Here are 8 top mistakes people make going solar
#1 Myth: My solar system size is based on how many outlets are being used
All outlets are made the same, but the appliances that are plugged in are not. An outlet can power an appliance that requires just 5 watts per hour, or 2000 watts per hour. The power consumption is determined by what each appliance needs to run. For example, a phone generally needs only 5 watts per hour, which by itself would need very little amounts of solar panels and equipment. Compare this to a stove top that can consume 2,000 watts in the same hour. If you were running a kitchen, you would need a lot of solar panels and equipment. Appliances that generate heat like an iron, kettle, hair dryer, oven, or hot plate require the most energy for households. Commercial equipment and machinery are in a whole other category, and not covered in this article.
Appliances with a motor, like a desktop computer, fan, or refrigerator can also big consumers. To power a desktop for 24 hours, depending on how old the desktop computer is, can require 100-200 watts per hour. This can be 2.4 - 4.8 kilowatt hours (kWh). By comparison, a laptop may consume 50-75 watts per hour, or only 1.2 - 1.8 kilowatt hours (kWh). In the case of computers, the cost of solar equipment to power just one desktop computer could buy you 5 entry level laptops and the cost of solar equipment to power them.
Appliances that have a motor, when first plugged in, require a "surge," or a high amount of power in one short blast, to get the appliance running. A good rule of thumb is to take the running wattage of an appliance and multiply it times three when you plug it in. So a refrigerator that may only use 100 watts per hour, when first plugged in will require 300 watts. This means that your inverter needs to be able to deliver this amount of power, that you have that power available either stored in batteries, from direct solar power, or from the grid. This also means that your circuit breaker needs to be able to handle this surge.
It also depends on how many appliances are plugged in and actively used. Ten outlets with desktop computers being plugged in and running continuously will require exponential power than laptops that are plugged in and already fully charged.
The best battery brands on the market
#2 Myth: I can use existing bulbs & appliances
Choosing the right brand and capability can be quite confusing. One thing is for sure, if your installer hands you a quote with the brand "solar inverter" without a brand name, you will probably be getting low quality gear that will last only a short time - then you have to buy it again.
Inverters: Brands are made for specific functions. Inverters are the "brains" of the operation. Does the system need to be extended and grown in the future to larger size solar and battery arrays? Will the system eventually be grid tied? Does the system need a blend of prioritized power, for example first solar, then grid, then battery, then diesel generator? Inverter brands specialize in various functions, and what you decide to use will reflect both current and future expansion needs.
Solar panels: The best brands are REC, NEMO (Germany), LG (Korea), and Sharp (Japan). If you buy a Chinese made solar panel, it is important to note where the panel was made to be installed. The panels made for the developed world like USA or Europe will be a Tier-1 panel, versus panels made in China for the developing world are notorious for being Tier-5 quality, and have a lot of performance issues. We recommend staying away from these panels.
Batteries: The best battery brands on the market are Tesla Powerwall, Tesvolt, BYD, and LG Chem.
#3 Myth: I don't need an energy audit
This mistake may be the most costly. Just because your utility bill says you use 35kWh per day, doesn't necessarily mean that you should buy a system large enough to accommodate that load. Instead, first go through everything you are plugging in. Let's say you have 20 traditional incandescent lights in your house, at 60 watts per hour each, turned on for 7 hours each day. If you replaced them with 15 watt LED lights, you would save 6.3kWh in 24 hours, which can save thousands of dollars.
Energy Saving refrigerators use half and sometimes a third of energy that older refrigerators use. Old Tube TVS or plasma tvs use exponentially higher amounts than LED tvs (if your tv was purchased within the last 10 years, it is likely an LED). Desktop computers can be swapped out for laptops and electric convection stoves/ ovens can be changed for induction. Click here to see a comprehensive list of appliances and their average wattage consumption. Of course, different brands of the same product will have different consumption levels.
#4 Myth: Any installer can put in my system
Having a "solar installation" certificate is the very first eschelon in installation. In the United States, this is equivalent to a NABCEP qualification, MCS in England, and TEVET for many places in Africa. This certifies the installer to get up on a roof, install the steal and aluminum mounts, solar panels, small inverters and charge controllers, and an array of lead acid batteries. The second element of an installation requires the electrical installation of hard wiring everything together. This requires electrical certificates and more training. The third and most elite eschelon are the skilled installers who have had years of training both by the leading brands and also with design tools. Most of the time of this third level of engineer is spent on the computer, programming the inverters to interact with the rest of the equipment.
All three levels of training are required to install a larger mini grid so that it integrates seamlessly with the power distribution and internal wires of the buildings on campus.
