how to calculate nominal voltage for pv system

[gehad]

Dear all;
Please, I want to know if have solar panel of 250w & its Vmp is 30.5v and System DC voltage is 24V & batteries 12 v
how to calculate the nominal voltage ?

[Sunking]

Huh? Nominal voltage of a battery is its rated voltage. A 12 volt battery nominal voltage is 12 volts. Its operating voltage range is 10.5 to 14.5 volts.

[gehad]

Huh? Nominal voltage of a battery is its rated voltage. A 12 volt battery nominal voltage is 12 volts. Its operating voltage range is 10.5 to 14.5 volts.

ok . For examples if batteries voltage is 48V , What should be the pv operating and max. voltage ?

[Sunking]

ok . For examples if batteries voltage is 48V , What should be the pv operating and max. voltage ?

Minimum is 62 volts up to 600 volts.

[Mike90250]

Sunking, you ARE merciless! We love you.

gehad - the question that you want to be asking, is What voltage is required to recharge a 48V battery bank. Then you will get a useable answer.

You also need to learn about Charge Controllers, and their 2 basic types
PWM (about 70% efficient)
MPPT (about 95% efficient)

We had a MPPT vs PWM FAQ somewhere, but I can't find it right now.

[Sunking]

Sunking, you ARE merciless!

Ok then 18 volts for each 12 volt of battery minimum requirement.

[solarIdiot]

We had a MPPT vs PWM FAQ somewhere, but I can't find it right now.

Might be what Mike was referencing http://www.solarpaneltalk.com/showth...PT-Controllers

That's by far nicer than what I wanted to type out after seeing the OPs username.

[Sunking]

Might be what Mike was referencing http://www.solarpaneltalk.com/showth...PT-Controllers

Yes it is a Readers Digest version of a Sticky I made that Mike paraphrased from memory. I deleted because of all of the replies and off topic chatter that diluted from the subject material.

[solarIdiot]

Yes it is a Readers Digest version of a Sticky I made that Mike paraphrased from memory. I deleted because of all of the replies and off topic chatter that diluted from the subject material.

I was wondering why you asked it be deleted.

Thanks for taking the time on those stickies both you and Mike. When ever I have a question I check em. I usually find the answer with out having to bother anyone too!

Also thank you for your honesty, I happen to like not being lied to even if I'm not going to like the answer.

[Sunking]

Thanks for taking the time on those stickies both you and Mike.

You are welcome.

Also thank you for your honesty, I happen to like not being lied to even if I'm not going to like the answer.

I am no salesman or politician. I wished I had JFK charisma. He told good half truths that worked in reality. He kind of told you what you wanted to hear to like him then screwed you over with the truth and medicine the country needed at the time. Just ask Castro, Marilyn, and Jackie. They all got screwed by JFK and liked it.

[solarIdiot]

and Jackie. They all got screwed by JFK and liked it.

hahaha damn you are the King.

[gehad]

Clearly, I have PV Module with the following specs:
P max = 250 W
I mp = 8.22 A
V mp = 30.4 V
I sc = 8.73 A
V oc = 37.1 V

how to calculate the nominal module voltage please?

another question please, how to make AC variable load to test the PV system ?

[Sunking]

Clearly, I have PV Module with the following specs:
P max = 250 W
I mp = 8.22 A
V mp = 30.4 V
I sc = 8.73 A
V oc = 37.1 V

how to calculate the nominal module voltage please?

Vmp

[green]

Vmp

People usually answer their own questions, they just don't realize it.

[inetdog]

how to calculate the nominal module voltage please?

For a panel designed for use with an MPPT CC or GTI the nominal voltage is Vmp, as stated. And the nominal current would be the nominal wattage divided by Vmp, which is equal to Imp.
For panels intended for use with as PWM CC to charge batteries, the "nominal" voltage of the panel is sometimes taken to be the nominal voltage of the battery bank it is to be used with. Using that convention, a panel with Vmp=18 may be called a "12 volt panel." Similarly, a panel with Vmp=36 may be called a "24 volt panel".
In that case, the nominal current through a PWM controller will be wattage divided by Vmp and not voltage divided by 12v.
When writing down, calculating with, or referring to the nominal voltage of a panel, you need to make it clear which of the two conventions you are following.