Correction on DC CB#2 Current Output of SCC Iscc(out) = PV Array Power (Pr) / Battery Voltage (V) Iscc(out) = 1520W / 48V Iscc(out) = 31.67A DC CB #2 = 31.67A x 1.25, where 1.25 is for buffer DC CB#2 = 40AT 2P DC CB
I have a powmr mppt 60A.manual. suggested air circuit breaker of 100A? Pls help. M using JaSolar (one panel only) isc of 10.33A. Calculated 10.33x 1.25 (some suggested x by another 1.25 for continuous) =approx 16A cb next avail in the market. So should di buy two 16A? Will be using 6mm2(#10AWG)cable
100% clear and understandable solar subjects. DC and AC circuit breakers ( pictures) and wire sizes (pictures) needed to be addressed for full solar off grid system. Thanks
Hei Oliver. I really want to thank you for this short and very precise video on solar hybrid solar system set up. It has summarised almost all the videos i have been watching on UA-cam about the subject. Thanks big time.
I enjoyed your lecture too. Very informative. On the battery sizing, I have noticed you didn't allow for days of autonomy. Just something viewers need to knw for days when you do not have enough sun to fully charge your battery and still require them to sustain the loads. And on the buffer for PV array, thanks for clarifying that, not understood the factor used. Also if reference can be made to the use of factors such as 1.25 i.e. IEC or IEEE. It helps viewers to verify things for themselves.
Thank you so very much for your clear and insightful explanation of an off grid solar system. Without the use of extravagant computer effects, you shared kept me as a viewer interested based on your concise techniques.. if at all possible, it would extremely helpful to understand how the battery and panel strings are impacted by adding another 50% to the daily kWH consumption// I.e more strings and how to safely tie them together. / p.s I’ve subscribed to keep an eye out for other solar power lessons you are willing to share. All the best!
Hello Sir, first of, thanks for subscribing. Regarding solar power setups, during the initial design stage it is advisable to take into account future increase in consumption. For example, if the computed daily consumed power is at 1kW, add some buffer of around 500W to take into account future expansion. Now, if the solar installation is already in place and you want to increase your capacity, just make sure that SCC will be able to take in the increased current and/or voltage from adding solar panels. With regards to inverters, make sure that inverter capacity is still higher than your consumption (especially the surge power). In my line of work where I do initial engineering designs, I always put some buffer on the capacities but at the same time be aware of the client's budget. It seems you have to strike a balance between robustness of your design and overall budget.
Hi Oliver, The calculated battery bank capacity was 245.69Ah but in your calculations we ended up with 4 (12V 250Ah ) batteries giving a total battery bank capacity of 1000Ah which now changed the battery bank capacity instead of 1 (48V 250Ah) battery.
The batteries are connected in series which will produce the same current but different voltage. Meaning, current is the same while voltage changes in series connections. But current changes while voltage remain the same in parallel connections.
Questions? 1. When sizing off-grid batery banks is'nt it common practice to account for outages or days or automomy and what is the apprpriat factror? 2. We mulipled the circuit breaker rating by 1.25 for the first 2 dc circuit breakers. Why not for the last dc and ac breakers?
Hello sir, please see below my answers. 1. For battery autonomy, it really depends on your objective. In my example, i have assumed that the sun will always rise the next day hence, an opportunity to recharge my batteries. You may want to include longer autonomy but for home use, in my opinion, is not necessary not unless you have critical/safety systems (i.e. life support). For commercial applications, there are safety systems that require longer autonomy and these are dictated by national or international rules. For example, an aeronautical obstruction light requires 96 hours of battery autonomy regardless of the main power source. 2. On the 1.25 multiplier, you may or you may not use it, just make sure that the breaker has a higher rating than the computed current flowing through it.
Please how did you determine the system voltage of 48V used in the calculation?, Is it written on the nameplate/specification sheet of the PV panels?. Thank you very much
Assuming I'm designing the system and need an Scc that would be suitable for the system, jow do i determine the Vmax of the Scc as well as its Icc(rated)?. Again, how would you account for the total power of an electric iron when sizing the inverter considering the surge power it produces?
Nice video! It would be useful if you could explain where those number (1.3, 1.25 that I assume are tolerances) come from, as well as accounting for the power consumption of the SCC and the inverter in your calculations
Hi, do you mean you want to put an ATS to toggle between the AC output if the inverter and the AC utility power? Yes you can. It's just a matter of which one will be your main and which one will be the emergency supply. Just take note that if your offgrid system will be the main, there is a possibilty that you will completely deplete your battery before the AC utility kicks in. This might spoil your battery faster.
Thank you for this video. Please the 1.2 and 1.3 value you use sure they are standard values, if not please states reasons why you choose to go with them. Thanks
Hello sir, the 1.2 as multiplier for the PV panels is just a buffer so you are free to modify this. 1.2 means 20% additional capacity. For the 1.3 as multiplier for the surge power, this is an approximate value, if you want to be exact, you can refer to each equipment's datasheet and look for its surge power value.
Using PVsyst software to design a system with the same load capacity of 5.12kwh/day with 5% of LOL , 2days of autonomy, 48v system ...the suggest PV power given to me is 6.13kwp. is this perfect or something is wrong
@@damianinyang7967 Daily consumption (kwh) is the total power over time while PV power is the max power that the panels can produce at any given time. Example, if I have a PV system with capacity of 1.3kw, if it is collecting power from the sun at a steady rate for 5 hours, then the total power produced by my PV system is 1.3kw x 5hrs = 6.5kwh, which is enough to cover my daily power consumption of 5kwh.
