Usefulness Of MPPT Technology

MEXICOWANDERER wrote:
This isn't a trick question. I wish to take a "Short Course" in the reality versus hype of MPPT control... Users who have MPPT and can report real-life experience...

Let's say I get a pair of panels rated oh say, 180 watts each with a working voltage of how much (?) 36 volts... (360 watts of panels)

Arizona, high noon. 90F. perfect panel angle.

Battery bank at 12.25 volts static.

Monster size wire connecting panels to controller to batteries. Call it .2 ohm total resistance point to point.

What is a reasonable expectation for amperage delivered to the batteries?

Under the above operating condition, are some MPPT controllers more efficient than others? Are some more efficient than others with LESS direct angle of sunlight?

I am considering hauling panels back to Michoacan from where the hell is that place near Corona, CA.?

Has anyone reconfigured an array to double voltage with the available panels and controller, then verified total WATTAGE delivered to the battery bank did not degrade?

For long-term use does very high array to controller voltage, say in excess of 50 volts cause the silicon wafers to degrade faster?

This is where I learn from others on this forum. Thank you in advance.

I throw this out there for bare bones comparison.

Black Friday special pricing on this panel was $115 each. Ask for the black Friday special pricing before you get there, via email.

http://www.solarblvd.com/Solar-Panels-&-Systems-12-Volt-Solar-Panels/c1_269/p2667/Solar-Cynergy-120-Watt-12-Volt-Solar-

120 watt poly crystaline panel.Panel/product_info.html?osCsid=177e91ba68387bf12182791233b30bd5

$345 there, they are in Norco, ie North Corona. Pick them up in person, inspect them before leaving.

7 amps per panel x 3 = 21 amps in at what ever voltage you end up setting up a good cheap adjustable PWM at. You'll need 25 or 30 amps on the PWM.

ebay 30 amp controller.
You should have no problem getting 6.75 to 7 amps per panel, running them with 8 gauge wire you to the controller at what ever length you want. Mount the controller within 3 feet of your battery, and run some 4 gauge wire to the batteries, you'll be flowing 21 amps most of the day, or more. You can adjust that PWM controller to charge to 15.0 V to top off those wonderful Trojan batteries you love so much to get them to 100%, or drop it to 14.8 or leave it stock at the b2 setting of 14.4v. You can also set type of battery you want to charge also.

Don't scrimp on the connectors to the terminals to the battery, maybe full size post type connectors for the batteries. 21AH's time 7 hours, plus whatever extra you get on the front end and back ends of the day.

With PWM. If that's not enough, add another panel and another 7 amp hours, gets up up to 28 AHours per hour charge rate. The PWM will handle it. Size up to 6 gauge for the run to the controller, and to 2 gauge for the battery if you run 4 120 watt panels.