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solar power

Posted: Thu Jul 27, 2006 4:34 pm
by stylzmovement
I have added up the amperage need to power my transmiter, and my wireless laptop, I have a total of 4 amps.
How will I power this from a solar system with a car battery attach to the system. I will like to use the solar system to charge the battery for night time use; the system will run 24hrs a day ,
this is a total of 4amps per Hour .
can i get a solar system to charge the battery for about 10 hours of night time use?

Posted: Thu Jul 27, 2006 4:43 pm
by pcs
But doesn't the laptop need 19V?

Posted: Thu Jul 27, 2006 5:08 pm
by stylzmovement
i will use an inverter on the laptop

Posted: Thu Jul 27, 2006 6:00 pm
by pcs
Just calculate the total amount of Ah, ampere hours needed.

4A x24h equals ~ 100 Ah. You need to get at least that much
from the solar cells during day. Plus, since the acc
won't store all of the energy and you will loose something
due to losses. Let's say you need about 120 Ah to get
through the day 24/7.

That means solar cells must provide 10A for 12 hours (lets say that's a 12h day)
at a voltage sufficient to charge the acc, that is about 15V at least.

That's ~ 8-10 our 15W solar panels from the website and at least a 60Ah car battery :)

Posted: Thu Jul 27, 2006 11:46 pm
by cliffyk
The inverter for the laptop will be grossly inefficient, output from the solar panels will be reduced on overcast days (dependent on the amount of overcast of course)--so you'll need to have a large enough battery to get through cloudy periods and sufficient generation capacity to recover from extended periods of low output from the panels.

I'd take the numbers Marko provided and add in a 1.5 to 2.0 duty factor.

Posted: Fri Jul 28, 2006 6:42 pm
by stylzmovement
so now the big question.
when will you make a transmitter that will run on a 12 or 24 volt system.
48 volts is to many battries (4)

Posted: Fri Jul 28, 2006 6:59 pm
by pcs
Your battery will be empty in a few minutes, if you want to run a 300W transmitter.

With 50Ah car battery you may get 15 minutes time with one car battery.
Your current draw at 12V would be 40 amps. You would be loosing a lot of power
in the DC connection cables. And it would have to be heavy duty cable.

There is always a reason...

Posted: Sat Jul 29, 2006 1:50 pm
by pcs
We sold one panel and regulator immediately folowing this thread :)

Posted: Sat Jul 29, 2006 2:34 pm
by cliffyk
Cool...

Posted: Sat Jul 29, 2006 3:20 pm
by stylzmovement
so you are saying to run the system at higher voltage , we will use less amprage ?

please explain the meaning or duty cycle?

Posted: Sat Jul 29, 2006 9:36 pm
by cliffyk
Read this, then come back here and ask questions.

You'll need to garner a basic understanding of electrical and electronic engineering before the answers your are likely to receive here will mean anything to you...