@@damianinyang7967 i have not used PVsyst software personally, but there could be differences on our settings, ex. Battery autonomy of 2days, time required to fully charge the battery bank, etc. All these can affect the required PV power.
Hi Mr. Oliver Jay! How can we find your PDF lessons of Off-Grid System Design Calculations?. I am looking forward to your reply as soon as possible. Thanks a lot
Couple of typos in the ilustration, it should be read as 5012W and not 5.012kW other wise the resulting value should be 0.24568, which would not make sense. The final value shown is correct but it would confuse the viewers when they try calculating it. Secondly, the strings (batteries in parallel) mentioned should be calculated as 250Ah / 245.69Ah = 1.017 not the other way around.
Yeah, i should have used 5012W to be consistent and avoid confusion. Anyway, 5012W = 5.012kW. thanks! With regards to the battery strings, the formula is correct (required battery capacity / actual battery capacity). Let's say our requirement is 500 Ah, our battery is spec'd in at 250 Ah, Battery String = 500 Ah / 250 Ah. This means we need 2 strings of this battery.
What is your basis sir in the efficiency of battery sizing? Was it from the nameplate of that certain battery? (Asking because I have a report on load analysis) Thank you sir.
Hi Jays Thanks for the explanation ,I hope it will help many around the world... Kindly will be waiting for videos and have subscribed to your channel' From Nairobi, Kenya
I think it makes sense to partition your system into multiple parts. I guess one smaller battery cycle for the main important things like computer, wifi, light, fan. And one for the nice to have like washing machine, water heater, microwave that can run out of power. Fridges belong to the later because even without power they can hold temperature cold enough for 12 hours (unless your freezer has a lot of meat in it ). One for all seems pretty lazy and not cost efficient.
What's the 1.3, is that the energy lost in the system? Does it mean you're adding 30% of the total watthour to it due to energy lost? Bcoz 5012x 130/100=6515.6 6515.6/5=1301.12 Also, plz how did you choose your multiplier?
hello sir...i have a question about the last AC CB rating, you use 3kW power rated on your computation but the total consumption daily load is more than 5kW and example if all of them use simultaneously their is a chance the breaker will trip off because of the low capacity of the circuit breaker you use....i hope you answer my question...thank you
Hello sir, good day. Please note that the 5kw++ is already the accumulated power consumption for the whole day, as computed in our Step 1. But, at any given time, the maximum power consumption is only 2kW if we consider the surge power (shown in Step 4). 3kW is the maximum power that the inverter can handle, considering this then the AC CB is still safe. Cheers!
Hi thanks for your information I have quetion for protection only we use current breaker we not use voltage circuit breaker?and why for inverter size multiply load by factor 2 or 3 or 1.3?
Hi bro, regarding the load factor, we multiply by 3 or 1.3 to account for the surge current of motor loads. The bigger the motor load, the higher our multiplication factor (x 3). With regards to the protection devices, not sure if I get your question right, I have used current breakers in my example. I have also added isolators to manually cutoff the circuit, I believe this is required by law in some countries. Lastly, the SPD, is for protection against lightning or high surge currents. I hope I answered your question, if not, you can throw a followup question here.
@@OliverJayUA-cam Thanks should use spd in system? CB can use for both purpose? Cutoff and break when greter than 14?and another quetion 1.3 to size pv always we use or depend the efficency of the equipments?and i need cable size calculation have any source ?thanks for every informatoin you share with us🤗🤗
@@bakhshimuhammed1840 Hi Bro, I believe in some parts of the world where lightning strikes are uncommon or if the site already has some kind of lightning arrester or lightning rod, they don't require SPDs in the installation. But, it is a good engineering practice to add in the SPD as this will protect your installation and your home in the event of lightning strike. SPD and breaker are two different things, SPD is meant for high voltage and high frequency sources such as lightning and directs it to the ground. A CB, on the other hand, "breaks" the circuit when a high current flows through it (in events like short circuit or very high load). For wire sizing, it will depend on the resistivity of the material, but you may probably use this: www.paigewire.com/pumpWireCalc.aspx
Did not understand this bit in step 5. Why divide Vmax with Voc ? We already have the number of series panels, calculated in step 2. This is 4 and in series the voltage is 195.2v. The voltage is within rated voltage of the SCC of 200v. We could use an SCC that is closest or something around 200v because there can be an increase in 5 volts during the winter. So to find those in parallel it should be current required to charge the battery bank.
Hi George, good observation. Step 5 is more of like checking if the PV Panel configuration we computed in step 2 falls within the specs of our SCC. In this case, yes. In fact, we still have room for more strings of PV Panels in case you want to charge the battery faster. Not sure why the voltage increases during the winter, we are in a tropical country so we have not experienced it.
@@OliverJayUA-cam Solar panels tend produce more when temperatures are lower hence the max voltage and lower when temperature is higher hence the lower voltage.
Please, I'm a bit confused here, I thought increase in temperature will give rise to high voltage by the panels and vice versa. Please I need clarifications. Thank you!
Calculation of DC CB#03 makes me wonder. Your CB#03 is of 62.5 amps for a 48 volt, 3 kW system. I have been working in solar field, and I have seen people install a 125 amp breaker for 48 volt, 10 kW system, which works perfectly fine. Using your method of calculation, 48 volt, 10kW system needs a CB rated 208 amps. Please clarify. Thank you.
