Hello DIYers! In setting up our DIY off grid solar power, We will be needing five components. First, is the solar panel to generate the power. Second, is the charge controller to charge our battery. Battery to store the energy.
Inverter to convert the DC to AC power. And a lot of questions after questions after questions. To start our off grid setup, let us first go to the part one: ASSESS YOUR SITUATION In assessing your situation, we need to know first our power consumption. Thus, will base the size of our solar setup. To measure our power consumption, we will be needing a wattmeter.
A wattmeter has two functions. First, power consumption at a given moment. Take this as an example. an electric fan and a television We can measure their power consumption the moment we plug them because they have continuous power consumption while turned on. Second function of the wattmeter is power consumption overtime.
There are some devices that are sometimes turned on and then off and not working all the time eg. is a refrigerator. Once it is turned on, it is not really turned on all the time. When it is cold, it will automatically turns off. We need to measure its consumption overtime for one day or for 24 hours.
That is for the part one: to ASSESS YOUR SITUATION. I will show you a video sample in my household.
Let us start with the laptop. Guys, this is a typical consumption of our laptop. When it is on its full load, it ranges from 40 to 54 watts.
That’s the typical consumption of our laptop. Why do we use laptop at home? Because my wife is an online teacher and if you want to know how to be an online teacher, comment down below. And for our DC fan, as you can see it ranges from 17 to 18 watts. Look at our DC fan.
This is my DC fan as you can see, I am using an adaptor. I will also made a video on how to make a DC fan. This is the consumption of our DC fan. 17.5 watts We always use this fan all throughout the day.
And for our router, it ranges from 6.5 to 6.6 watts. Our router has low power consumption. Can you see that?
click the i button for your to know this one this is a DIY UPS made by DIY PINOY We still have one more load to include in our computation for our power consumption but we will not be using the wattmeter to measure it because I know that it is 9W.
You already saw our appliances that is running at home that will consume the power from the sun. Laptop = 52 W times 8 hours because we are using it for 8 hours for a total of *416WH DC fan = 17.5 W time 24 hours because we use it for 24 hours router = 6.6 W and we use it for 24 hours and the LED light = 9W time 16 hours and when we add them all that will be our the daily power consumption which is 1138.
4 WH so this this is what we needed to know first our daily power consumption Let us go to our PART 2: SIZING YOUR INVERTER We use inverter to convert DC to AC power. the power that we use at home is AC the 220 V the output in our solar is either 12V or 24V (DC) system and we will convert it and we will convert it to 220V AC using an inverter There are two types of inverter: Toroidal Inverter and this is is the normal inverter that is used in electronic devices like TV, charger 1000W there How to know the size of the inverter that we will use? for example we have an electric fan, laptop and TV let us compute their power consumption at the same time our AC electric fan is 60W and the laptop is 50W and 55W television so if we add them all, it’s 165W so that is the simultaneous power that we use so if we have this 1000W inverter, it can support our setup we only consume 165W compared to our 1000W inverter even if we consume 500W, it will still work it can support our setup let us now compare with a high power consuming appliances like rice cooker and washing machine rice cooker consumes about 500W once you plug it, it consumes 500 W if you’re using a washing machine, it consumes 550W If we add them, the total power is 1050W so our inverter will not work the best inverter to use is this 2000W inverter because it is better to use a toroidal inverter in motorized devices like washing machine Let us now move on to the PART 3 SIZING YOUR SOLAR PANEL To recap, we already know our daily power consumption and we already know the size of inverter to use.
For our part three, we will size our solar panel. In sizing our solar panel, we will be introduced with the term “SUN HOURS”.
Sun hours is the effective number of hours that we can maximize the power from the sun. In the Philippines, we have a range of 4.5 to 5.5 sun hours. If you are in Metro Manila you get 5 sun hours.
It’s a good thing that we know sun hours so that we have a basis for the output of our solar panel. Let us say that we have 100W solar panel. In Metro Manila we have 5 hours or 5 sun hours, if we will compute, the possible output of 100W solar panel is 500WH because we will multiply it by 5 that is the effective output of the solar panel the whole day 5 sun hours so 500WH is the output the is the ideal output of the 100W solar panel If you remember our daily need is 1138.4WH one 100W solar panel is not enough let us use three solar panel = 300W times five is 1500WH now our solar panel can supply the 1138.4WH that we need So, in sizing your solar panel, we always base in our load or to our daily power need.
Solar output should be more than what we need okay? In solar panel sizing, we are introduced with the rule number one. “You can only spend what you make.” So whatever power your solar panel produced that is the only power you can consume. No more extra power.
Unlike when you are connected to Meralco, you can use unlimited electricity. In this setup, you can only spend what you make. If you produced 1000W, that’s the only power you can consume. You can lessen your appliance’s usage if sun power production is low. Let us now move to the PART FOUR: SIZING YOUR BATTERY BANK In this part, we will learn new rules.
rule number 2 and rule number 3 In rule number two, you can save so much. so you can only save what your battery capacity is capable of rule number three is “YOU CAN NEVER SPEND ALL THAT YOU SAVE”, we will further discuss this later There are two types of batteries available in the market.
