Eric Lee's posts

Posted by Eric Lee on Mar 27, 2011 10:40 am

#1 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > About the Inverter
Hi all,

1) What is the difference between a grid-tie inverter and an off-grid inverter?  What components they both have or don't have?

2) For a off-grid inverter, is there a difference in mega wattage size inverter or under 1000W size inverter?

3) ‘re there any isolation need to protect the inverter from the interferences from outside? 

 

are there any book about the above mentioned inverter?

 

Thanks and Best Regards,

Eric Lee
 

Posted by Eric Lee on Mar 27, 2011 10:06 am

#2 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Calculation Confirmation of the Solar Panel Power in the DC Lighting System
Dear Mr. Thomas Anderson,

Thanks for your confirmation. 

Best Regards,
Eric Lee
 

Posted by Eric Lee on Mar 26, 2011 02:18 am

#3 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Which configuration should I choose
Hi all,
Here is my project:
My customer currently use 400W halogen lamps at 240V A.C, we have persuaded them to change to use LED floodlight(240V A.C,56W)with solar panel.  Solar Panel is the idea from my customer.  Here is the problem:

In case for a continuously cloudy day, the solar-LED system have to be automatically switch to the mains (240V A.C), so which configuration I should choose:

1a) Change the voltage in of the LED floodlight to 24V D.C and
1b) place an converter (from 240V to 24V D.C) between the mains to the LED floodlight in case not enough solar power supply is detected?  (is there a charger controller equip this feature?)

2) Is there a charge controller have a function that when not enough solar power is detected, the battery can automatically draws current from the mains?

3) Or just add an inverter between the battery and the 240V A.C. in of the LED floodlight, and once not enough solar power is detected by the charger, the mains could supply current to the LED floodlight automatically, in order to doing that, what component is needed?


Pls kindly advise.
Thanks and Best Regards,
Eric Lee

 

Posted by Eric Lee on Mar 25, 2011 09:41 am

#4 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Calculation Confirmation of the Solar Panel Power in the DC Lighting System
Dears,

Here is:
Off Grid
Sunshine Duration: 4hr per day
System: 24V DC, 48W
Operating hr = 10 hr

How much solar panel power needed?

Power needed in the system should be: = 48 X 10 = 480Wh
80% efficiency assume: =480/0.8 = 600
Power needed to be generated in the solar panel in one hr
= 600Wh/4
= 150Wh

Imply that I have to use 150W solar panel, right?

However I get another calcuation from someone, and I am not sure it is wrong or not:

Current is calculated first: 48W/24V = 2A;
Then go to the current consumption:  = 2A X 10 = 20Ah;
Then divide by sunshine hr = 20Ah/4 = 5A;
Power needed to be generated in the 34V panel  = 5 X 34
                                               = 170W
80% efficiency assume = 170/0.8 = 212W

So which one is right? or both are wrong?

Thanks and Best Regards,
Eric Lee
 

Posted by Eric Lee on Mar 23, 2011 08:26 am

#5 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: How many pcs of the 120W solar panel do I need?
Dear Mr.Thomas Anderson,

I understand now.  Thanks for your help.

Best Regards,
Eric Lee
 

Posted by Eric Lee on Mar 22, 2011 11:52 pm

#6 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: How many pcs of the 120W solar panel do I need?
Dear Mr. Tom Mayrand and Thomas Anderson,

Thanks for you pointing out that the current in the 120W 34V solar panel is  = 120/34 = 3.529A

And right now it need 24.7A, so the no. of solar panel needed should be = 24.7/3.529 = 7 pcs in Parallel, right?

So the total no. of the 120W solar panel to supply to this system (14A, 240V) for 6 hrs is 7 pcs?

This is of course not the answer as you have discussed so far, but pls kindly help me to figure out the key point or in which part there is error in the calculation......

I understand there is a difference in the 240V AC and 12V DC, but in which step I have lost in this calcuation can that can compensate this difference, pls show me....

thks.
 

Posted by Eric Lee on Mar 22, 2011 10:23 am

#7 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: How many pcs of the 120W solar panel do I need?
Thanks to all your reply.

The loading operating voltage is 240V AC.
And 34V is the solar panel opeating voltage.

But what's wrong in the logic of the calculation?

I used the Equation of Power = voltage X current:
Power need to be created in the solar panel = 34 X 24.7 = 840W

Is the figure 24.7 wrong? ("current need to be created in the solar panel")

I calculate the 24.7 based on the following logic:
 
Current capacity of the loading per day: 14A X 6Hr = 84AH
Current need to be created in the solar panel:
84AH/3.4hr = 24.7A

1) Could you pls kindly point out that which part in the logic have problem?

2) Would it be too long for the payback period either 77 pcs 120W or 36 pcs 210W for the 25.2KWH AC loading?

Thanks and Best Regards,
Eric Lee

 

Disclaimer and Disclosure

The Alternative Energy Store, Inc reserves the right, within its sole discretion, to refuse or delete any posting or portion thereof, or terminate or block the access to this forum.

The opinions and statements posted on this forum are the opinions and statements of the person posting same, and do not constitute the opinion or act of the Alternative Energy Store, Inc (AltE). The Alternative Energy Store, Inc does not endorse or subscribe to any particular posting. No posting shall be construed as the act or opinion of the Alternative Energy Store, Inc.

Click here for BBB Business Review

McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
Desktop Website | Mobile Website

Share

Click on an icon to share! If you don't see the method you want, hover over the orange "+".

Feedback

What can we do to help you?

Please enter a summary
Sorry, the copyright must be in the template.
Please notify this forum's administrator that this site is using an ILLEGAL copy of SMF!
Copyright removed!!