Hi there, thank you for the video! I’m a bit confused with watts (volts x amps)? for eg. my washing machine says 2000 watts is that per hour? I noticed yours is 250watts is yours just a lot more energy efficient than mine or am I calculating it wrong? I appreciate your video it’s very helpful! Thank you
Hi Jess, appreciate the comments. A typical family washing machine has a power rating of around 300-600W. Our washing machine at home is a typical 7.5kg top loader and has a power rating of 450W. If I use it for 1 hour, then my energy consumption is 450Wh, in 2 hours it will be 900Wh, and so on. Wh is just a measure of energy consumption. Am not sure what type of washing machine you have but the power rating seems high.
Thankyou for the reply! It says: “input 2000W -heating” on the label maybe that’s just heating element? It’s an older 7kg washing machine so it should be similar? I’m not sure. I’ll investigate a bit more. Thanks very much!
Hello sir, I am watching from Bangladesh. Your tutorial is good but a point i didn't understand. PV Power = (Daily Consumption/Sun Peak hours)x 1.3 why used 1.3 ? could you please explain here ?
First, thank you so much for your clear explanation! May you help me on how to calculate the the usable load in Watts that keeps the solar arrays charge the battery (lithium batteries) while is being discharged. For example, I have 400W , 12V solar arrays, 300 Ah lithium battery pack, with 500W sine wave. How many Watts load can I draw from this system that can keep my battery being charged while being discharged. Thank you!
Hi Saray, sorry for the delayed response. Been tied up at work. Anyway, to answer your question, the computation presented on the video already covers this since we've already sized the battery and the PV array based on the load consumption (step 1). For the offgrid setup seen in the video, the load takes power from the battery and not directly from the SCC nor PV array. Hope this answers your question. Let me know if I missed something. P.S. If you wan to compute for the Battery Charging Time (H) = Battery Capacity (Ah) / Total Watts of PV Array (W) /Voltage Accross of PV Array (V). From this equation, if you want a faster charging time, you may increase your PV Array but make sure to check if your SCC can still handle it.
@@OliverJayUA-cam Thank you so much! Yes as you mentioned the loads do take the power from the battery that why when the loads consumes draw too much power from the battery, the PV can’t feed the battery well! So I want to know as my example system in my first question. How much power drawn out from battery should balance or keep my battery can be charged up and up! Sorry if my question not clear! Thank you again
@@sarayret6376 Hello Sir, in your example above, 400W , 12V solar arrays, 300 Ah lithium battery pack, with 500W sine wave inverter. In order to charge the battery whilst a load is plugged in, the load should be consuming less than the input power (solar PV array, 400W). This is according to the law of conservation of energy and assuming that all conditions are ideal. In actual, we'll have loses in our system such as efficiency of our equipment, heat loss in wires, etc., so the load consumption should way way less than 400W in order to charge your battery.
That was a fantastic video. Thank you. I have a couple of questions. 1. Because the solar panels would not be able to do a continuous charge due to clouds or something, am I correct that lead-acid batteries suit better than lithium? 2. During the day time when the household equipment draw power while the battery is charging, does the dc-ac converter naturally draw from solar panels first, and draw more from batteries when needed more amps than what the solar panels are providing? If yes, is this safe for the batteries if I use lead-acid? Thanks so much!
Hello sir, please see my answers below: 1. Both lead acid and lithium batteries can be used. Lithium is the better choice in terms of depth of discharge. 2. The load always draws power from the battery
Hi Vincenzo, the system voltage will depend on your preference but also take note that the higher system voltage, the lower is the current flowing through your wires thus allowing you to use smaller wire sizes. But, as a guide, you may use below system voltages wrt power capacity: (1) 12V System Voltage: up to 1199 W (2) 24V System Voltage: 1200W - 2399 W (3) 48V System Voltage: 2400W and above.
@@minnehmugure6641 its the other way round the inverter should be sized based on the system voltage you plan to use. Everyone would opt for a higher voltage because it will reduce the thickness (gauge) of copper wire coming from the solar panel to the inverter. Moreover higher voltage will reduce the size of the battery bank required as well as reduce charge time.
Hi Saju, for DC isolator, you just need to take a look at the voltage rating and current rating. For the Surge protection, take a look at the Uc and Up values. Uc is the maximum continuous operating voltage, if the SPD senses a voltage above this, it becomes active. Up, on the other hand, is the maximum voltage across the SPD when it is active. Up is selected as such that it is below the overvoltage withstand capability of the loads. A typical DC SPD has a Uc of around 500 VDC and a Up of ~2kV.
@@OliverJayUA-cam yung transition ba between dc and ac power walang flow back ng ac power dun sa dc side, sa off grid system? D ba dapat may blocking diode? Just a thought while watching your video.
The 1.3 multiiplier on the solar panel sizing is to compensate for suboptimal conditions like cloudy skies. You can change this multiplier depending on how much buffer you want to add to your system.
@@OliverJayUA-cam thank you so much I learned a lot, now I just wanted to know in the 5st step. 𝐼_𝐶𝐶 = 𝐼_𝑆𝐶 𝑥 𝑁º of string 𝑥 1.25 that 1.25 represents what?
Hello Sir, appreciate the feedback! The 1.25 is a buffer (+25%) when sizing the SCC. It is a good practice to choose a SCC with a higher current capacity than the actual input current (DC current from the Solar Panels) to avoid over current which can damage your SCC.
Hi sir. Good day. I hope you will notice my comment asap, because i badly needed it for my project study. I'm currently stock up at Battery Bank sizing, I'm quite confused on how to acquire the efficiency of the chosen battery rating, I've been searching over the internet for 3 days now and still got nothing.. If you could help me witb this sir, it will be a great help in our project. Thank you
The current after the SCC is not the same as the one flowing in the SCC. The input current depends on the voltage produced from the panels at the moment, the output is calculated for 48 volts, both are for the same wattage.
