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Cheap Solar System for Power Outages in Yemen

Solar_Ali

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Joined
Aug 23, 2020
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6
Hi everyone

First I would like to thank Will for his free educational videos on YouTube. They got me even more enthusiastic about solar than I already was!

I am actually planning to start designing and selling solar systems for homes in Yemen. Power outages are very common there and can last up to 3 hours daily in the area where I'm selling. People there use diesel generators to deal with the power outages but the diesel price is high. I thought it might be a good investment to install solar power and help them with the power outages at least to power their necessary home appliances.

I have calculated the average load to be around 650W (powering only necessary appliances) that will rely on batteries for 5 hours daily (just in case power outage time extends in the future). The upfront cost has to be the cheapest because of the financial status of the average family there so I'm looking for the cheapest possible options that are safe and somewhat reliable. It seems that the batteries have to be sealed lead acid because of the upfront cost issue even though I love LiFePO4. Since I will rely on both grid and battery power I will probably use an all-in-one system (MPP seems cheap & reliable) and set it to grid priority to make things simple. I found some panels that are $0.2/W which is great. My biggest concern is shipping cost since all of these components are heavy.

Is it possible to design such a system that would cost anything below $1000 including shipping cost?
Anybody has experience with Alibaba solar panels, AGM/GEL batteries, or all-in-one systems?
Any general suggestions or recommendations?

Thanks in advance
 
Hi everyone

First I would like to thank Will for his free educational videos on YouTube. They got me even more enthusiastic about solar than I already was!

I am actually planning to start designing and selling solar systems for homes in Yemen. Power outages are very common there and can last up to 3 hours daily in the area where I'm selling. People there use diesel generators to deal with the power outages but the diesel price is high. I thought it might be a good investment to install solar power and help them with the power outages at least to power their necessary home appliances.

I have calculated the average load to be around 650W (powering only necessary appliances) that will rely on batteries for 5 hours daily (just in case power outage time extends in the future). The upfront cost has to be the cheapest because of the financial status of the average family there so I'm looking for the cheapest possible options that are safe and somewhat reliable. It seems that the batteries have to be sealed lead acid because of the upfront cost issue even though I love LiFePO4. Since I will rely on both grid and battery power I will probably use an all-in-one system (MPP seems cheap & reliable) and set it to grid priority to make things simple. I found some panels that are $0.2/W which is great. My biggest concern is shipping cost since all of these components are heavy.

Is it possible to design such a system that would cost anything below $1000 including shipping cost?
Anybody has experience with Alibaba solar panels, AGM/GEL batteries, or all-in-one systems?
Any general suggestions or recommendations?

Thanks in advance
One point I would like to ask is... 650W

is that the demand or the total?

In other words, are you powering this all day, or only a few minutes every so on?
It is important to know how much solar you need, and to know how much battery to buy.
Don’t just find the watts your combined loads will draw... calculate the runtimes per day ALL the loads actually consume.

A 100W lightbulb only pulls 100W, but if left on 24 hours, it consumes 2400Wh of battery... so you need to discover the Wh of your loads to properly size the system.
 
One point I would like to ask is... 650W

is that the demand or the total?

In other words, are you powering this all day, or only a few minutes every so on?
It is important to know how much solar you need, and to know how much battery to buy.
Don’t just find the watts your combined loads will draw... calculate the runtimes per day ALL the loads actually consume.

A 100W lightbulb only pulls 100W, but if left on 24 hours, it consumes 2400Wh of battery... so you need to discover the Wh of your loads to properly size the system.
Yes of course I did that. I am calculating the outage time +2 hours which is 5 hours. So I need a battery bank that can handle 650W x 5 = 3,250Wh
 
Yes of course I did that. I am calculating the outage time +2 hours which is 5 hours. So I need a battery bank that can handle 650W x 5 = 3,250Wh
Ok, good information.

What kind of loads are the 650W? Any inductive loads needing startup current?
 
Ok, good information.

What kind of loads are the 650W? Any inductive loads needing startup current?
A fridge and a small evaporative cooler. I'm guessing the fridge will be on 24/7 and does not need a startup current if the switch between grid and battery is smooth. But the evaporative cooler will need a startup current for its motor.
 
you will need to size a significantly larger battery bank if you want any longevity to the lead acid batteries. I believe its no more than 25 percent discharge per hour, with a recommended dod of no more than. 50% for longevity. you would need to build a 6kw, or roughly 500ah of 12v batteries.
I dont know what diesel costs there, but the payback on a solar system isn't measured in days, its measures in years. If you say money is tight, capital improvements probably isnt ideal.

However if its only a matter of unstable grid power, you could just do a UPS system, without the solar. The grid charges the battery when avaliable, and the battery takes over when the grid isn't. You also don't have to deal with the massive shipping expenditure of solar panels.
Maybe you can get the smallest all in 1 units, it can work the same way. They can always add solar panels later if the desire.
 
you will need to size a significantly larger battery bank if you want any longevity to the lead acid batteries. I believe its no more than 25 percent discharge per hour, with a recommended dod of no more than. 50% for longevity. you would need to build a 6kw, or roughly 500ah of 12v batteries.
I dont know what diesel costs there, but the payback on a solar system isn't measured in days, its measures in years. If you say money is tight, capital improvements probably isnt ideal.

However if its only a matter of unstable grid power, you could just do a UPS system, without the solar. The grid charges the battery when avaliable, and the battery takes over when the grid isn't. You also don't have to deal with the massive shipping expenditure of solar panels.
Maybe you can get the smallest all in 1 units, it can work the same way. They can always add solar panels later if the desire.

Good thoughts. I actually reached the same values in my calculations. Two 12V 250AH batteries in parallel should be good.

I'm starting to consider the idea of having a UPS system. And as you said they can add solar panels later if they want.

One thing I'm worried about is the startup current of inductive loads like fridges and evaporative coolers. Any idea how to consider that in sizing the battery? Will it affect the discharge rate and hence shorten the life of the battery or even damage it?
 
The evap cooler probably is a straight AC motor but the fridge might be an inverter type. If so, you can ignore it for that purpose as it will soft start and have a good power factor too.

If the fridge is a standard type, not inverter, the few seconds startup draw will be handled by 500AH of battery without even blinking. It won't degrade your battery. What you should do though is use heavy gauge wire from the battery to the inverter to avoid voltage drop during that time as that may be enough to trip your inverter off.
If you know the run amp rating of the evap cooler multiply it by 3 and that will do, or if you can check the label on the motor or cooler chassis, if you are lucky it will mention LRA (locked rotor) current.
 
3 hour power outage seems like heavens at times. We are slowly creeping back to 5, let's hope the monsoons helped out this year, used to have a national average of 12 hours :censored:. Just remember with solar, if the power goes out at night, things will run on the battery. If your batteries die, it is still night, well....you know the drill. Same thing with the UPS.

Another thing to keep in mind with lead acid, a failure in one cell causes the whole bank to weaken immediately. People will not keep the right charging voltages, water level, store/running temperatures. All leading to shorter battery life of 6months to 2 years. I am assuming the average person does not know these details in Yemen like in Pakistan. They just want plug and play solutions. So be mindful of that.
 
depends on the fridge. Evap coolers usually aren't huge draws of power, but they are continuous draws. fridges cycle on and off.

on the lead acid battery issue... i just had yet another one die in my solar setup. battery was less than 6 months old. in series 24v setup, 23.5v cut off. 28.2v cut at the top.
1200w of solar. I think i left the charge rate too high (60a) and the full solar power dumping into the battery... i don't think it liked it much.
 
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