If you have a good Charge Controller {CC} with Battery Technology Source {BTS}, you don't have to worry about overheating or swelling of Batteries.
My name is Rasaq Adeleye I started my career in Electrical trade at Government Technical College Idi Aba, Abeokuta early 90s. Worked in two major multinational companies in Nigeria for years, have been working in the diesel generator company since 2007 and later diversified into the renewable energy sector in 2016. Presently, I manage one of the foremost renewable energy companies in Nigeria_ my own as the Technical Director.
What I will be sharing in this context is the span of my experience in the renewable energy fieldwork. I relate with clients on a day to day basis via telephone, emails and site visits and I must tell you I have seen a lot of poorly done jobs in places.
Among them are listed as follow :
1️⃣ Mixing up solar panels or what we call mismatching.
Customer A has an existing installation using 6pcs of 200W and wants to upgrade. Some installers if they cannot get 200W in the market will just get another capacity say 250W and add to the system. This is very wrong and the customer will not get value for his money because there will be a high loss of power in the system and he will complain.
2️⃣ Buying Inferior products.
This is very common these days. I got a call the other day for a site visit on a solar system. The customer complained he is not enjoying it and that he didn't trust what has been done. It was an array of 15pcs of 250W installed about a year or so. After checking the whole setup, I discovered all the panels have gone bad. The cables have turned to powder. What a waste of money and time. I am sure that the installer will sleep in the police station that day.
3️⃣ Mixing up batteries.
You get to a site and you will see a 48v system with three different battery makes. Two quanta mix up with luminous and Prag battery just like a makeup gone bad. The battery makes differs so are their charging parameters. The bulk voltage for quanta batteries is different from Prag batteries same applies to Deka batteries. When you join them together, the inverter will struggle to charge them and the batteries will go bad sooner or later.
4️⃣ Using PWM instead of MPPT.
Using an MPPT SCC helps you to harvest close to 90% of the energy yield of your array while PWM will only harvest about 55 to 60%. For a professional, losing energy is money lost. While harvesting 60%, when I can get 90%.
5️⃣ Basing your design on 100% panel output.
This is a bit techy now. You can not get 250W power out of a 250W panel consistently. Many factors can create a solar panel like dirt, quality of the solar cell, solar irradiation, weather conditions etc. Designers will always do 80% per panel so you won't have issues with your customer.
6️⃣ Installing under shade.
This is very wrong and unprofessional. 10% of shading can result in an almost 50% loss in the energy yield of your array. The client will just keep calling that he/she is not enjoying the system and can take it up with you. Though prices of solar panels and their accessories are coming down unlike what we have earlier when I started, it is still very expensive for an average Nigerian. So anyone who has decided to invest in Renewable Energy will want value for money and not less. A complete 2kw hybrid solar system will cost about #1.2m to #1.5m. That is enough to buy a Nigerian used car.
7️⃣ Under-sizing cables.
There are so many electricians now that have added Renewable Energy to their portfolio. Because they can use 4mm² cables to power a 1.5hp AC, they believe that works for DC systems too_ No way. I have seen where they use 2.5mm² or so to wire a 5kw solar system over a long distance. This is very wrong. The losses will be huge. For ease of wiring, there is a cable chart for the DC system online_Get one here.
8️⃣ Using Vmp for your design instead of Voc.
Another techy part. Always use open-circuit voltage because that is what your panel gives when no load is on it. Many charge controllers have been damaged because of this.
9️⃣ Using Imp instead of Inc.
I always use the short circuit current of the panel when designing my systems. It is the maximum current your panel can give and it is better if you use it.
🔟 Improper orientation of solar panels.
Nigeria is in the Northern hemisphere hence your panels must face south for a better harvest of solar irradiation. I have many panels facing East, North etc. Yes, it will work but not a full capacity and the customer will complain.
1️⃣1️⃣ No proper protection mechanism for the solar system.
Someone has invested #2million and within 3 months, the inverter has gone bad due to a surge arising from lightning and you think the client will smile with you. No way! Proper Earthing should be done and Surge protection devices (SPDs) that protect sensitive electrical equipment within the PV system from over-voltage which can lead to reduced life expectancy and sometimes failure should be used to protect the gadgets from damage.
1️⃣2️⃣ Not educating the client on how solar panels work.
Some installers because of the money they will make will promise the client heaven and earth. Weather affects solar panels' performance and particularly during the rainy season. To protect your batteries, the client should be ready to use the generator to compensate for the charging.
1️⃣3️⃣ Under-sizing battery capacity.
Your batteries are the reservoir for your energy after sunset. The more the load, the lesser the runtime.
If you under-size your batteries, your client will not allow you to sleep at night.
1️⃣4️⃣ Poorly terminated cables.
Like I said earlier, DC cable runs and termination is different from AC. Always use a cable lug when terminating to prevent arcing and losses at the terminal. This can cause fire outbreaks and terminal corrosion.
1️⃣5️⃣ Not using DC breakers between Array, battery bank and SCC
In SCC installation, the first step is to connect your batteries then the array. Using the breaker and putting it off will help you prevent damage to the SCC when working on the batteries.
1️⃣6️⃣ Using AC breakers in place of DC breakers.
Saying all are breakers_ Not true. DC breakers are quite different in functionality from AC. Don't put round pegs in square holes.
1️⃣7️⃣ Confusing daylight hours with peak sun hours.
In designing solar systems, we use PSH. The PSH is when the sun is at its peak and should not be confused with the daily sunlight. The value depends on your location. In Nigeria, the value ranges from 4.5 to 7hrs.
1️⃣8️⃣ Exposing your cables to rain and heat on the roof.
Sometimes I see some cables flying on the roof without any protection whatsoever and I shake my head. The temperature on the roof is high and will damage the cables. Your cables should be in PVC and flexible pipes.
1️⃣9️⃣ Improper arrangement of cables.
The other day I saw a solar installation with cables flying all over. It was really irritating and very unprofessional. It can lead to fire outbreaks. Part of our job is to add beauty to the client site and not just fly cables here and there.
2️⃣0️⃣ Not visiting the site for proper assessment before sending a quote.
Nothing can be compared to a proper site visit. Many installers have run into debts and probably lose some credibility because they have quoted and paid only to discover that they will need like 100m cable in place of the 40m quoted.
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