Hi George, assuming inverter efficiency is 1, you can approximate the run time as T (hr) = Battery Capacity (Ah) x Battery Voltage (i.e. 48V) / Load (W)
@@OliverJayUA-cam Practically inverters do not have an efficiency of 1, considering an efficiency of 95 then it would be (Ah x V)/effciency. Would this be correct ?
Sir ung earth ground po ba kahit sa DC SPD nlng? Khit wala na ring icoconect na ground wire mula sa panel?at kahit hindi kana rin maglagay ng ground sa mga DC CB?safe na safe na po ba ang system at sa tao kahit sa DC SPD lng ung may ground Sir?
Hi Sir, I don't have the excel sheets anymore. But, the formula is simple, for load analysis, you just have to multiply each equipment's Power x Quantity x Usage Duration. Do this for all your equipment type then add them all up to get the daily power consumption.
Hi George, 1.3 is my buffer to compensate for not so optimal conditions like cloudy skies. 1.3 means i added some 30% additional capacity for my PV panels. You may opt to change this how you like.
Hello sir, you are correct. Converters usually refer to devices that convert AC to DC, inverters do the opposite. Sometimes, terms can be interchanged and they are still accepted. DC to AC converter is also an inverter.
Correction on DC CB#2
Current Output of SCC Iscc(out) = PV Array Power (Pr) / Battery Voltage (V)
Iscc(out) = 1520W / 48V
Iscc(out) = 31.67A
DC CB #2 = 31.67A x 1.25, where 1.25 is for buffer
DC CB#2 = 40AT 2P DC CB
I have a powmr mppt 60A.manual. suggested air circuit breaker of 100A? Pls help. M using JaSolar (one panel only) isc of 10.33A. Calculated 10.33x 1.25 (some suggested x by another 1.25 for continuous) =approx 16A cb next avail in the market. So should di buy two 16A? Will be using 6mm2(#10AWG)cable
Noted.
Please I want to know why u used 48V of battery/system voltage and not that of Voc(rated) of the panel since we're looking for Iscc(out).
What will be the effect? Thank u sir!
@@StanleyUchendu This is because the battery system volatge is in 12v/24v/48v, so u must choose any of these system voltages
I haven't seen any other video that comes close to explaining this particular subject so clearly. Thanks for the good work
Glad it was helpful!
Where did you get the 1.3 from?
Exactly the question that threw me off this video… you can't conveniently ignore that factor
It took me almost the whole semester in my final-year undergraduate study to get it all together. Thank you sir. You save my life🙏🏿
The world's best teacher thanks sir
100% clear and understandable solar subjects.
DC and AC circuit breakers ( pictures) and wire sizes (pictures) needed to be addressed for full solar off grid system.
Thanks
Thanks!
Hei Oliver. I really want to thank you for this short and very precise video on solar hybrid solar system set up. It has summarised almost all the videos i have been watching on UA-cam about the subject. Thanks big time.
Thank God!
(Spotted Another Genius on this field... )Thank you Oliver!
Thank you sir. Feedback is very much appreciated!
You took time to explain and educate people on solar sizing and calculation. thank you very much for this video.
Glad it was helpful!
God bless you real good! Thank you so much for the simple explanation.
Welcome po. Thank you din po for your nice comment.
Clear and objective explanation: excellent!!! Thanks...
Thank you sir for the nice feedback.
A marvelous job in explaining the calculations.
Best video on the net for Off grid PV system. Thank you very much for the effort .. 😊
Thank you for sharing. Wery informative and simply explained. you saved me many days!👏👏👏👍👍👍👍👍
Nice and informative video. Tip to all... Listen at 2x speed.
Nice and smooth as well as understanding solar in easy ways, thank you sir
Happy to help
This vid really helps me in designing my off grid solar system.thanks so much!!
You are welcome! :)
Thank you very much Mr.Oliver really you are good teacher
You are very welcome
This is an amazing video. Will start my own solar installer business here at home. Thank you so much.
I enjoyed your lecture too. Very informative. On the battery sizing, I have noticed you didn't allow for days of autonomy. Just something viewers need to knw for days when you do not have enough sun to fully charge your battery and still require them to sustain the loads. And on the buffer for PV array, thanks for clarifying that, not understood the factor used. Also if reference can be made to the use of factors such as 1.25 i.e. IEC or IEEE. It helps viewers to verify things for themselves.
Thank you for this, a very precise explanation! :)
Thank you so very much for your clear and insightful explanation of an off grid solar system. Without the use of extravagant computer effects, you shared kept me as a viewer interested based on your concise techniques.. if at all possible, it would extremely helpful to understand how the battery and panel strings are impacted by adding another 50% to the daily kWH consumption// I.e more strings and how to safely tie them together. / p.s I’ve subscribed to keep an eye out for other solar power lessons you are willing to share. All the best!
Hello Sir, first of, thanks for subscribing.
Regarding solar power setups, during the initial design stage it is advisable to take into account future increase in consumption. For example, if the computed daily consumed power is at 1kW, add some buffer of around 500W to take into account future expansion.
Now, if the solar installation is already in place and you want to increase your capacity, just make sure that SCC will be able to take in the increased current and/or voltage from adding solar panels. With regards to inverters, make sure that inverter capacity is still higher than your consumption (especially the surge power).
In my line of work where I do initial engineering designs, I always put some buffer on the capacities but at the same time be aware of the client's budget. It seems you have to strike a balance between robustness of your design and overall budget.
