Excellent. Well-spoken, knowledgeable, understandable presentation. No fluff, some good advice and no sales pitch. Wish I found your channel a lot sooner.
Brilliant! Thank you Smart Energy Lab for sharing this video. In Papua New Guinea we do our calculations based on 5 daylight hours due to more sunlight because we are much closer to the Equator. Thank you again. Greetings from Madang, Papua New Guinea!
Very enjoyable as I start my solar PV/Battery journey here in southern Illinois. As a start after receiving my first PV estimates, I UPSIZED each proposal. Most vendors started with a PV system that covered about 86% of my annual usage. I kept increasing the number of 405-watt panels until I got to 125% and was still within my budget. Adding batteries next year so am hoping for more choices like the Tesla Power Wall 3 and lower prices. Again thanks for the lesson and valuable information.
On part D, you considered that all the power required in a day will be drawn from the batteries. This is not the normal case because during the day, you can use power directly from the solar panels. The batteries are required to supply power when the solar panels are not generating and that cannot be the whole day. You can increase the battery size to add days of autonomy if you wish.
Are you not going to adjust the size of the pv system or the power capacity once the day of autonomy goes beyond. coz i think the charging of battery will also be affected seems on the computation is good only for the 9000wp.
Hi Glen, thank you for the lessons. I have a question, for a stand alone system without backup system, do we need to consider the amount of energy required to charge the battery when sizing the PV? if yes, how should we do it efficiently? Thank you.
The sizing calculations are just to confirm PV array and battery capacity. Sizing of a.c. inverter would be based on maximum coincidental load and d.c. coupled charge controller on maximum PV input voltage and maximum output current from the array.
Excellent video thanks ! Please, any explanation why battery voltage is set to 52 V ? is it something special about NZ ? In my country, common battery system voltages for solar systems are multiples of 12V and include 12V, 24V, 48V, and sometimes higher multiples such as 72V or 96V.
Mostly it’s the coulombic efficiency of charging at a higher potential than discharging. Check out the Battery Test Centres real world results. batterytestcentre.com.au/project/lithium-ion/
Imagine: this example shows 36kWh battery ESS for a home using only 9kWh/day. So a home using 36kWh per day needs a battery ESS of 144kWh ! Expensive. Some national electrical codes will not permit battery storage above 20kWh meaning they basically BAN off grid solar, in the name of safety.
My system was specified like this by the specialist power supplier I bought from and it is a DISASTER! It can fail and shuts down when demand is at a peak even though battery bank is like 90% full. This is due to the batteries not being able to supply high loads because 1/. there aren't enough of them to spread the load out 2/. they are lead-acid type and not suited to high loads. I have a backup generator and so chose to have only two days autonomy to reduce the costs (and the embodied CO2 emissions). The result is too small a battery bank to do the job on even 1 day. Maybe li-ion would have been ok but even they must have their limits. So in A. of your calculations you need to consider not just the TOTAL Ah demand but also the MAXIMUM power demand at any one time and check if the batteries can handle this.
You are correct - this formula is for sizing energy storage and PV generation only. For sizing of the inverter and maximum discharge rate of the battery system you would need to consider the maximum coincidental demand on the battery from the loads. I'll make a follow up video on sizing for maximum demand soon.
The first losses are on the load side and are used to calculate days of autonomy, the second time these load side losses are included is to accommodate the PV sizing to replace the lost energy. Have a look at Appendix A in AS/NZS 4509.2 and you'll see the same logic.
Excellent. Well-spoken, knowledgeable, understandable presentation. No fluff, some good advice and no sales pitch. Wish I found your channel a lot sooner.
Thank you Arthur. You've made my day!
Brilliant! Thank you Smart Energy Lab for sharing this video. In Papua New Guinea we do our calculations based on 5 daylight hours due to more sunlight because we are much closer to the Equator. Thank you again. Greetings from Madang, Papua New Guinea!
Thank you! Yes, Papua New Guinea would have a much higher solar radiation number.
Nice, simple, and straight to the point. Great job, buddy!
Very enjoyable as I start my solar PV/Battery journey here in southern Illinois. As a start after receiving my first PV estimates, I UPSIZED each proposal. Most vendors started with a PV system that covered about 86% of my annual usage. I kept increasing the number of 405-watt panels until I got to 125% and was still within my budget. Adding batteries next year so am hoping for more choices like the Tesla Power Wall 3 and lower prices. Again thanks for the lesson and valuable information.
