Setting up a mini system

[Orkeven]

So, I am a newbie on this and have been gathering information to equip myself sufficiently in order to be able to set up a system that will be optimal for me. I am currently located in a rural area and want to provide electricity for myself, to be able to ensure my gadgets and some appliances can be run, and on a needs basis. An operator advised that I get two 180W panels to be connected in parallel, then a MPPT 30/40A, a 3000W inverter and four lead acid batteries (like a truck battery).
I have been thinking about how well such a system will work.
Using an app I have estimated my total wattage to be 1488W, which brings my desired backup to be 1240AH for a 12V battery setup.
I don't need to be using all my appliances 24/7, I can swap some for others according to a scale of preference.
Assuming that 1240AH is my current desired battery backup, what will be a good setup - solar panels, charge controller, inverter and batteries, please?

Thanks in advance.

 

[Mattb4]

A few things that might help in your planning.

Battery amp-hour is a capacity rating for the battery based on the number of amps it can deliver starting at full charge til voltage drops too low to sustain draw. This is over a rated period of hours. In typical lead acid the standard is often 20 hours. Thus a 100ah battery over 20 hours will give you 5 amps of continuous loading. 100ah/20h=5a

Watts= Volts X amps This becomes watt hours if your watt draw goes to an hour or more. Example: 120w=12vDC X 10a. If you run that 10 amps for 3 hours you have used 360wh Suppose this is from your 100ah battery. 10a for 3 hours means 30ah was drawn from the battery capacity.

If voltage changes such as using an inverter to go from 12vDC to 120vAC. Watts and watt-hours stays the same but current draw changes since 120w at 12vDC = 10a but at 120vAC it would = 1a.

So armed with this you need to work out your loading based on running watts and total watt-hours for the day. Once you know your loading you can than think about how you will supply it. Batteries are not a supply they are storage for the supply.

PV panel ratings in watts are based on STC (Standard Test conditions) of 1000w per square meter of area. This is rarely achieved and mostly you are lucky to get 80% of rating. So taking your 2-180w panels this would mean they will be 360w at 80% or 288w peak. Over the day as the sun rises and sets you will get an average amount of productive hours such as 5 hours. This means that you multiply 5 hours times the panels watt rating and you have the amount of harvested energy for the day. 5h X 360w = 1800wh This supplies to your batteries for recharge and any additional loading you might need. Suppose it is just a 12vDC battery needing charged. 1800wh/12vDC=150ah (note: this is likely less due to inefficiencies in the process).

 

[Orkeven]

Thank you fo

A few things that might help in your planning.

Battery amp-hour is a capacity rating for the battery based on the number of amps it can deliver starting at full charge til voltage drops too low to sustain draw. This is over a rated period of hours. In typical lead acid the standard is often 20 hours. Thus a 100ah battery over 20 hours will give you 5 amps of continuous loading. 100ah/20h=5a

Watts= Volts X amps This becomes watt hours if your watt draw goes to an hour or more. Example: 120w=12vDC X 10a. If you run that 10 amps for 3 hours you have used 360wh Suppose this is from your 100ah battery. 10a for 3 hours means 30ah was drawn from the battery capacity.

If voltage changes such as using an inverter to go from 12vDC to 120vAC. Watts and watt-hours stays the same but current draw changes since 120w at 12vDC = 10a but at 120vAC it would = 1a.

So armed with this you need to work out your loading based on running watts and total watt-hours for the day. Once you know your loading you can than think about how you will supply it. Batteries are not a supply they are storage for the supply.

PV panel ratings in watts are based on STC (Standard Test conditions) of 1000w per square meter of area. This is rarely achieved and mostly you are lucky to get 80% of rating. So taking your 2-180w panels this would mean they will be 360w at 80% or 288w peak. Over the day as the sun rises and sets you will get an average amount of productive hours such as 5 hours. This means that you multiply 5 hours times the panels watt rating and you have the amount of harvested energy for the day. 5h X 360w = 1800wh This supplies to your batteries for recharge and any additional loading you might need. Suppose it is just a 12vDC battery needing charged. 1800wh/12vDC=150ah (note: this is likely less due to inefficiencies in the process).

