The Battery Management System (BMS) will control it.
17. Can we see the battery percentage in the display?
    In the Growatt inverter, the battery level can be seen from the inverter display. In the GoodWe inverter, you can view it from the PV master app (no LCD display on the GoodWe inverter).
18. Can we extend the battery capacity later?
    Yes, that is possible.

Installation

19. What is the installation process? How long does it take?
    We first visit your premises and evaluate the panel installation location, inverter location and other electrical installation locations. The gathered data is handed over to the operations team together with drawings for the installation. The installation can be completed within one day. We have our in-house, well-trained and experienced operations teams who will carry out the installation. An engineer will oversee the entire process.
20. Are there any approvals required from other parties?
    For the system with the offgrid inverter, no approvals are required. If you are planning to use the hybrid inverter and export to the grid as well, CEB/LECO approval is required.
21. What is the process to get approval from CEB/LECO to connect the hybrid inverter with the main grid? Usually, how long does it take? Do you charge additionally for that? If so, how much do you charge?
    The pre-approvals must be taken from the relevant CEB/LECO area office. Requests with application forms and other documents must be submitted from both the client and the solar PV installation company. After getting the relevant documents, we can submit them for pre-approval on behalf of the client. CEB/LECO and procurement charges will be charged from you (around 60,000 LKR). The process can take approximately 2-3 weeks.
22. Can we install the hybrid inverter without CEB/LECO approval and keep it as a full off-grid system?
    Yes, we can. As long as you are not exporting power to the grid, approval is not required. If and when you decide to export in the future, CEB/LECO approval will have to be taken.
23. When selecting battery backup or the grid, does the switch happen automatically?
    Yes, it happens with a 10ms delay.
24. I have a concrete rooftop. I guess, to mount solar panels on a concrete roof, we might need to build an extra structure. Would you be able to build that structure? If so, how much will it cost?
    Yes, we can build the steel structure. We have done such structures for many clients in the past. Extra time would be required for that. Cost (Material + labour + transport) depends on the site condition and layout. We can evaluate and give you a quotation.
25. Do you do a separate grounding for this off-grid system or is it using the same home ground wiring?
    Separate grounding will be done but will be connected to the house earth to make equipotential bonding.

Service/Maintenance

26. What about the service maintenance? How often will you do the service, and how many free-of-charge services are there?
    We do the service every 6 months and the first year (2 services) will be done free of charge.
27. Will the damages caused by lightning be covered by the warranty?
    The warranty will not cover lighting damages, but the risk is mitigated by installing surge protective devices and solar panel frame grounding.
28. Does the system come with online monitoring capabilities (either a mobile app or a web portal)?
    Yes, online monitoring is available.

Scalability

29. When going with the Growatt inverter system or the GoodWe, is it possible to add more solar panels to the system in the future? If so, does your company provide such services?
    Yes, it’s expandable and we can provide that service. The amount of solar panels that can be added depends on the inverter capacity. For example, with the 5kW inverter, solar panels can be added up to a capacity of 6kW. If you want to increase further, we will have to go for another inverter.
30. Can we extend the system by adding more batteries?
    Yes, that is possible.
31. Does this help to reduce or make zero electricity bills when things get back to normal?
    Yes. When you add solar panels, it will definitely reduce the bill. Power generation from solar will be approximately 300 kWh monthly on average with a 3 kW system. However, for offgrid systems, electricity bill reduction will depend on the usage pattern as well. If you don't use much energy during the daytime, you will need extra batteries to store the energy. For example, if you install 3kW solar capacity and 5kW inverter + 5kWh battery, only 5kWh can be stored even though the 3kW system generates 10-12 units per day.

We hope you got a better understanding of Alta Vision Solar Powerwall. If you would like to proceed further or got more questions, do not delay any more. Reach our solar PV experts at Alta Vision Solar via 0717 666 555 or [email protected]