#5 Myth: Cheap Lead acid batteries will work in any installation
Lead Acid batteries can be a fine option for your system, but only if the ambient temperature is always below 25C/ 72F and iff there is good air flow. Just like a lead acid battery can be killed if completely drained, so to can it be permanently damaged every time the ambient temperature becomes too hot. The battery has produced degrees of permanent damage for every 1 degree C that the temperature goes beyond the threshold. These numbers vary, depending on the brand and the internal chemistry. There are a whole host of batteries within this class, including deep cycle, Gel, AGM, and others.
Remember that batteries are active chemicals inside a container, and when they get too hot placed they will react, sometimes creating some incredibly unsafe situations for anyone in the room.
Note from the photo, that wiring these batteries one-by-one can create some safety hazards such as wires connected improperly, if metal touches both posts at the same time (kaboom!), if a mouse nibbles on a wire, or if the wires are too small, all create safety concerns. For large installations that have 100+ batteries, keeping track of their wiring schedules can be tricky. We don't advise using lead acid batteries in most cases, unless the budget really can't afford anything else. They are old technology and a temporary solution. African MiniGrids will help you select the safest, most productive battery for your system.
#6 Myth: All batteries will last for many years
Many batteries sold in Africa, have around 350 cycles. This means if the battery is discharged down to 50% every single day, and fully recharged the next day, then the battery will last just under a year. Batteries that are discharged just 20% before being fully recharged will have much higher cycle life which can add years of life to the battery. As per the example to the right, this battery will have 8,500 cycles if discharged just 20% every single time of its life or over 20 years, but drops down to only 3,00 cycles if discharged 50% every single time, or over 8 years. But who wants to only use 20% of a battery? There are some efficiency costs associated. Remember that no lead acid battery can be fully discharged, and it is recommended not to discharge any lead acid battery more than 50%. This is called Depth of Discharge, or DoD. This means that you need to buy
double the amount of battery storage space as what you will actually use. Some battery makers will be a little clever and claim a high number of cycles at DoD 20%, meaning, you don't really have much battery to use for many cycles, so the high cycle life in this case is really misleading.
It's really important to line up all the cycles, next to how much USABLE battery space there is in terms of depth of discharge, and then compare their respect price per usable watt.
An NMC battery will allow 100% discharge, every single day. Most LiFePO batteries allow 80% -90% discharge, and only one brand, BYD, claims to allow 100% discharge.
#7 Myth: Lead Acid Batteries are the least costly choice for my solar system
Lead Acid batteries are by far the cheapest entry point cost, but if you look at them over a 20 year period, they end up being the most expensive. This is because Lead Acid batteries would need to be replaced at least twice for 7-batteries, and more times if the battery is lower quality.
Conversely, buying the best technology battery that will last 30-years at the highest price is also not recommended, as we believe that the technology within the next 10 years will change dramatically, and the price point will come down. Why buy a state of the art, $5,000 microwave in the 1980s right when it comes out, only to find that they can be bought for as low as $100 twenty years later? For this, we recommend value products, buying a LiFePO battery by BYD, LG Chem, or Simpliphi, in that order.
African Mini Grids will help you think through what is the best value for money battery solution.
#8 Myth: I can get by without batteries
After all of the fires and blackouts in California due to the fires, many homes started installing solar power on top of their roof tops. But when the blackouts hit, they also were coming home to dark homes. This is because they forgot to buy batteries. It's important to understand how much electricity you need at night, when most of us start turning on lights, doing household chores like laundry, cooking our dinner (one of the highest power consumption activities), and watching tv. To do these things at night, after the sun goes down, requires the energy you created during the daytime with solar panels, to be stored in your batteries.
If your system is completely off-grid, as a rule of thumb, we suggest 60-70% of your daily load consumption to be stored in batteries. This means if you use 36kWh per day, then you should have about 21-25kWh. If you aren't completely off-grid, and blackouts are quite unusual, you may want to just run limited amounts of appliances at night, like your lights and tv at night. This would require a lot less power, and a lot less money. Assuming you would turn on only 4 LED lights at the same time for a few hours, and a tv that would run for four hours, you would get the job done with a 1kWp solar array and a small 2.5kWh LiFePO battery.
Where we work: Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, The Central African Republic, Chad, Comoros, The Democratic Republic of the Congo, Republic of the Congo, Cote d’Ivoire (Ivory Coast), Djibouti, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Gabon, The Gambia, Ghana, Guinea, Guinea, Bissau, Kenya, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Rwanda, São Tomé and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, Sudan (North), South Sudan (Rep.), Swaziland, Tanzania, Togo, Tunisia, Uganda, Zambia, Zimbabwe, Sub Saharan Africa, South Africa, Johannesburg, Cape Town, Pretoria, Papua New Guinea, India, Guatemala