Thank you for the robust response. Your last paragraph seems to really shine light on what I was hoping to get.
I want to work with the panels that I have for now, referring to the two 180W panels. I would like to build my system around this, and adapt my utility accordingly for my current location.
Can I use lead acid batteries like those used in cars and trucks? These are the ones readily available. Is there a way to build a working system using this type of battery?
Going by your calculation, which I am willing to work with, because we do get really good sunshine over here, I could use two car batteries rated 12V/75A connected in parallel. Yes?
However, the downside will be the poor depth of discharge for the car batteries. Is there a workaround for this?

*I am in Nigeria and we use 220V AC here.

Thanks in advance.

 

[Mattb4]

Lead acid starting batteries such as you find in cars and trucks will work but they do not have a long life span. This type of battery is designed for heavy intermittent draws such as cranking a car over for a few minutes in order to start it. They suffer from more continuous draw use and failure to get fully recharged such as in a PV inverter setup. Typically you always want to limit your discharge to about 50% of the batteries rated capacity to gain as much life as possible.

So lets say you want to store that 150ah from a days solar production. You would want 300ah worth of lead acid battery. Thus if they are 75ah rated you would need 4 in parallel.

 

[scrubjaysnest]

And either deep cycle lead acid or lifepo4

 

[chrisski]

Recommend you look at Wills basic 400 volt system.

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

 

[Orkeven]

And either deep cycle lead acid or lifepo4

I was actually hoping to be able to cut the cost. It appears that isn't possible. I may have to wait and save some more in order to be able to set one up.
Thanks.

 

[Orkeven]

PV panel ratings in watts are based on STC (Standard Test conditions) of 1000w per square meter of area. This is rarely achieved and mostly you are lucky to get 80% of rating. So taking your 2-180w panels this would mean they will be 360w at 80% or 288w peak. Over the day as the sun rises and sets you will get an average amount of productive hours such as 5 hours. This means that you multiply 5 hours times the panels watt rating and you have the amount of harvested energy for the day. 5h X 360w = 1800wh This supplies to your batteries for recharge and any additional loading you might need. Suppose it is just a 12vDC battery needing charged. 1800wh/12vDC=150ah (note: this is likely less due to inefficiencies in the process).

So, I will like to build a system around the two 180W panels. By your calculations here, I could use a 12V/150ah battery. I have read that batteries can be discharged to zero and recharged to full from that zero. Can I use only one of such a battery for my setup? Will that be acceptably safe?
Will a PWM controller suffice, and at what rating? If not, what's the acceptable alternative?
What inverter rating will I need to use? I have read that a pure sine wave inverter is preferred.

Thank you.

 

[E. Cho]

You could use 1 x 150AH LiFePO4 battery. Going down to zero is possible but not recommended for long life. It also depends on what the BMS / Battery zero voltage actually is, 0 volts is really bad, in the 10.8 volt range is also zero battery capacity and not great, so you need to learn and figure out what the safest low voltage is. Lead Acid batteries have even worse zero capacity thresholds. PWM solar charge controllers can work but are less efficient in clouds and shade and mixed sunlight. MPPT solar charge controllers are preferred and require less babysitting to achieve best results. Inverter rating? Do you mean total and or surge Watts? That depends on your total load being drawn plus a cushion or more for high surge loads. Pure Sine Wave is desirable for many modern appliances and computer type electronics. But that doesn't always mean much if it is a low cost high frequency inverter and without a charger. Ideally, pure sine wave low frequency inverters work best, power more types of loads, have higher longer surge ratings and last the longest for durability.

LOTS of info to search and read the forums for. You need to get used to the terms and the math required.