First is the deep cycle battery, just like this for example 200ah battery 12V. Second example is car battery. MOTOLITE What we use in solar is deep cycle battery.
we do not use car battery technically, it will work but we do not use it. WHY? Because its purpose and design to produce massive energy at a short time and charge slowly. When turning on a car engine, we only use massive power once to start the engine starter. That starter is connected to the car battery.
And it charges slowly while we use the car. Unlike in a deep cycle battery, its purpose is lower amount of energy over longer time and it charges quickly.
When we use it in our setup, our power consumption is not massive. Our purpose is to use it for longer time and to charge it quickly. If you will save more in using a car battery, -because it will still work with our solar panel- it may break in a short period of time.
Good bye money. It is better to use a deep cycle battery. There is another type of battery – Lithium which is more expensive but is great because we can use it for a long time compared to the sealed lead acid like this one. SIZING YOUR BATTERY BANK Let us recall our daily power need that we compute earlier which is 1138.4WH we will base here for the size of our battery bank just like on how we determine the perfect size of our solar panel 1138.
4WH divided by 12V because our battery is 12V it’s okay if you will be using 24V but our example here is 12V so let’s use 12V 1138.4WH divided by 12V is equal to 94.9AH it became AH because WH we produce W voltage times voltage times amperes is watts since we have voltage here cancel out the voltage, what remains is the AH 94.9AH or 100AH *round up* We cannot buy a 94.9 AH let us choose a 100AH.
If you still remember rule number three, “YOU CAN NEVER SPEND ALL THAT YOU SAVE” because in this battery we should never discharge below 50% Why? because When we discharge lead acid below 50%, its life is lessen. The charging cycle is lessen. When we discharge this battery, battery life is lessen. Instead of using it for a long time, it is lessen.
So if we have 100AH what we need is 1138WH we will not be using it in 100 hours let us multiply it by two so that we will meet our requirement 1138WH Our usable power is 200AH times 12V is 2400 watt hours we can only use 50% so we divide it by 2 1200WH so now we meet our requirement which is 1138 our battery can now store enough power that we need daily PART FIVE: WIRING YOUR SOLAR PANEL rule number four another rule introduced solar panel to battery should be as close as possible why? because of what we call “wire resistance” in wire resistance, there is a voltage drop the longer the wire run, the more energy is due to resistance the longer the wire we experience voltage drop because the wire has resistance -it is not 100% conductor it also has internal resistance that’s why there is a voltage drop There are two ways to wire our solar panel.
Parallel for example we have 100W solar panel then notice the voltage at Pmax is 18.55V current at Pmax(Imp) is 5.36A when we multiply them it is equal to 99.
43W our example is three of 100W solar panel if we connect them in parallel, what will happen is in parallel connection, current is added as you notice the voltage is 18.55 it’s the same times 16.08A current instead of 5.36 when we multiply them, it’s 298.3 W we sum up the current second way is series If we will connect 3 100W panels in series what will happen is that the voltage will be added 18.
55 + 18.55 + 18.55 is 55.65V times 5.36A current equal to 298.
3W it doesn’t matter if the connection is in series or parallel because we will be getting the same output of 300W Let us look at this illustration. if parallel if our connection will be in parallel, look at the left side we have a single positive and single negative line all the positive and negative will be connected from each of the solar panels in series connection, it is single wired then the positive of solar panel one is connected to the negative of solar panel two and the positive of solar panel two is connected to negative of solar panel three and so on Why do we need to choose between series and parallel? As what is stated in rule number four, solar panel and battery should be as close as possible because we have a voltage drop let us calculate that voltage drop for example we have 10 meters distance from solar panel to battery our cable size is 12 AWG or 12 gauge if you want to be in depth in wire sizing, comment down below and let’s talk about that in the next videos let us talk about wire sizes because it has effects let us take this as an example, let us say that we have 12AWG with same distance of 10 meters look at the voltage drop in the parallel connection it is equivalent to 9% our voltage drop is 1.68 if we have 18.55 voltage from the solar panel when it reach the charge controller or the battery, what remains is 16.