Hello. I'm a solar installer watching from Mauritius.
On part D, you considered that all the power required in a day will be drawn from the batteries. This is not the normal case because during the day, you can use power directly from the solar panels. The batteries are required to supply power when the solar panels are not generating and that cannot be the whole day. You can increase the battery size to add days of autonomy if you wish.
Thank you so much! Such a concise explanation, and I completely agree with you about doubling the number of modules.
Well, for the pure Off Grid system then have to be added more PV capacity in order to recharge the battery while PV feed the load connected
Are you not going to adjust the size of the pv system or the power capacity once the day of autonomy goes beyond. coz i think the charging of battery will also be affected seems on the computation is good only for the 9000wp.
Hi Glen, thank you for the lessons. I have a question, for a stand alone system without backup system, do we need to consider the amount of energy required to charge the battery when sizing the PV? if yes, how should we do it efficiently? Thank you.
Ok, im slow. still not getting it. I have two 12v 280Ah batteries and four 550w panels. What size charge controller and inverter do i need?
The sizing calculations are just to confirm PV array and battery capacity. Sizing of a.c. inverter would be based on maximum coincidental load and d.c. coupled charge controller on maximum PV input voltage and maximum output current from the array.
Excellent video thanks ! Please, any explanation why battery voltage is set to 52 V ? is it something special about NZ ?
In my country, common battery system voltages for solar systems are multiples of 12V and include 12V, 24V, 48V, and sometimes higher multiples such as 72V or 96V.
In my example I used lithium ion batteries which have different cell voltages to lead-acid. Typically 52-54 V is nominal for a cell pack.
Love a good theory lesson! Top vid mate!
Can you send the link on how to get the AS/NZS 4509.2 Standard book🙏
You can purchase it from Standards New Zealand www.standards.govt.nz/ (cheap) or from Standards Australia (expensive).
@@SmartEnergyLab thankyou
Thanks for sharing 👍
Excellent overview and well delivered, thank you! + SUBSRIBED, keep up the great work!
nice sir , best regard
95% Round trip for lithium? Where do you think you're losing that much? i.e. 5% loss. Heat or loss of gases?
Mostly it’s the coulombic efficiency of charging at a higher potential than discharging. Check out the Battery Test Centres real world results. batterytestcentre.com.au/project/lithium-ion/
Imagine: this example shows 36kWh battery ESS for a home using only 9kWh/day.
So a home using 36kWh per day needs a battery ESS of 144kWh ! Expensive.
Some national electrical codes will not permit battery storage above 20kWh meaning they basically BAN off grid solar, in the name of safety.
How accurate are these compared to an iterative method for pv sizing?
Thanks for the question. Can you elablorate on what you mean by "iterative" - can you show an example please?
Sorry,but real and total autonomy-Offgrid,have no price!🔥
My system was specified like this by the specialist power supplier I bought from and it is a DISASTER!
It can fail and shuts down when demand is at a peak even though battery bank is like 90% full. This is due to the batteries not being able to supply high loads because 1/. there aren't enough of them to spread the load out 2/. they are lead-acid type and not suited to high loads. I have a backup generator and so chose to have only two days autonomy to reduce the costs (and the embodied CO2 emissions). The result is too small a battery bank to do the job on even 1 day. Maybe li-ion would have been ok but even they must have their limits.
So in A. of your calculations you need to consider not just the TOTAL Ah demand but also the MAXIMUM power demand at any one time and check if the batteries can handle this.
You are correct - this formula is for sizing energy storage and PV generation only. For sizing of the inverter and maximum discharge rate of the battery system you would need to consider the maximum coincidental demand on the battery from the loads. I'll make a follow up video on sizing for maximum demand soon.
Wrong. You are doing double accounting. Using the DC-AC conversion and wiring losses TWICE. 1:50 and 6:12.
The first losses are on the load side and are used to calculate days of autonomy, the second time these load side losses are included is to accommodate the PV sizing to replace the lost energy. Have a look at Appendix A in AS/NZS 4509.2 and you'll see the same logic.
@@SmartEnergyLab true.