Finally, you have not mentioned nor maybe considered weather, as solar requires direct strong sun for normal production. A passing cloud, tree shade or an overcast day can and will reduce solar production by 90-95%. So on an overcast day, even at noon, your 180W panel could only produce as little as 9 Watts! I am not kidding. My 2300 watt panels on many days in November through to now very often only produced 35-50 watts on dull overcast days. Solar means Sun, direct sun. Clouds and shade in most locations need to be considered and accounted for in sizing any system. So, if you get clouds or shade then your calculations and small system hopes are totally useless. Too few solar panels under clouds or shade won't be able to recharge your battery very quickly or at all, especially as you use more watts than the panels produce.

Read the many many other threads on small systems to get your head around this as all the questions you have, were asked and answered already. Don't buy anything until you get it, you know how to do the math, you have done the energy audit, then specced out the equipment you think you might want vs need, figured out a budget AND FIGURED IN how things will or will not work on CLOUDY DAYS.

 

[Orkeven]

You could use 1 x 150AH LiFePO4 battery. Going down to zero is possible but not recommended for long life. It also depends on what the BMS / Battery zero voltage actually is, 0 volts is really bad, in the 10.8 volt range is also zero battery capacity and not great, so you need to learn and figure out what the safest low voltage is. Lead Acid batteries have even worse zero capacity thresholds. PWM solar charge controllers can work but are less efficient in clouds and shade and mixed sunlight. MPPT solar charge controllers are preferred and require less babysitting to achieve best results. Inverter rating? Do you mean total and or surge Watts? That depends on your total load being drawn plus a cushion or more for high surge loads. Pure Sine Wave is desirable for many modern appliances and computer type electronics. But that doesn't always mean much if it is a low cost high frequency inverter and without a charger. Ideally, pure sine wave low frequency inverters work best, power more types of loads, have higher longer surge ratings and last the longest for durability.

LOTS of info to search and read the forums for. You need to get used to the terms and the math required.

Finally, you have not mentioned nor maybe considered weather, as solar requires direct strong sun for normal production. A passing cloud, tree shade or an overcast day can and will reduce solar production by 90-95%. So on an overcast day, even at noon, your 180W panel could only produce as little as 9 Watts! I am not kidding. My 2300 watt panels on many days in November through to now very often only produced 35-50 watts on dull overcast days. Solar means Sun, direct sun. Clouds and shade in most locations need to be considered and accounted for in sizing any system. So, if you get clouds or shade then your calculations and small system hopes are totally useless. Too few solar panels under clouds or shade won't be able to recharge your battery very quickly or at all, especially as you use more watts than the panels produce.

Read the many many other threads on small systems to get your head around this as all the questions you have, were asked and answered already. Don't buy anything until you get it, you know how to do the math, you have done the energy audit, then specced out the equipment you think you might want vs need, figured out a budget AND FIGURED IN how things will or will not work on CLOUDY DAYS.

Thank you. I have been doing a lot of reading around this subject matter, reading through as much as I can in the Beginners Corner, also reading from the owner's website because I would like to understand well enough. However, as far as I can tell, I can make do with the 1800Wh as calculated based on the two 180W panels above until I can afford to get something bigger with more panels and batteries, for example. Where I live, I have very good sunshine all year through. For example, last year we experienced a few days when sunshine was around two hours per day, this lasted a week. Otherwise, nature basically guarantees us a minimum of 4 hours of sunlight everyday. On some days, the sun is already bright enough by 0700 hours all the way to 1500 hours at my house.
It gets cold, so refrigeration is not a priority but, based on calculations from others, I can manage with the above. I don't use power tools. Plus, this is intended as a backup initially, but then eventually become a starting point towards going off-grid, as I can hopefully build up from there as funds permit.

Thank you.

