Solar energy

[Michel Szulc Krzyzanowski]

There is a story about solar energy and the Fuso Szulc expedition vehicle on:
http://michelszulckrzyzanowski.blogspot.com/2008/01/low-on-light.html

 

[Gold Boy]

There is a story about solar energy and the Fuso Szulc expedition vehicle on:
http://michelszulckrzyzanowski.blogspot.com/2008/01/low-on-light.html

hi Michel

ummmmm :scratches head:

thanks for the blog, it's a great resource for us all.

cheers
Simon

 

[Michel Szulc Krzyzanowski]

You are welcome, Simon.

 

[Martyn]

Not very many replies on this puzzling topic.

I'm not the expert on solar at AT, Mario "elcoyote" is the solar guy so I'd suggest sending him a PM and asking his opinion.

For what it's worth here is my opinion.

There seems to be a major problem with your solar system. It sounds like a wiring or control box issue as the readings from all of your panels are off.

I would suggest isolating each panel, as in disconnecting each panel from the system. I would do this as close to the panel as possible. Take a reading for each panel at this point. For a 110 watt panel on 12 volt with an 80% efficiency rating you should be getting 7 - 7.3 amps.

Test each panel isolated from the solar system.

If the reading are within the range the panels are OK. Reconnect each panel to the system separately and check the reading at the control box. The readings should be close to that taken at the panel, allowing for resistance.

If you have a major drop in volts or amps you have a short in that circuit. You would then have to either find the location of the short or run new wire.

 

[charlieaarons]

Remember also that the power rating is at about 17V, so max possible amps is P/17, not divided by 14 or 12. And Pmax needs to be multiplied by the cosine of the angle from vertical of the sun, or the sine of the angle from the horizon. So at 30 degrees from the equator on the equinoxes, it's 0.866XPmax/17 = max amps. At solar noon, with a clear sky.
Another useful formula: at sea level, max possible solar energy in solar panel useful visible spectrum = 1000W/meter squared. Panel efficiency to electricity =~ 0.23.
The person that increases that efficiency # by a significant amount using economic materials will become a multibillionaire.

Charlie

 

[jayshapiro]

Solar Progress

Michel,

Did you have any progress?

Also, how do you like the Trojan batteries? Are they the L16's?

Jay.

 

[egn]

Michael,

as you have discovered it was no good idea to combine solar panels of different make and size. Each of this panels has it MPP (maximum power point) at a different voltage, so it is nearly impossible to get the maximum out of them. But even you would have identical panels you will not get the maximum specified:

1. flat oriented panels with mono/multicrystaline cells will only get a reduced amount of solar energy depending on the angle of the sun.
2. every little shadow will reduce to output of a typical panel drastically
3. the charge controller has some loss
4. the battery may not be low enough to accept the maximum charge current
5. the panel are not running in the MPP
6. if the temperature is high the output is reduced (typical 20 % on hot days)

I have a few questions:

1. What was the state-of-charge of the batteries during the test?
2. What was the voltage of the batteries during the test?
3. What make of charge controller are you using?
4. I this a MPP, Shunt, ... controller?
5. What is the highest voltage for charging?
6. Does the charger temperature compensation?
7. How thick and long is the cabeling from the panels to charge controller?
8. How thick and long is the cabeling from the charge controller and the batteries?

First of all I would remove the two smaller panels from the charge controller. If you like to use this two panels you should use a separate charge controller for them in order that the other panels can run at the optimal point.

Check the cabeling and the connections. An ideal system would have equal runs of cable that is thick enough to have less than 0.3 V voltage drop at maximum current.

To test the panels it would be best to measure on a sunny and not to hot day at noon the unloaded voltage and the short curcuit current of each panel separately before the charge controller. But you have to have a ampere meter that can handle the current. Avoid any little shadow on the panels.

If the charge controller as an internal temperature compensation then keep the space around the controller very well ventilated. Otherwise the controller will throttle down the output voltage and current.

Emil

 

[Michel Szulc Krzyzanowski]

Many thanks for all your replies.
For the moment I am working in Mumbay, India on my project "The most beautiful people in the world" and the Fuso Szulc is in storage in Mexico.
Once back, somewhere in May, I will be able to follow up on all the comments.
For information on the proceedings in India, check: www.michelszulckrzyzanowski.blogspot.com