Hi Oliver,
The calculated battery bank capacity was 245.69Ah but in your calculations we ended up with 4 (12V 250Ah ) batteries giving a total battery bank capacity of 1000Ah which now changed the battery bank capacity instead of 1 (48V 250Ah) battery.
The batteries are connected in series which will produce the same current but different voltage. Meaning, current is the same while voltage changes in series connections. But current changes while voltage remain the same in parallel connections.
Great Video, clear and simple, you are a pro by making it easy. would love to know what is SLD diagram application you have used for electrical DWG.
Excellent video. Really informative & interesting
thank you , its very informative and clear explanation .
Oliver, that was an awesome computation I’ve watch. Can I use this calculation for hybrid solar computation. Thanks for your time.
Questions?
1. When sizing off-grid batery banks is'nt it common practice to account for outages or days or automomy and what is the apprpriat factror?
2. We mulipled the circuit breaker rating by 1.25 for the first 2 dc circuit breakers. Why not for the last dc and ac breakers?
Hello sir, please see below my answers.
1. For battery autonomy, it really depends on your objective. In my example, i have assumed that the sun will always rise the next day hence, an opportunity to recharge my batteries. You may want to include longer autonomy but for home use, in my opinion, is not necessary not unless you have critical/safety systems (i.e. life support). For commercial applications, there are safety systems that require longer autonomy and these are dictated by national or international rules. For example, an aeronautical obstruction light requires 96 hours of battery autonomy regardless of the main power source.
2. On the 1.25 multiplier, you may or you may not use it, just make sure that the breaker has a higher rating than the computed current flowing through it.
@@OliverJayUA-cam Thank you Sir
Please how did you determine the system voltage of 48V used in the calculation?, Is it written on the nameplate/specification sheet of the PV panels?. Thank you very much
Thank you for your best explanation
Glad it was helpful!
Hi sir great and informative video, May i ask what is 1.3 in sizing of pv array? Thanks and more lectures to come
Hi Sir, it is meant to add some buffer capacity to your PV in case of cloudy skies, for example. 1.3 means adding 30% more capacity.
hello friend
video very good
thanks for sharing
like 71
Thanks bro!
Thanks for the insight provided
Nice. Very informative! Thank you for this.
Glad it was helpful!
Great Video, where can I find the documents used?
why multiply by 1.3 when calculating pv power?
Assuming I'm designing the system and need an Scc that would be suitable for the system, jow do i determine the Vmax of the Scc as well as its Icc(rated)?.
Again, how would you account for the total power of an electric iron when sizing the inverter considering the surge power it produces?
Nice video! It would be useful if you could explain where those number (1.3, 1.25 that I assume are tolerances) come from, as well as accounting for the power consumption of the SCC and the inverter in your calculations
Thanks for the suggestion sir!
@@OliverJayUA-cam Don’t mention it! Yours is so far the most comprehensive video I’ve seen on the topic!
hei thanks for the insight , can you put an ATS for the utility power between the in SYSTEM between where AC FROM THE INVERTER IS ...
Hi, do you mean you want to put an ATS to toggle between the AC output if the inverter and the AC utility power? Yes you can. It's just a matter of which one will be your main and which one will be the emergency supply.
Just take note that if your offgrid system will be the main, there is a possibilty that you will completely deplete your battery before the AC utility kicks in. This might spoil your battery faster.
@@OliverJayUA-cam how can i approach the system if i want the solar to be my main without spoiling the batteries
@@joembugua6250 bro, you can go for Hybrid. That way, you'll only use your battery if there's no sun or if there's no power from utility.
Good explanation, what software you used to draw solar panel,inverter, solar charge controller and battery?
Thank you for this video. Please the 1.2 and 1.3 value you use sure they are standard values, if not please states reasons why you choose to go with them. Thanks
Hello sir, the 1.2 as multiplier for the PV panels is just a buffer so you are free to modify this. 1.2 means 20% additional capacity.
For the 1.3 as multiplier for the surge power, this is an approximate value, if you want to be exact, you can refer to each equipment's datasheet and look for its surge power value.
Okay sire thank you .. please why is your daily consumption power 5.012KWH greater than the PV power 1.303 KW....or is KW greater than kWh?
Using PVsyst software to design a system with the same load capacity of 5.12kwh/day with 5% of LOL , 2days of autonomy, 48v system ...the suggest PV power given to me is 6.13kwp. is this perfect or something is wrong
@@damianinyang7967 Daily consumption (kwh) is the total power over time while PV power is the max power that the panels can produce at any given time. Example, if I have a PV system with capacity of 1.3kw, if it is collecting power from the sun at a steady rate for 5 hours, then the total power produced by my PV system is 1.3kw x 5hrs = 6.5kwh, which is enough to cover my daily power consumption of 5kwh.
@@damianinyang7967 i have not used PVsyst software personally, but there could be differences on our settings, ex. Battery autonomy of 2days, time required to fully charge the battery bank, etc. All these can affect the required PV power.
Hi I just want to know why not we include battery in the calculation of load energy consumption? Isn't the battery a load too?
Hi Mr. Oliver Jay!
How can we find your PDF lessons of Off-Grid System Design Calculations?.
I am looking forward to your reply as soon as possible.
Thanks a lot
Can off grid system function without battery storage backup
good day what would it mean when calculating your no of strings one ends up with a frction. is this a miss match or calculations are wrong?
Excellent tutorial.
Couple of typos in the ilustration, it should be read as 5012W and not 5.012kW other wise the resulting value should be 0.24568, which would not make sense. The final value shown is correct but it would confuse the viewers when they try calculating it. Secondly, the strings (batteries in parallel) mentioned should be calculated as 250Ah / 245.69Ah = 1.017 not the other way around.