 

[Orkeven]

By the way, I have a concern that regards usage of power while the setup is charging.
I may have to go for a LiFePO4 battery, maybe a 12V 100-150Ah, for now. With 5 hours of adequate sunlight, I can get it to fully charge per day (I wonder if that is safe, essential or necessary) using the two 180W panels mentioned. I'm assuming a 30A MPPT will suffice, although the one that comes recommended here is quite expensive for me and doesn't have a screen for monitoring its use. I noticed that most installers in my region of the country set them up using PWM as SCC which usually comes with a screen that shows what's happening on the panel side and the battery side. I brought up the PWM here to gain more understanding of its likely preference or otherwise.
My concern, however, is regarding how to use the system while it is charging. Is this something that is inbuilt or would I have to make it?

 

[E. Cho]

By the way, I have a concern that regards usage of power while the setup is charging.......
.
....... My concern, however, is regarding how to use the system while it is charging. Is this something that is inbuilt or would I have to make it?

Using power while solar charging or not charging is what the inverter does. It inverts / converts available solar and or stored DC power in the battery, into your AC power use. The solar charge controller takes high voltage DC current and inputs it into the lower voltage of your battery but at higher amps to try to keep the battery charged. ALL POWER to the inverter / your appliances / "your load" comes from / through the battery. Power always moves from the higher voltage (the source) to the lower voltage (your loads / appliances. If your appliances are off, then your battery becomes the lowest and only voltage point for your charging current to go to. If your appliances via your inverter, use more power than the Sun to the Charge Controller can supply, then you just draw more directly from the battery without excess from the solar panels to add to the battery. It works like flowing water.

Low cost, small wire and small systems often have more inefficiency or power losses than the opposite. Your panels will likely not put out 180 watts but more like 150+/- in optimal sun and angled positions, small and long wire runs have voltage drops, "inverters" especially low cost and high frequency have higher power uses even if in stand by / not inverting and may not handle surge loads well. All things to consider, as well as the efficiencies of your appliances and your brain's desire or ability to conserve or waste power.

Sounds like you need to keep learning before you buy anything. Lots of unethical or wasteful "installers" out there, so don't always go by the example of "installers", whatever you mean by that. Go slow, some brains, at least mine, takes quite a bit of time to learn and remember the process, the math and then doing the build with efficiency, conservation and safety.

 

[Orkeven]

Using power while solar charging or not charging is what the inverter does. It inverts / converts available solar and or stored DC power in the battery, into your AC power use. The solar charge controller takes high voltage DC current and inputs it into the lower voltage of your battery but at higher amps to try to keep the battery charged. ALL POWER to the inverter / your appliances / "your load" comes from / through the battery. Power always moves from the higher voltage (the source) to the lower voltage (your loads / appliances. If your appliances are off, then your battery becomes the lowest and only voltage point for your charging current to go to. If your appliances via your inverter, use more power than the Sun to the Charge Controller can supply, then you just draw more directly from the battery without excess from the solar panels to add to the battery. It works like flowing water.

Low cost, small wire and small systems often have more inefficiency or power losses than the opposite. Your panels will likely not put out 180 watts but more like 150+/- in optimal sun and angled positions, small and long wire runs have voltage drops, "inverters" especially low cost and high frequency have higher power uses even if in stand by / not inverting and may not handle surge loads well. All things to consider, as well as the efficiencies of your appliances and your brain's desire or ability to conserve or waste power.

Sounds like you need to keep learning before you buy anything. Lots of unethical or wasteful "installers" out there, so don't always go by the example of "installers", whatever you mean by that. Go slow, some brains, at least mine, takes quite a bit of time to learn and remember the process, the math and then doing the build with efficiency, conservation and safety.

By installers, I meant technicians who sell and install solar energy systems in our parts. They are just referred to as "solar installers" here for simplicity. I hope this clarifies that.

 

[Easyyokefilms]

By installers, I meant technicians who sell and install solar energy systems in our parts. They are just referred to as "solar installers" here for simplicity. I hope this clarifies that.