87 because of the voltage drop that is caused by the distance of the solar panel to the charge controller or battery unlike in series the voltage drop is 1% only if your solar panel is connected in series, and we get 55.65V we only had 1% drop so the voltage that the charge controller will receive is 55.09 it’s almost the same with the output only a minimum voltage drop this principle in series connection, if the voltage is high if we are transmitting a high voltage the lesser the voltage drop and that is the same principle in power transmission of power distributor like Meralco notice their high voltage wire they’re using transformer to convert energy to kilovolts then they use a transformer to step down energy to each household imagine the distance of the source of power to every household there will be a huge voltage drop so to compensate that huge voltage drop there are two options, to increase the voltage transmit or increase the size of your cable the wire that you will be using of course if you will be increasing the size of the wire you will spend more money because it is more expensive so you have to consider it in sizing your solar power setup -the distance how far is it? what is the best to use? series connection or parallel?
if plan to have single panel setup you don’t need to think about such if you have a small setup part six part six: SOLAR CHARGE CONTROLLER Its purpose is to control charging of battery basically a sophisticated regulator because we cannot connect the solar panel to the battery directly it might get damaged our solar panel’s output if you notice is not only 12V -it is even higher so that we can charge the battery the source should be higher what controls the charging of the battery is the charge controller there are two type of solar charge controller first, PWM charge controller or pulse width modulation this is an example that one is cheap it has 80% efficiency 12V or 24V system 30A 10 or 20 amp common common model and then what’s good with this is that it’s cheap and you can buy this charge controller for only 400php (8USD) another type is the MPPT or maximum power point tracker this is an example SRLE this is a beautiful item they say that this can reach upto 98% efficiency it’s much much higher compared with the PWM can handle 12V up to 100V depending on model so if we will connect panel in series, we cannot use PWN because it can only handle up to 24V you should use MPPT charge controller is you plan to connect your panels in series because it can handle higher voltage compared to PWM however, MPPT’s drawback is it is not that cheap -it is expensive if PWM is 400php (8USD), MPPT is 4000php (80USD) you need to consider that as well in you setup plan what you will be using if you will be using a single panel, PWM is okay if you will use a single panel, do not use a MPPT but if your setup is multiple panel or a bigger setup, use MPPT or if the distance is near PWM is okay those are the two type of charge controller PWM and MPPT SOLAR CHARGE CONTROLLER SIMPLE EFFICIENCY COMPARISON in PWM let us use a parallel connection as an example once the sun rises let us say at 7 am our solar panel will produce a voltage let us say 4V because the sun just came out in a parallel connection the voltage is the same output will also be the same although current increased however, if your current increased and your voltage is 4V, your PWM charge controller will not start charging because our output is only 4V it has a minimum voltage requirement for it to start charging the battery comparing it to the MPPT SCC we can have a series connection in MPPT because it can handle even higher voltage when the sun rises at 7am each of the panels produces 4V and we have a series connection what will happen? voltage will be added now, we have 12V so that moment the sun rises at 7 am, our MPPT charge controller starts charging our battery compared to the PWM it will wait for the panel to produce 12V 10 or 11V before it starts charging our batteries unlike with MPPT once it has enough voltage from the panel it will start charging the battery we can obviously see the difference with the charge controller’s efficiency let us now move on to part seven which is SOLAR SAFETY using fuse, breaker, automatic or manual disconnect and grounding so from solar panel going to MPPT solar charge controller the output current that we will measure is 15.87A if we are in a series connection if you can still recall with series and parallel connection in designing fuse and breaker we should be using a higher value let us say 20A 20A fuse or breaker in that wire there shouldn’t be 20A flowing because our expected is 15.87A only from MPPT solar charge controller to battery we can observe the same current because that is our input so we can use the same fuse or breaker battery going to inverter the sizing that we compute earlier depending on the appliances that we will be using let us say 500W if you have a 500W inverter we can put a manual disconnect from battery to inverter for safety purposes we can easily disconnect the connection of battery and inverter so the output current that we can get from battery to to inverter is 40A so 500W divided by 12 is 40A so we can use a 50A fuse or breaker because it should be higher and it shouldn’t increase for more than 50 so base on our calculations DIYers for 1kW solar solar off grid setup our daily load of 1138.4WH and this is our usable battery which is 12000WH and our solar output if we have three 100W solar panel so 300 times 5 is 1500 so if we will compute its cost roughly is it 25k to 30k php (600US) there you go a simple setup always remember that solar panel in series or parallel connection but in my example I use a parallel connection because I use a PWM charge controller there is a fuse from solar panel going to charge controller another fuse from charge controller going to battery then battery going to inverter we also put fuse lastly the inverter where we plug our AC devices as of now, I don’t have this kind of setup but if I am going to setup for my house and switch to off grid setup I will be needing this budget this is the typical setup the I will use for now, this is what I have I have a solar backup battery backup solar I have a 100W Zocen solar panel and this is my 12V inverter and I have a battery pack here and a 1000W inverter this one is just a battery backup and my solar panel is not always connected here because I am using my solar panel in my grid tie setup at home but when we do not have much load I connect my battery backup to my solar panel so that is its purpose this is its specifications solar output is 500WH because I have a single 100W panel times 5 sun hours battery is 36AH times 12V 432WH and our load capacity is 250W this is my backup and you can watch my full setup in the “i” button if you have questions just comment down below thank you for watching and don’t forget to like share and subscribe!
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