Yeah, i should have used 5012W to be consistent and avoid confusion. Anyway, 5012W = 5.012kW. thanks!
With regards to the battery strings, the formula is correct (required battery capacity / actual battery capacity). Let's say our requirement is 500 Ah, our battery is spec'd in at 250 Ah, Battery String = 500 Ah / 250 Ah. This means we need 2 strings of this battery.
What is your basis sir in the efficiency of battery sizing? Was it from the nameplate of that certain battery? (Asking because I have a report on load analysis) Thank you sir.
0.65 normally typically
Thanks for sharing the block diagram and equations.
You are welcome!
Fantastic! Useful information. Thank you.
I enjoyed the explanation
where did you get the 1.3?
Hi Jays
Thanks for the explanation ,I hope it will help many around the world...
Kindly will be waiting for videos and have subscribed to your channel'
From Nairobi, Kenya
Thank you!
I think it makes sense to partition your system into multiple parts. I guess one smaller battery cycle for the main important things like computer, wifi, light, fan. And one for the nice to have like washing machine, water heater, microwave that can run out of power. Fridges belong to the later because even without power they can hold temperature cold enough for 12 hours (unless your freezer has a lot of meat in it ). One for all seems pretty lazy and not cost efficient.
What's the 1.3, is that the energy lost in the system?
Does it mean you're adding 30% of the total watthour to it due to energy lost?
Bcoz 5012x 130/100=6515.6
6515.6/5=1301.12
Also, plz how did you choose your multiplier?
hello sir...i have a question about the last AC CB rating, you use 3kW power rated on your computation but the total consumption daily load is more than 5kW and example if all of them use simultaneously their is a chance the breaker will trip off because of the low capacity of the circuit breaker you use....i hope you answer my question...thank you
Hello sir, good day. Please note that the 5kw++ is already the accumulated power consumption for the whole day, as computed in our Step 1. But, at any given time, the maximum power consumption is only 2kW if we consider the surge power (shown in Step 4). 3kW is the maximum power that the inverter can handle, considering this then the AC CB is still safe. Cheers!
@@OliverJayUA-cam okay sir thank you
You are welcome sir
..in the shown diagram is in serial pv connection this means for the batteries. Which is the correct one for the batteries, serial or parallel?
Hello sir, as per the calculation, the batteries will be connected in series.
Hi thanks for your information I have quetion for protection only we use current breaker we not use voltage circuit breaker?and why for inverter size multiply load by factor 2 or 3 or 1.3?
Hi bro, regarding the load factor, we multiply by 3 or 1.3 to account for the surge current of motor loads. The bigger the motor load, the higher our multiplication factor (x 3).
With regards to the protection devices, not sure if I get your question right, I have used current breakers in my example. I have also added isolators to manually cutoff the circuit, I believe this is required by law in some countries. Lastly, the SPD, is for protection against lightning or high surge currents.
I hope I answered your question, if not, you can throw a followup question here.
@@OliverJayUA-cam Thanks should use spd in system? CB can use for both purpose? Cutoff and break when greter than 14?and another quetion 1.3 to size pv always we use or depend the efficency of the equipments?and i need cable size calculation have any source ?thanks for every informatoin you share with us🤗🤗
@@bakhshimuhammed1840 Hi Bro, I believe in some parts of the world where lightning strikes are uncommon or if the site already has some kind of lightning arrester or lightning rod, they don't require SPDs in the installation. But, it is a good engineering practice to add in the SPD as this will protect your installation and your home in the event of lightning strike. SPD and breaker are two different things, SPD is meant for high voltage and high frequency sources such as lightning and directs it to the ground. A CB, on the other hand, "breaks" the circuit when a high current flows through it (in events like short circuit or very high load).
For wire sizing, it will depend on the resistivity of the material, but you may probably use this: www.paigewire.com/pumpWireCalc.aspx
@@OliverJayUA-cam thanks
These are super interesting and well-calculated lectures thanks so much. However, how can I get parts 1, 2, and 3. Thanks
Which software you used to draw the schematic
Did not understand this bit in step 5. Why divide Vmax with Voc ? We already have the number of series panels, calculated in step 2. This is 4 and in series the voltage is 195.2v. The voltage is within rated voltage of the SCC of 200v. We could use an SCC that is closest or something around 200v because there can be an increase in 5 volts during the winter. So to find those in parallel it should be current required to charge the battery bank.
Hi George, good observation. Step 5 is more of like checking if the PV Panel configuration we computed in step 2 falls within the specs of our SCC. In this case, yes. In fact, we still have room for more strings of PV Panels in case you want to charge the battery faster.
Not sure why the voltage increases during the winter, we are in a tropical country so we have not experienced it.
@@OliverJayUA-cam Solar panels tend produce more when temperatures are lower hence the max voltage and lower when temperature is higher hence the lower voltage.
@@gtag174 ah yes yes. Thanks!
Please, I'm a bit confused here, I thought increase in temperature will give rise to high voltage by the panels and vice versa. Please I need clarifications. Thank you!
if i have 1000V DC/AC converter with Icharge/discharge=240A and battery 48V, 250Ah is DC CD#3 set to 240A?
I have a 1620AH , 2v batter, can I get a 2v inverter? Also how did you come about the current rating of the inverter
Calculation of DC CB#03 makes me wonder. Your CB#03 is of 62.5 amps for a 48 volt, 3 kW system. I have been working in solar field, and I have seen people install a 125 amp breaker for 48 volt, 10 kW system, which works perfectly fine. Using your method of calculation, 48 volt, 10kW system needs a CB rated 208 amps. Please clarify.