Thank you fo

Thank you for the robust response. Your last paragraph seems to really shine light on what I was hoping to get.
I want to work with the panels that I have for now, referring to the two 180W panels. I would like to build my system around this, and adapt my utility accordingly for my current location.
Can I use lead acid batteries like those used in cars and trucks? These are the ones readily available. Is there a way to build a working system using this type of battery?
Going by your calculation, which I am willing to work with, because we do get really good sunshine over here, I could use two car batteries rated 12V/75A connected in parallel. Yes?
However, the downside will be the poor depth of discharge for the car batteries. Is there a workaround for this?

*I am in Nigeria and we use 220V AC here.

Thanks in advance.

Bro, first, ditch the idea of Car batteries. For solar storage, you need deep cycle discharge batteries. Car batteries are not made for that. It wont last you more than 6months that is if you even get 6months.
Second, most of the solar panels sold in Nigeria are junks imported from China. Their true rating is sometimes half of the advertised rating. Infact sometimes 1/3 of it. I have two 300W panels bought in Lagos, and the best I have got from them combined is 250W for panels that are advertised as 600W. And my charge controller is a Renogy MPPT charge controller so it is definitely not my charge controller that is not effecient. So that 180W you are planning may not give you more than 80W sadly. So you need to overpanel your setup(Buy many panels than the initial amount you planned)
Third, you end up saving more money in the long run if you end up buying LIFEPO4 battery than any other type of battery. Get a Redodo or Litime battery on amazon and use a drop shipping company to help you ship it to Lagos. Dont use a lead acid battery as they dont have a long life span like LIFEPO4 batteries

 

[KITROBASKIN]

Welcome and congratulations for choosing to get some of your power from the sun!

Do you have a cold time of year where the batteries you propose to get might be subjected to freezing? Lead acid batteries designed for home power could be best, otherwise LFP batteries offer so much more in longevity and use.

Are you able to confidently order from Amazon or some other avenue than solar installers?

PWM Solar charge controllers of decent quality should be fine for your use.

Respect your electronic items by getting a decent quality true sine wave inverter. I am guessing that the 3000W inverter suggested to you is not. Find out what the standby consumption (idle draw) of the inverter and consider that in your calculations. Remember that one can turn off their inverter if no loads need to be energized (though some people do not like doing that).

Like you, I started out with a very modest system that enhanced my quality of life. Because I purchased quality components, the panels (2X75W nominal), charge controller (PWM) and inverter (pure sine wave) are still going just fine after more than 20 years. Still on third set of lead acid (quality manufacturer, respectfully treated) batteries. LFP batteries are the way to go as long as you can avoid trying to charge them when they are freezing. Low temperature disconnect or heated batteries are an option.

Hopefully you have fun; making good choices as your money allows!

 

[Orkeven]

Bro, first, ditch the idea of Car batteries. For solar storage, you need deep cycle discharge batteries. Car batteries are not made for that. It wont last you more than 6months that is if you even get 6months.
Second, most of the solar panels sold in Nigeria are junks imported from China. Their true rating is sometimes half of the advertised rating. Infact sometimes 1/3 of it. I have two 300W panels bought in Lagos, and the best I have got from them combined is 250W for panels that are advertised as 600W. And my charge controller is a Renogy MPPT charge controller so it is definitely not my charge controller that is not effecient. So that 180W you are planning may not give you more than 80W sadly. So you need to overpanel your setup(Buy many panels than the initial amount you planned)
Third, you end up saving more money in the long run if you end up buying LIFEPO4 battery than any other type of battery. Get a Redodo or Litime battery on amazon and use a drop shipping company to help you ship it to Lagos. Dont use a lead acid battery as they dont have a long life span like LIFEPO4 batteries

For the panels, I intend to have them tested at the shops before purchase, as someone I know was able to do that.
Those lifepo4 batteries seem really expensive for me right now. However, I should be able to upgrade to them down the line.
Thank you.

 

[Orkeven]

Welcome and congratulations for choosing to get some of your power from the sun!

Do you have a cold time of year where the batteries you propose to get might be subjected to freezing? Lead acid batteries designed for home power could be best, otherwise LFP batteries offer so much more in longevity and use.

Are you able to confidently order from Amazon or some other avenue than solar installers?

PWM Solar charge controllers of decent quality should be fine for your use.

Respect your electronic items by getting a decent quality true sine wave inverter. I am guessing that the 3000W inverter suggested to you is not. Find out what the standby consumption (idle draw) of the inverter and consider that in your calculations. Remember that one can turn off their inverter if no loads need to be energized (though some people do not like doing that).

Like you, I started out with a very modest system that enhanced my quality of life. Because I purchased quality components, the panels (2X75W nominal), charge controller (PWM) and inverter (pure sine wave) are still going just fine after more than 20 years. Still on third set of lead acid (quality manufacturer, respectfully treated) batteries. LFP batteries are the way to go as long as you can avoid trying to charge them when they are freezing. Low temperature disconnect or heated batteries are an option.

Hopefully you have fun; making good choices as your money allows!

Thank you.
I have come to learn that lead acid means different things to different people because there are different types of lead acid batteries, even for the ones compatible with solar energy systems. So, what exactly do you mean by lead acid batteries? Over here, I only just recently found out that tubular batteries are lead acid deep cycle batteries, although I don't know if they can be discharged to zero and then back to full like the LiFePO4.

 

[E. Cho]

Thank you.
I have come to learn that lead acid means different things to different people because there are different types of lead acid batteries, even for the ones compatible with solar energy systems. So, what exactly do you mean by lead acid batteries? Over here, I only just recently found out that tubular batteries are lead acid deep cycle batteries, although I don't know if they can be discharged to zero and then back to full like the LiFePO4.

No, not even deep cycle lead acid batteries made for off grid use should be discharged more than 50%. I had some specialized lead acids for 15 years.

Also, STOP thinking that LiFePO4 batteries can be cycled to Zero!!!! Doing so more than a few times will at least start damage to 1 or more cells, if not all cells. 10-20% is more reasonable but they should have a very good BMS that can have customized discharge settings to STOP Over Discharging at a safe voltage. THAT is what is meant by ZERO!, where your comment could mean 0-2 volts per cell which would be REALLY BAD. LiFePO4 cell voltage drops off EXTREMELY quickly when approaching 10+% SOC and if a large load is being applied, if not under supervision, then it could fall to low and damage causing SOC / state of charge voltage FAST!!!! So STOP saying you can discharge to zero without knowing what zero means and the consequences of zero!!!!!! Zero WHAT???? Define Zero!!!!!

Battery University Read here for info on lead acid and other batteries.

 

[MrNatural22]

So, I am a newbie on this and have been gathering information to equip myself sufficiently in order to be able to set up a system that will be optimal for me. I am currently located in a rural area and want to provide electricity for myself, to be able to ensure my gadgets and some appliances can be run, and on a needs basis. An operator advised that I get two 180W panels to be connected in parallel, then a MPPT 30/40A, a 3000W inverter and four lead acid batteries (like a truck battery).
I have been thinking about how well such a system will work.
Using an app I have estimated my total wattage to be 1488W, which brings my desired backup to be 1240AH for a 12V battery setup.
I don't need to be using all my appliances 24/7, I can swap some for others according to a scale of preference.
Assuming that 1240AH is my current desired battery backup, what will be a good setup - solar panels, charge controller, inverter and batteries, please?

Thanks in advance.

The simplest and Best bet for your specs would be an Ecoflow Delta 2 or better a Delta 2 Max all one plus a couple 200 watt panels. All easily portable and quality product.
Search Wills utube videos for a honest review on the Delta2.

 

[KITROBASKIN]

Types of Lead Acid Batteries & How to Charge Them

Our controllers are designed for Lead Acid batteries which were the first rechargeable battery ever built & the most common rechargeable battery.

www.morningstarcorp.com

Save up money, buy LFP battery. It will cost you less if you hold your end of the arrangement.