Thank you.
Hi there, thank you for the video! I’m a bit confused with watts (volts x amps)? for eg. my washing machine says 2000 watts is that per hour? I noticed yours is 250watts is yours just a lot more energy efficient than mine or am I calculating it wrong? I appreciate your video it’s very helpful!
Thank you
Hi Jess, appreciate the comments. A typical family washing machine has a power rating of around 300-600W. Our washing machine at home is a typical 7.5kg top loader and has a power rating of 450W. If I use it for 1 hour, then my energy consumption is 450Wh, in 2 hours it will be 900Wh, and so on. Wh is just a measure of energy consumption.
Am not sure what type of washing machine you have but the power rating seems high.
Thankyou for the reply! It says:
“input 2000W -heating”
on the label maybe that’s just heating element? It’s an older 7kg washing machine so it should be similar? I’m not sure. I’ll investigate a bit more. Thanks very much!
@@Lilyequestrain 2000W could be the drier part. Ours is only wash and spin dry.
some washing machines has build in electric coil for water heating, thats why its power will be higher.
Hi. It's okay to use a a 3kw inverter rating for a 5 kwh power daily consumption?
Will this system run the appliances and charge the batteries at the same time?
Hello sir, I am watching from Bangladesh. Your tutorial is good but a point i didn't understand.
PV Power = (Daily Consumption/Sun Peak hours)x 1.3
why used 1.3 ? could you please explain here ?
Hello sir, 1.3 is for additional capacity to compensate for cloudy skies. You can remove this if you don't want to include the extra capacity.
Hello, good presentation however on the calculation of PV the constant 1.3 represent what. i.e PV = (Daily power consumption/Sun Peak Hours) x 1.3
Hello, I was just wondering if you have the link of the references for the formulas used in the video. If there is, it would be very much appreciated.
First, thank you so much for your clear explanation! May you help me on how to calculate the the usable load in Watts that keeps the solar arrays charge the battery (lithium batteries) while is being discharged. For example, I have 400W , 12V solar arrays, 300 Ah lithium battery pack, with 500W sine wave. How many Watts load can I draw from this system that can keep my battery being charged while being discharged. Thank you!
Hi Saray, sorry for the delayed response. Been tied up at work. Anyway, to answer your question, the computation presented on the video already covers this since we've already sized the battery and the PV array based on the load consumption (step 1). For the offgrid setup seen in the video, the load takes power from the battery and not directly from the SCC nor PV array. Hope this answers your question. Let me know if I missed something.
P.S. If you wan to compute for the Battery
Charging Time (H) = Battery Capacity (Ah) / Total Watts of PV Array (W) /Voltage Accross of PV Array (V). From this equation, if you want a faster charging time, you may increase your PV Array but make sure to check if your SCC can still handle it.
@@OliverJayUA-cam Thank you so much! Yes as you mentioned the loads do take the power from the battery that why when the loads consumes draw too much power from the battery, the PV can’t feed the battery well! So I want to know as my example system in my first question. How much power drawn out from battery should balance or keep my battery can be charged up and up! Sorry if my question not clear! Thank you again
@@sarayret6376 Hello Sir, in your example above, 400W , 12V solar arrays, 300 Ah lithium battery pack, with 500W sine wave inverter. In order to charge the battery whilst a load is plugged in, the load should be consuming less than the input power (solar PV array, 400W). This is according to the law of conservation of energy and assuming that all conditions are ideal. In actual, we'll have loses in our system such as efficiency of our equipment, heat loss in wires, etc., so the load consumption should way way less than 400W in order to charge your battery.
@@OliverJayUA-cam will it help by Addition of PV to cover the lost?
@@agusmuharam6491 Hi sir, yes. Just make sure that the voltage and current at the SCC input is still within the acceptable range.
Hi Sir, What did you use to draw your diagram
Hi sir, i used microsoft visio
Good guide dude!
Thank you kind man for share you knowledge❤
Nice video, could you please recommend a DC/AC Converter Brand/Model? thank you
Hello sir, you can check Snadi brand. It's quite commonly used for solar projects.
Can u make an Air conditioner using Sola Off grid video ?
Hi Sir, thank you for the suggestion. Will try to do one once this pandemic is over and when I get back home.
That was a fantastic video. Thank you.
I have a couple of questions.
1. Because the solar panels would not be able to do a continuous charge due to clouds or something, am I correct that lead-acid batteries suit better than lithium?
2. During the day time when the household equipment draw power while the battery is charging, does the dc-ac converter naturally draw from solar panels first, and draw more from batteries when needed more amps than what the solar panels are providing? If yes, is this safe for the batteries if I use lead-acid?
Thanks so much!
Hello sir, please see my answers below:
1. Both lead acid and lithium batteries can be used. Lithium is the better choice in terms of depth of discharge.
2. The load always draws power from the battery
Hi Jay, on Step 3: you assume a system Voltage of 48 (to calculate the number of batteries in 1 string , i.e. 48/12 = 4) . Why 48 ? thanks
Hi Vincenzo, the system voltage will depend on your preference but also take note that the higher system voltage, the lower is the current flowing through your wires thus allowing you to use smaller wire sizes. But, as a guide, you may use below system voltages wrt power capacity: (1) 12V System Voltage: up to 1199 W (2) 24V System Voltage: 1200W - 2399 W (3) 48V System Voltage: 2400W and above.
@@OliverJayUA-cam Can you say the system voltage is determined by the inverter you use?
@@minnehmugure6641 its the other way round the inverter should be sized based on the system voltage you plan to use. Everyone would opt for a higher voltage because it will reduce the thickness (gauge) of copper wire coming from the solar panel to the inverter. Moreover higher voltage will reduce the size of the battery bank required as well as reduce charge time.
48V for 5000+ watts. If we need less power 2400W, we use 24V.
Excellent
Thanks
Hello sir can you please give us the name of the software we use to design this drawing ( to presente pv module, battery, converter,...)
Hello sir, i only used microsoft visio for my diagrams.
What is the selection criteria and rating for DC SPD and DC isolator
Hi Saju, for DC isolator, you just need to take a look at the voltage rating and current rating.
For the Surge protection, take a look at the Uc and Up values. Uc is the maximum continuous operating voltage, if the SPD senses a voltage above this, it becomes active. Up, on the other hand, is the maximum voltage across the SPD when it is active. Up is selected as such that it is below the overvoltage withstand capability of the loads. A typical DC SPD has a Uc of around 500 VDC and a Up of ~2kV.
How about the wire sizes?
Hi Peter, this should be a good reference: www.paigewire.com/pumpWireCalc.aspx?AspxAutoDetectCookieSupport=1
@@OliverJayUA-cam yung transition ba between dc and ac power walang flow back ng ac power dun sa dc side, sa off grid system? D ba dapat may blocking diode? Just a thought while watching your video.
well done. please can you please help me with solar energy design software?
When you size, Solar Panel Power=(Daily Consumption *Sun Peakhour)/1.3
Here 1.3 is what?
Please explain
in the part of calculating the capacity of the solar system that 1.3 is related to what?
The 1.3 multiiplier on the solar panel sizing is to compensate for suboptimal conditions like cloudy skies. You can change this multiplier depending on how much buffer you want to add to your system.
@@OliverJayUA-cam
thank you so much I learned a lot, now I just wanted to know in the 5st step. 𝐼_𝐶𝐶 = 𝐼_𝑆𝐶 𝑥 𝑁º of string 𝑥 1.25 that 1.25 represents what?
Hello Sir, appreciate the feedback! The 1.25 is a buffer (+25%) when sizing the SCC. It is a good practice to choose a SCC with a higher current capacity than the actual input current (DC current from the Solar Panels) to avoid over current which can damage your SCC.
thank you so much
You are welcome sir
Hi sir. Good day. I hope you will notice my comment asap, because i badly needed it for my project study. I'm currently stock up at Battery Bank sizing, I'm quite confused on how to acquire the efficiency of the chosen battery rating, I've been searching over the internet for 3 days now and still got nothing.. If you could help me witb this sir, it will be a great help in our project. Thank you
Hello sir, it is usually indicated in the datasheet. If not, you may consult the manufacturer or your supplier, they should be able to help.
The current after the SCC is not the same as the one flowing in the SCC. The input current depends on the voltage produced from the panels at the moment, the output is calculated for 48 volts, both are for the same wattage.
Hi Martin, yes, you are correct! Thanks for pointing it out.
Why would you need such a high voltage coming from your panels?
why did you multiply by 1.3 at 8:00
Yes, thanks
You're welcome
So how do we calculate the run time when the grid is off.
Hi George, assuming inverter efficiency is 1, you can approximate the run time as T (hr) = Battery Capacity (Ah) x Battery Voltage (i.e. 48V) / Load (W)
@@OliverJayUA-cam Practically inverters do not have an efficiency of 1, considering an efficiency of 95 then it would be (Ah x V)/effciency. Would this be correct ?
Hi George, it will then be Battery Capacity (Ah) x Battery Voltage (i.e. 48V) x Efficiency (i.e 0.95) / Load (W)
@@OliverJayUA-cam Thanks you.
NP
Sir ung earth ground po ba kahit sa DC SPD nlng? Khit wala na ring icoconect na ground wire mula sa panel?at kahit hindi kana rin maglagay ng ground sa mga DC CB?safe na safe na po ba ang system at sa tao kahit sa DC SPD lng ung may ground Sir?
Where dd u get ur formulars I need to quote it in my project
Hello sir, I attended some short courses on solar. Some concepts can be learned in school and during actual project implementations.
Many thanks for valuable study , appreciate if you can share the excel sheets
Hi Sir, I don't have the excel sheets anymore. But, the formula is simple, for load analysis, you just have to multiply each equipment's Power x Quantity x Usage Duration. Do this for all your equipment type then add them all up to get the daily power consumption.
Wow this realy smart idea good job
Thank you! Cheers!
Good lesson
You say in the video it is in parralelle co. Ection but your picture is in series ,?????
thanks 👍👍
What is the constant 1.3 got to do here in step 2 ?
Hi George, 1.3 is my buffer to compensate for not so optimal conditions like cloudy skies. 1.3 means i added some 30% additional capacity for my PV panels. You may opt to change this how you like.
@@OliverJayUA-cam Ah yes, i suspected it.
Thank you for sharing
My pleasure
Sir tanong lng po kung ano po ibigsabihin kapag sinabi na kunware 4kW grid tie system.ung solar panel po ba tinutukoy na 4kW sir?
Hello sir, in my opinion, it should pertain to the grid-tie inverter size and not the panel.
Is it Converter or an Inverter? I thought Solar Charge controller act as an converter while an Inverter transform DC voltage to AC voltage? Isn't it?
Hello sir, you are correct. Converters usually refer to devices that convert AC to DC, inverters do the opposite. Sometimes, terms can be interchanged and they are still accepted. DC to AC converter is also an inverter.